Note: Descriptions are shown in the official language in which they were submitted.
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PHARMACEUTICAL SEMI-SOLID COMPOSITION OF ISOTRETINOIN
TECHNICAL FIELD OF THE INVENTON
The present invention relates to an oral pharmaceutical composition of
isotretinoin containing at least two excipients, one of them being hydrophilic
(i.e.
having an HLB value superior or equal to 10), and the other being an oily
vehicle.
BACKGROUND OF THE INVENTION
Isotretinoin (13-cis retinoic acid or 13-cis vitamin A), its isomers and some
of its
analogs are widely known to have therapeutic activity in the treatment of
several
severe skin disorders including cystic acne, hypertrophic lupus erythematosus,
and
keratinization disorders. Some evidence exists supporting the activity of
isotretinoin in
basal cell carcinoma and squamous cell carcinoma.
Unfortunately, isotretinoin is also a highly toxic drug. Indeed, although
isotretinoin, which is a cis derivative, is known to be less toxic than all
trans vitamin A
derivatives, side effects resulting from its use such as headache, vomiting,
irritation of
mucosa and liver toxicity, occur frequently. Furthermore, isotretinoin is
known to be
highly teratogenic in both animals and humans.
In order to well understand the objectives and advantages of this invention,
it is
important to briefly summarize the physico-chemical pharmacokinetic properties
of
isotretinoin. lsotretinoin is a reddish-orange powder that is decomposed in
the
presence of light and atmospheric oxygen. lsotretinoin is poorly soluble in
water,
which results in its bioavailability being quite low after an oral intake (25%
in fasted
conditions and 40% in fed conditions). The maximum concentration (Cmax) is
reached
after 24 hours, while the (Cm,) of the active metabolite, 4-oxo-isotretinoin
is reached
after 6 hours. The elimination half-life of isotretinoin is of 7 to 37 hours
while the half-
life (t112) of the active metabolite is of 11 to 50 hours. The steady-state
concentrations
of isotretinoin are reached after 1 week of treatment.
Very few publications and/or patents about the pharmaceutical formulation of
isotretinoin are available. The drug is available on most markets under the
form of a
soft gelatin capsule containing a fatty liquid formulation of isotretinoin.
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U.S. Patent No. 4,464,394 describes for the first time the therapeutic use of
isotretinoin and also briefly describes compositions of isotretinoin. The
compositions
involve the use of an antioxidant agent and of a carrier like lactose,
starches or
polyethylene glycols.
EP 0184942 describes more specific compositions of isotretinoin involving the
use of an antioxidant, a chelating agent, a pharmaceutical carrier and a
suspending
agent. The composition obtained is described as being stable over time.
U.S. Pat. No. 4,545,977 relates to improved compositions of isotretinoin
wherein taurine is associated with isotretinoin to reduce the drug's side
effects.
U.S. Pat. No. 5,716,928 describes a method for increasing bioavailability and
for reducing inter and intra individual variability of an orally administered
hydrophobic
pharmaceutical compound. The method includes orally administering the
pharmaceutical compound with an essential oil or essential oil component in an
amount sufficient to provide greater bioavailability of the active ingredient.
U.S. Pat. No. 6,028,054 relates to a method for increasing bioavailability of
an
orally administered hydrophobic pharmaceutical compound to humans. The method
includes orally administering the pharmaceutical compound concurrently with a
bioenhancer comprising an inhibitor of an cytochrome P450 3A enzyme or an
inhibitor
of P-glycoprotein mediated membrane transport.
U.S. Pat. No. 5,993,858 describes a self-microemulsifying excipient
formulation
for increasing the bioavailability of a drug which includes an emulsion
including an oil
or other lipid material, a surfactant and an hydrophilic co-surfactant.
It is believed that the prior art does not disclose a composition of
isotretinoin
containing at least two lipid materials, one of them being hydrophilic. The
said
composition may be a suspension, emulsion or microemulsion.
BRIEF DESCRIPTION OF THE INVENTION
The advent of high throughput combinatorial chemistry and efficient receptor
based in vitro activity screening has resulted in molecules with poor
physicochemical
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properties (e.g., dissolution) for absorption across the gastrointestinal
tract, like
isotretinoin.
It is increasingly being recognized by the pharmaceutical industry that for
these
molecules drug delivery systems play an important role for improving oral
bioavailability.
Although the process of passive diffusion is responsible for absorption of non
ionized lipophilic molecules via the transcellular pathway, specialized
absorption
mechanisms, first-pass metabolisms and efflux systems at the gastrointestinal
wall
appear to play a major role in the lack of absorption and poor bioavailability
for some
molecules.
Isotretinoin is characterized by a low absolute bioavailability and a high
inter
and intra individual variability. lsotretinoin also presents a wide range of
side effects
among which some are severe (e.g., ocular, skin anemia, hepatic). It is
consequently
of particular interest to provide a reliable, stable and highly bioavailable
formulation of
isotretinoin.
lsotretinoin drug products marketed in the US before November 2012 all exhibit
a significant food effect as described in their product monographs and
measured by in-
vivo pharmacokinetic analysis. The present invention is related to a
pharmaceutical
composition comprising isotretinoin which does not exhibit significant food
effect as
determined in vivo by pharmacokinetic studies and in vitro by dissolution in
900 mL of
pH 7.5 Buffer containing 0.11% of pancreatin, 4.7% cholic acid, 0.14% sodium
dihydrogen phosphate, and 0.5% sodium hydroxide using a USP Apparatus #2
(paddles), at 100 rpm and 37 C. For the purpose of the present invention, the
term
"food effect" is defined as a significant difference in maximum concentration,
as
determined by Area Under the Curve, when an oral drug product is taken with or
without food.
Several possibilities are available to the formulator to increase the
bioavailability
of active ingredients (Table A).
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Table A
Option Formulation technique
Use of salts, polymorphs. Precursors of the active molecule (=prodrugs)
II Reduction of the particles' size of the active principle and of the
excipients used (by
trituration, grinding, micronization, precipitation controlled by solvent,
temperature or
ultrasonics).
Ill Solid dispersions:
Eutectic mixes
Solid solutions
Vitreous solutions
IV Recrystallization in an aqueous solution of a surfactant
V Modification of the microenvironment:
Hydrophilization
pH (acidification)
VI Incorporation of the active principle to lipidic systems
It has been found that a semi-solid dosage form containing isotretinoin was
advantageous for obtaining a good bioavailability of the isotretinoin. A semi-
solid
dosage form containing isotretinoin is a form in which isotretinoin is mixed
with suitable
melted excipients. The molten mix is then filled, for example, into hard
gelatin capsules
or other pharmaceutically acceptable capsules. At ambient temperature
(temperature
for example of less than 20 C), the content of the capsule is a solid while at
a
temperature higher than 20 C (for example at a temperature greater than or
equal to
30 C, advantageously greater or equal to 35 C, preferably substantially at
body
temperature +/-37 C), it is a liquid or semi-solid (paste). The isotretinoin
may be
solubilized in the mix of excipients or partially solubilized. The active
ingredient may
also be formulated as a suspension, emulsion or microemulsion.
Various lipidic excipients are available to the formulator to obtain a semi-
solid
formulation. Excipients compatible with hard gelatin capsule shells are:
lipophilic
liquid vehicles (refined specialty oils, medium-chain triglycerides and
related esters),
semi-solid lipophilic vehicles, solubilizing agents, emulsifying agents and
absorption
enhancers. The classification of fatty excipients is based on the
hydrophilicity or
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lipophilicity of the excipients, characterized by the hydrophilic/lipophilic
balance value
(HLB). Examples of lipophilic excipients are vegetable oils (e.g., peanut oil,
olive oil,
soyabean oil, etc.) fatty acids (e.g., stearic acid, palmitic acid, etc.)
fatty alcohols,etc.
Examples of hydrophilic excipients are polyethylene glycol (PEG) with a
molecular
weight of greater than 3,000. Examples of amphiphilic (i.e., having lipophilic
and
hydrophilic properties) excipients are Poloxamers, Lecithin, PEG esters
(Geluciree),
etc.
There are numerous advantages of the semi-solid formulations of isotretinoin
of
the present invention including: protection of the active ingredient from air
and
humidity, potential to increase the dissolution rate of the drug and hence its
bioavailability, reducing the risk of the operator making the formulation
being exposed
to isotretinoin, reducing the risk of cross contamination, no possibility of
demixing
under the effect of vibrational mixing during the manufacturing process, and
the facility
of the production process.
The choice of the nature of the formulation influences the stability of the
pharmaceutical formulation and the bioavailability of the isotretinoin
contained in it.
Generally, a maximum bioavailability is achieved by preparing and keeping the
drug in
the amorphous/solubilized state in a solid dispersion or in a lipid-based
formulation.
For these systems, the obstacle to dissolution that we are avoiding is
significant
"washing out" of the compound from solution into an insoluble crystalline form
during
the dissolution/release step in vivo.
These systems may consist of suspension, emulsion, microemulsion, self-
emulsifying drug delivery systems (SEDDSO) or self-emulsifying microemulsion
drug
delivery system (SMEDDS ).
Microemulsions have the added advantage over suspensions, such as
emulsions and dispersions, since thermodynamically they are more stable, they
can
be manufactured with little energy input and have generally a longer shelf-
life.
Nevertheless, a microemulsion formulation is not a guarantee of higher
bioavailability
in comparison to a suspension, as described hereafter.
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The formation of oil-in-water (0/W) and water-in-oil (W/0) micro emulsions
usually involves a combination of 3-5 basic compounds i.e. oil, surfactant, co-
surfactant, water and electrolytes. The challenge is to select, for a
particular
application, oil(s) and surfactant(s) that are acceptable from a toxicological
perspective
and that provide a high bioavailability of the drug, i.e. isotretinoin.
The assessment of the quality of semi-solid lipid based formulations is quite
difficult since the in vitro dissolution test is of little help. Indeed, the
in vitro/in vivo
correlation between dissolution and bioavailability is very poor for this kind
of
formulation. Other analytical tools are available to the formulator to try to
predict the in
vivo bioavailability of isotretinoin from various formulations, including the
CACO-2 cells
model, assessment of the percentage of drug dissolved in the formulation,
differential
scanning calorimetry, microscopy, etc.
Nevertheless, none of these analytical tools present a guarantee of in
vitro/in
vivo correlation and ultimately only pharmacokinetic studies on human subjects
are
reliable to assess the bioavailability of the drug.
DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS
The pharmaceutical composition of the invention is an oral semi-solid
pharmaceutical composition of isotretinoin containing two lipidic excipients,
one of
them being hydrophilic and the other being an oily vehicle. The hydrophilic
excipient
has a HLB value of at least 10, for example equal to 10, but preferably
greater than
10, such as greater or equal to 12, for example between 12 and 14.
The pharmaceutical composition of the invention contains advantageously at
least one hydrophilic excipient with a HLB value of at least 10 selected from
the group
consisting of glyceroyl macrogolglycerides, polyethyleneglycol derivatives,
and
mixtures thereof. Preferably, the pharmaceutical composition contains from 20
to 80%
by weight of a hydrophilic excipient with a HLB value of at least 10 selected
from the
group consisting of glyceroyl macrogolglycerides, polyethyleneglycol
derivatives, and
mixtures thereof.
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The oily vehicle is selected from the group consisting of vegetable oils,
medium
chain triglycerides, fatty acid esters, amphiphilic oil, glycerol oleate
derivative, and
mixtures thereof. For example, the composition may contain from 5 to 70% by
weight
of an oily vehicle selected from the group consisting of vegetable oils,
medium chain
triglycerides, fatty acid esters, amphiphilic oil, glycerol oleate derivative,
and mixtures
thereof.
According to another detail of preferred pharmaceutical compositions of the
invention, the composition further contains at least one surfactant,
preferably selected
from the group consisting of sorbitan fatty acid esters, polysorbate
derivatives,
polyoxyethylene sorbitan fatty acid esters, sodium laurylsulphate, derivatives
of
lecithine, propylene glycol esters, fatty acid esters of propylene glycol,
fatty acid esters
of glycerol, polyethylene glycol, and mixtures thereof. For example, the
composition
contains from 1 to 10% by weight of at least one surfactant.
Furthermore, the pharmaceutical formulation of the invention contains
advantageously at least one disintegrant, preferably selected from the group
consisting of povidone derivative, sodium croscarmellose and mixtures thereof.
The pharmaceutical composition of the invention may contain one or more
surfactants and/or one or more disintegrants, but contains preferably one or
more
compounds acting as surfactants and one or more compounds acting as
disintegrants.
The invention relates also to a pharmaceutical acceptable capsule containing
at
least one semi-solid composition of the invention, for example at least one
composition
of the invention as disclosed above. The capsule is for example selected from
the
group consisting of hard gelatin capsules, soft gelatin capsules, hypromellose
capsules, and starch capsules.
The invention also relates to an oral pharmaceutical composition comprising
isotretinoin, wherein said oral pharmaceutical composition is substantially
devoid of
food effect as characterized by a dissolution profile wherein at least 70% of
the oral
pharmaceutical composition is dissolved after about four hours in a USP2
dissolution
apparatus at a paddle speed of 100 rpm, and a dissolution media composed of
900
mL of pH 7.5 buffer containing 0.11% pancreatin, 4.7% cholic acid, 0.14%
sodium
dihydroxide phosphate and 0.5% sodium hydroxide at 37 C.
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The dissolution test method of the present invention is carried out in 900 mL
of
pH 7.5 Buffer containing 0.11% of pancreatin, 4.7% cholic acid, 0.14% sodium
dihydrogen phosphate, and 0.5% sodium hydroxide using USP Apparatus #2
(paddles), at 100 rpm and 37 C. Dissolution samples are taken after 4 hours,
and
diluted to 50% with acetonitrile. Any USP-acceptable dissolution equipment may
be
used. Preferably, a USP dissolution apparatus #2 or #3 is used. More
preferably, a
USP #2 (paddle) dissolution apparatus equipped with 900 mL round bottomed
and/or
peak vessel flasks is used.
To ensure the pharmaceutical composition remains surrounded by the
dissolution media, sinkers can be used with any dosage form that floats in the
dissolution media. A small, non-reactive wire helix may be attached to the
dosage
form to keep it at the bottom of the vessel. Preferred sinkers include the
Sotax
sinker, basket sinker, pronger sinker, 0-ring, or spiral sinker. More
preferred sinkers
include the Japanese Pharmacopeia basket sinkers.
The pH of the media may vary from 2.0 to 12.0, preferably from 4.0 to 8.0, and
more preferably from 7.0 to 8Ø The buffer of the media may be comprised of
phthalate, phosphate, barate, and/or acetate, and will depend on the final pH
value.
Sodium dihydrogen phosphate is the preferred buffer. Pancreatin is added to
the
media to destroy any gelatin cross-linking.
Cholic acid is added to increase the solubilization of isotretinoin. The
amount
may vary from 0.1% to 0.6%, preferably from 0.3% to 0.4%.
For determining the amount of the isotretinoin in the samples after 4 hours of
dissolution, any validated analytical method may be used, including UV
spectrophotometry, colorimetry, HPLC, or capillary electrophorese. The
preferred
analytical method is HPLC equipped with a UV detector of 353 mm and C18
column,
for example, LiCrospher 100 RP-18 end capped, with a flow rate of 2.0 mUmin
of
mobile phase consisting of acetonitrile:water:glacial acetic acid (85:15:0.5)
at a
temperature of 40 C.
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BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a ternary diagram of a formulation containing only Gelucire 50/13
and
soybean oil, the third component being water;
FIG. 2 shows the dissolution rate of a reference product (Roaccutane-20 mg
active agent), of a suspension containing 20 mg lsotretinoin and of an
emulsion
SEDDS containing 10 mg lsotretinoin;
FIG. 3 shows an In vivo comparative pharmacokinetic profile of isotretinoin;
FIG. 4 gives the comparative pharmacokinetic profile of different formulations
for isotretinoin,
FIG. 5 gives the comparative pharmacokinetic profile of different formulations
for 4-oxo-isotretinoin, the active metabolite of isotretinoin and
FIGS. 6 and 7 describe the mean pharmacokinetic profile of isotretinoin and 4-
oxoisotretinoin for two formulations.
FIG 8 shows in vivo comparative pharmacokinetic profiles of Isotretinoin
obtained after administration of 2 x 20 mg of the present invention versus 20
mg of
the product in the market (Accutanee) taken with and without food.
DESCRIPTION OF EXAMPLES
The present invention relates to a semi-solid formulation of isotretinoin
containing at least 2 lipidic excipients, one of them being a hydrophilic
excipient
(having a high HLB value, namely >10) and the other an oily excipient. The
molten mix
of these two excipients allows total or partial (depending on the ratio
between
excipients) dissolution of the isotretinoin. Different kinds of formulations
(SEDDS or
suspensions) of isotretinoin have been formulated. For suspensions, it was
possible to
dissolve a high fraction of isotretinoin in the mix of excipients and even the
whole
quantity of the active ingredient if the manufacturing conditions (high
temperature and
long time of mixing) and the formulations were optimized. Excipients
particularly
suitable for the dissolution of isotretinoin were lauroyl Macrogo1-32
glycerides
(Gelucire 44/14, Gattefosso) and Stearoyl Macrogo1-32 glycerides (Gelucire
50/13,
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Gattefosse). When those hydrophilic components are melted together with an
oily
vehicle, it allows obtaining very stable suspensions of isotretinoin in which
an
important part of the active ingredient is dissolved. A surfactant may also be
added to
the formulation to further improve the physical stability of the suspension.
SEDDS formulations of isotretinoin are also stable and may give an improved
bioavailability of the drug.
Ternary diagrams illustrate the different areas corresponding to different
physical states, namely, coarse emulsion, true emulsion, lamellar solution or
micellar
solution, as the ratio between excipients is varied. The behavior of the
formulation in
the presence of water changes when the ratio changes. One example of this
ternary
diagram is given in FIG. 1 for a formulation of isotretinoin containing
Gelucire 50/13
and soybean oil.
Example 1
Effect of different Lipophilic Compounds
The effect of different lipophilic excipients was evaluated in the dosage form
of
semi-solid capsules. The semi-solid capsules were made by addition of the
active
substance to the pre-melted lipophilic compounds followed by the filling of
the liquid
into hard gelatin capsule.
The active substance was incorporated into formulations, listed in table 1,
consisting of glyceroyl macrogolglyceride associated with soybean oil or
derivative,
medium chain triglyceride.
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TABLE I
Formulations number 1 2 3 4 5
lsotretinoin 20 20 20 20 20
Labrafil M1944 CS 132
Gelucire 50/02 198 93
Gelucire 44/14 217
Gelucire 50/13 76 60 60
Soybean oil 304 320
Mygliol 320
The use of stearoyl macroglyceride (Gelucire 50/13, Gattefosse) and soybean
oil allows provides a formulation with a dissolution profile similar to the
reference
(Roaccutane 20 mg, Roche).
The formulations with Labrafil or Gelucire 50/02 are too lipophilic to give
a
good dissolution in water.
In general, the use of an oily excipient can improve the absorption of a
lipophilic
drug by increasing the solubility of the drug in the lipidic phase, but the
release of the
active ingredient from the formulation can be slowed down due to the high
affinity of
the lipophilic drug for the oily phase.
The use of dispersed systems (emulsions or suspensions) instead of only
lipophilic or hydrophilic vehicles, improves the absorption of the drug as
well as
increasing a larger contact surface.
Concerning the Gelucire , the process of drug release varies according to the
HLB of the excipient. Gelucire with high HLB values were found to be the most
favorable for a rapid release of the drug (by diffusion and erosion).
The drug release profiles of Formulations 1 to 5 were evaluated in phosphate
buffer pH 7.5 with laurylsulfate and pancreatin. The percent of isotretinoin
released
after 4 hours is given in the following table II.
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TABLE II
Percent of isotretinoin released after 4 hours
Formulations Number 1 2 3 4 5
% released 20.1 69.1 46.0 60.3 78.1
The percent of isotretinoin released from the reference (Roaccutane8 20 mg)
after 4 hours is 55.37%.
Example 2
Influence of the Ratio Oily Vehicle/Surfactive Agent on the Dissolution
and Absorption of the Formulation
The study of the ratio of oily vehicle/surfactive agent with the construction
of a
ternary diagram gives information on the dissolution profile of the
formulation in water.
Stearoyl macrogolglyceride (Geluciree 50/13), which is known to be a drug
solubilizer and emulsifying agent of different drugs (in SMEDDSO or SEDDSO),
was
tested in association with soybean oil.
This component has the ability to solubilize a great part of isotretinoin in
the
formulation. This data is listed in table Ill.
TABLE Ill
Formulations number 1 2 3 4 5 6
lsotretinoin 20 10 10 20 20 20
Soybean oil 270 135 40 152 57 133
Gelucire 8 50/13 84 42 200 228 323 247
Filling weight 374 187 260 400 400 400
Ratio oil/ Gelucire 8 50/13 3.2 3.2 0.2 0.67 0.17 0.54
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In the presence of water, the behavior of these formulations are different
Formulations 1 and 2: formation of coarse emulsion with large droplet sizes
Formulations 3 and 5: formation of micellar phase or microemulsion
Formulations 4 and 6: formation of emulsion with homogeneous droplet size
The percentage of isotretinoin released increases generally with the
percentage
of Gelucire in the formulation (increased solubility of the active in this
vehicle). For
Formulation 1 (ratio oil/Gelucire 50/13=3.2) 54.9% released after 4 hours and
for
Formulation 3 (ratio oil/Gelucire 50/13: 0.2), 91.2% released after 4 hours.
Dissolution Test
For poorly soluble molecules, the prediction power of the in vitro dissolution
test
is weak since the in vitro/in vivo correlation is known to be poor.
Nevertheless, an
optimized dissolution test (using enzymes and surfactant) is of some help to
assess
the rate of release of the drug from the lipidic composition. It must be noted
that the
conditions of the dissolution test (dissolution medium, speed of the paddles,
temperature, etc.) influence the results of the test and should consequently
be
standardized to allow comparison between various formulations.
The conditions of the solution test used for assessing the dissolution of
isotretinoin were the following
paddle apparatus
150 rpm
3700
buffer pH 7.5 with laurylsulfate 2.5% and pancreatin 1 g/L
FIG. 2 shows the dissolution rate of a reference product (Roaccutane8-20 mg
active agent), of a suspension containing 20 mg lsotretinoin and of an
emulsion
SEDDS containing 10 mg Isotretinoin (formulation given below).
As the information provided by the dissolution test is poor in terms of
correlation
with in vivo bioavailability, it is of interest to dispose of other means to
predict the in
vivo bioavailability.
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The caco-2 cell culture system can be used for determining permeability of
compounds (especially for poorly soluble compounds). The caco-2 cell model
allows
one to measure the transport of drug from the apical to the serosal side as
well as
from the serosal to the apical side. This gives the ability to determine if an
efflux
system is operational.
The caco-2 cells model is interesting because:
(a) The cells used are from human origin (contrary to the models using
segments of animal guts). The cells are from an adenocarcinoma of the
human colon but spontaneously differentiate into small intestine's epithelial
cells. When put in culture, the cells form a monolayer of polarized cells
expressing several enzymatic systems.
(b) The model offers a better prediction of the human intestine absorption
than
do animal models.
(c) The reproducibility of the test is relatively high.
(d) The model allows one to take samples from both apical and basolateral
sides.
As described below, Caco-2 cells experiments have been performed with one
SEDDSO and one suspension isotretinoin formulation.
Results
It was first proven that neither the active ingredient nor the excipient used
in the
formulations were toxic to the cells. It was also proven that the integrity of
the
membranes of the cells was maintained during the entire experiment.
Methodology:
The formulations tested were put in solution in 250 ml of BME. Taurocholate
(10
mM) was added to the solutions to better replicate the in vivo physiological
conditions.
The different solutions so prepared were put in contact with Caco-2 cells at
the apical
or basolateral side. The cells culture inserts were incubated for 3 hours at
37 C and
samples of 100p1 taken every hour for analysis.
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The formulations tested were the following:
TABLE IV
SEDDS
Formulation Suspension
26F97/1 25F97/1
lsotretinoin 10 mg 20 mg
Gelucire 50/13 134 mg 83.7 mg
Phospholipon 90 11 mg
Tween 80 71 mg
IPP 24 mg
Soybean oil 270 mg
Gelatin Capsule 1 1
Results
Passage of Formulations from Apical Side Basolateral Side
TABLE V
Time SEDDS Suspension SEDDS + Suspension+ Control
minutes (26F97/1) (25F97/1) TC TC
60 0.7721 0.6708 0.7019 0.6469 0.0718
120 2.4096 0.8749 1.4347 0.9513 0.1836
180 2.6226 1.1311 3.2419 1.5073 0.6156
Passage of Formulations from Basolateral Side Apical Side
TABLE VI
Time SEDDS Suspension SEDDS + Suspension+ Control
minutes (26F97/1) (25F97/1) TC TC
60 2.0496 0.3948 8.1291 0.8713 0.0650
120 3.0844 0.9068 8.3496 1.8460 0.1131
180 4.3653 1.0763 9.7110 2.0779 0.1481
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The results demonstrate that the passage of isotretinoin is superior for the
SEDDS formulation than for the suspension formulation. In order to confirm
these
results, a comparative pharmacokinetics study has been performed.
PK Studies
The bioavailability of SEDDS (26F97/1) and suspension (25F97/1) isotretinoin
formulations has been assessed and compared to the bioavailability of the
reference
(Roaccutane 20 mg, Hoffman La Roche) on six healthy volunteers in a single
dose,
three way, cross-over pharmacokinetic study). The drug was taken with food
(Europeanbreakfast). The plasma concentration of isotretinoin and its active
metabolite 4-oxo-isotretinoin were quantified using a fully validated LC/MS/MS
method.
FIG. 3 describes the mean pharmacokinetic profile obtained for each
formulation.
The following TABLE VII gives the value of the main pharmacokinetics
parameters
obtained for each formulation of isotretinoin.
Formulations AUC 72h C max T max
(ng = h/ml) (ng/ml) (h)
Roaccutane 20 mg 1747.89 116.63 1.83
(96C15315AA)
Suspension 20mg 4308.72 230.96 5.67
(25F97/1)
SEDDS01 Omg 1494.64 98.36 3.00
(26F97/1)
It appears that both the SEDDS and the suspension formulations are able to
significantly increase the bioavailability of isotretinoin in comparison to
the marketed
reference product. Indeed the ratio between AUC72h of the suspension 20 mg and
Roaccutane 20 mg is of 2.47. The SEDDS 10 mg present an AUC72/1 similar to
that
of Roaccutane 20 mg what means an approximately 2-fold increase of
bioavailability
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(ratio AUC72h SEDDS 10 mg/ AUC70, Roaccutane 20 mg =0.86). Furthermore, the
suspension and SEDDS formulations both presented a lower intra-individual
variability of the bioavailability as demonstrated by the values of relative
standard
deviations (rsd) which are of 36.0%, 22.72% and 28.18% for Roaccutane 20 mg,
suspension 20 mg and SEDDS 10 mg, respectively.
Nevertheless, the results obtained in vivo are not correlated with the results
obtained on caco-2 cells since with this model the permeability of the SEDDS
formulation was much higher than the permeability of the suspension
formulation. In
contrast, in the in vivo testing the suspension formulation gave the best
results.
A second pharmacokinetic study was performed on completely different
formulations (6 subjects, 2-way, fed, cross-over study). Specifically, in the
second
pharmacokinetic study the formulations of isotretinoin under the form of a
suspension
in which the ratio Gelucire 50/13 and soybean oil was very different from the
suspension formulation used in the first pharmacokinetic study.
The two formulations tested are listed in Table VIII.
TABLE VIII
Batch number H23K99/1 H07L99/1
lsotretinoin 20 20
Gelucire050/13 247 240
Soyabean oil 133 130
1 Span 800 20
FIG. 4 provides the comparative pharmacokinetic profiles of the isotretinoin
formulations of Table VIII.
FIG. 5 provides the comparative pharmacokinetic profiles of the isotretinoin
formulations of Table VIII for 4-oxo-isotretinoin, the active metabolite of
isotretinoin.
In order to confirm the first bioavailability data obtained with the present
invention, a larger pharmacokinetic study has been performed. The
bioavailability of a
capsule of isotretinoin 16 mg (see Table IX below for the formulation)
according to the
CA 02836228 2013-12-13
18
present invention has been assessed and compared to the bioavailability of the
reference (ROACCUTANE 20 mg capsule, Roche) on 24 healthy subjects.
This study (SMB-ISO-SD011) was a single dose, two treatment, two period, two
sequence, randomized, crossover design with at least 18 days wash-out between
the
two periods.
The subjects were healthy Caucasian volunteers of both sexes (non-pregnant,
non-breast-feeding), aged 18 to 50 years, non-smokers or smoking less than 10
cigarettes per day.
The drug was taken with food (a European breakfast).
Blood samples were collected according to the following sampling schedule: pre
dose and 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 10 h, 12h, 14 h, 24 h, 36 h,
48 h, 72 h,
96 h, 120 h, 168 h and 216 hours post-dose.
The plasma concentration of isotretinoin and its active metabolite, 4-oxo-
isotretinoin, were quantified using a fully validated LC/MS/MS method. The
continuous
variables were evaluated according to a univariate ANOVA, based on log-
transformed
data. The Wilcoxon non-parametric ANOVA were used where appropriate.
Bioequivalence was evaluated using the Shuirman two one-sided t-test (90% Cl)
and
the Westlake single sided confidence interval (95% CL).
FIGS. 6 and 7 describe the mean pharmacokinetic profile of isotretinoin and 4-
oxo-isotretinoin for the two formulations (n=24 subjects) while the Tables X
and XI
provide the comparative, main pharmacokinetic parameters.
TABLE IX
Formulation of isotretinoin 16 mg (mg/capsule)
Isotretinoin 16
Stearoyl macrogol glycerides (Gelucire 50/130) 192
soybean oil refined 104
sorbitane oleate (Span 80"') 16
As seen below, the dose of 16 mg of the formulation corresponding to the
present invention gives a bioavailability similar to 20 mg of the marketed
formulation,
CA 02836228 2013-12-13
19
which provides evidence of the supra-bioavailability of the formulation
corresponding
to the present invention.
Table X and XI provide the value of the main pharmacokinetics results and
statistical analysis obtained for each formulation (i.e., ROCCUTANE 20 mg and
isotretinoin 16 mg) of isotretinoin and 4-oxoisotretinoin.
This study demonstrated that ROACCUTANE 20 mg and isotretinoin 16 mg
are bioequivalent after a single oral dose administration of each product in
fed
conditions. Indeed, the primary parameters AUG (AUC.3 and AUC216h) were within
the
predetermined confidence interval.
This study demonstrated also that lsotretinoin 16 mg according to the
invention
has a safety profile comparable to that described in the literature for other
isotretinoin
preparations and similar to that of ROACCUTANE020 mg.
Pharmacokinetic Results and Statistical Analysis of Comparative Study in 24
Volunteers for lsotretinoin (Log-Transformed Data). (See Table X)
TABLE X. Bioequivalence tests / lsotretinoin
Results
Parameter ROACCUTANE Isotretinoin Shuirman 90% Westlake 95%
20mg 16mg Cl Range CL
AUC.0 5657.09 (ng html) 5696.92 (ng h/ml) 92-123 him!) 19.07
SD 2682.98 1938.89
RSD 47.42 34.03
AUC2i6h 5601.36 (ng h/ml) 5664.39 (ng h/ml) 92-124 19.51
SD 2670.85 1953.52
RSD 47.68 34.48
C 386.68 (ng/ml) 441.79 (ng/ml) 103-140 28.81
SD 218.21 197.43
RSD 56.43 44.68
Tmax 4.92(h) 4.50(h)
SD 2.22 0.66
RSD 45.24 14.65
CA 02836228 2013-12-13
Pharmacokinetic results and statistical analysis of comparative study in 24
volunteers
for 4-oxoisotretinoin (log-transformed data) (See Table XI)
Table Xl. Bioequivalence tests / oxoisotretinoin
Results
Parameter ROACCUTANE lsotretinoin Shuirman 90% Westlake 95%
20mg 16mg Cl Range CL
AUCco 5750.36 (ng himl) 5769.04 (ng 92-124(h/m1) 19.65
him')
SD 2717.38 2161.97
RSD 47.26 37.48
AUC216h 5638.32 (ng himl) 5712.21(ng 92-125 20.46
h/ml)
SD 2704.73 2126.61
RSD 47.80 37.23
Cmax 111.52 (ng/ml) 115.15 (ng/ml) 94-125 20.18
SD 69.62 66.25
_
RSD ' 62.43 57.53
Tmax 17.83(h) 16.33(h)
SD 10.60 10.11
RSD 59.43 61.88
Example 3
To study the effect and verify the capability of the dissolution test,
containing
cholic acid, to detect Isotretinoin containing formulations without food
effect the
following formulation was prepared, tested in dissolution and in vitro studies
and
compared to the commercially available product in the market (Accutanee).
Gelatin
capsules containing 20 mg of Isotretinoin were prepared as follows.
CA 02836228 2013-12-13
21
Table XII
Ingredient Amount [kg]
Isotretinoin USP 2.224
Stearyl Macrogol Glycerides 26.7
Soybean Oil, USP 14.5
Sorbitan Monooleate, NF 2.22
Propyl Gallate, NF 0.00912
The pre-weighed amounts of stearyl macrogol glycerides, soybean oil, sorbitan
monooleate, and propyl gallate were added in a double-jacketed stainless steel
container equipped with a mixing device, and heated at a temperature between
about
65 C and about 85 C. When all excipients were molten, isotretinoin was added
to the
container while mixing. 410 mg of the molten blend was added into size #0
gelatin
capsules, producing capsules containing 20 mg of isotretinoin.
Dissolution testing: A dissolution test using 6 capsules of the present
example
was performed. The dissolution test is performed in accordance with general
rules of
USP for dissolution testing
A dissolution medium pH 7.5 [20 L] was prepared by introducing 27.6 g of
sodium dihydrogen phosphate in an appropriate container and dissolving it with
about
4 liters of water. Next, 12 liters of water were added. Thereafter, 380 mL of
sodium
hydroxide 6N were progressively added under stirring. If needed, the mixture
was
sonicated until all of the sodium dihydrogen phosphate is dissolved. 940 g of
cholic
acid was progressively added under stirring until totally dispersed. If
necessary, small
amounts of NaOH 6N were added until dissolved. Water was added to bring the
total
volume to about 20 L, mixed, and the pH was adjusted to 7.5 with NaOH if
necessary.
The exact amount of medium to be used was then removed, and 1 g of pancreatin
per
each 900 mL of medium was added and mixed.
The dissolution test parameters were: dissolution volume 900 mL; temperature
37 C; paddle rotation speed 100 rpm; test time for sampling 4 hours;
quantification
HPLC/UV at 353 nm 4 nm.
CA 02836228 2013-12-13
22
Test: 900 mL of dissolution medium was slowly added to each dissolution
vessel and heated at 37.0 C 0.5 C. Paddles were lowered into the dissolution
medium and the paddle rotation speed was set to 100 rpm. Each of the six
capsules
was inserted into a corresponding sinker, and one sinker containing one
isotretinoin
capsule was introduced into each dissolution vessel. Samples were taken (10.0
mL)
in each dissolution vessel after 4 hours.
The solution was immediately filtered slowly through a 0.45 pm filter, and the
first milliliters were discarded and introduced into a glass vial. The samples
were
further diluted by pipetting 5 mL of the sample and 5 mL of acetonitrile into
a container.
Two milliliters of the diluted sample were mixed and transferred to a HPLC
amber vial.
Analysis: The chromatographic conditions were: column LiCrospher 100 RP-
18 end capped (125 x 4 mm), 5 pm or equivalent; mobile phase
acetonitrile:water:acetic acid glacial (85:15:0.5); flow rate 2.0 mL/min;
temperature
40 C; detection UV at A 353 nm 4 nm; injection 80 pL; stop time 4 minutes.
To prepare the mobile phase (85:15:0.5 acetonitrile:water:acetic acid), 850 mL
of acetonitrile, 150 mL of water, and 5.0 mL of acetic acid glacial were added
to a one
liter flask. The mix was then homogenized and degassed in an ultrasonic bath
for 15
minutes before use.
Methylene Chloride Reagent: One liter of methylene chloride was added to 50
g of sodium bicarbonate. The solution is shaken and allowed to stand
overnight. At
the time of use, it is filtered and 10 mg of butylated hydroxytoluene are
added for each
mL of reagent.
The isotretinoin-containing formulation has a reduced food effect if the
results
obtained comply with the following specifications:
CA 02836228 2013-12-13
23
Table XIII
Stage S1 Stage S2 Stage S3
Number of capsules n=6 Number of capsules n=12 Number of capsules n=24
Mean of 12 units NLT 75% Mean of 24 units NLT 75%
Each of the 6 units is NLT
NMT 2 units are LT 60%
80% All units are NLT 60%
No unit is less than 50%
Demonstration that the formulation should not have a significant food effect
since the result obtained for 6 units was 92% dissolved. [limit for n = 6 NLT
80%]
An open label, single dose, four-way, randomized crossover comparative
bioavailability of two formulations of isotretinoin capsules in healthy
volunteers under
fed and fasting conditions was conducted with the same formulation: PRMI Study
2003-627.
The objective of the study was to evaluate the comparative bioavailability
between lsotretinoin 2 x 20 mg capsules (Example 1) and Accutane 40 mg
capsules
in healthy male and female volunteers under fasting and fed conditions.
Treatment A (Test): Isotretinoin 20 mg Capsules [40 mg administered after an
overnight fast of at least 10 hours]
Treatment B (Test): Isotretinoin 20 mg Capsules [40 mg administered after a
modified high fat, high calorie breakfast]
Treatment C (Test): Accutane 40 mg Capsules, Lot No.: U0622; [40 mg
administered after an overnight fast of at least 10 hours]
Treatment D (Test): Accutane 40 mg Capsules, Lot No.: U0622; Expiration
Date: 10-2004 [40 mg administered after a modified high fat, high calorie
breakfast]
Sixty (60) (40 male and 20 female) subjects were dosed in Period 1, with 57
subjects completing the entire study.
CA 02 83 622 8 2 0 13-12-13
24
Blood samples were obtained at -10, -2, 0, 1, 2,2.5, 3, 3.5, 4,4.5, 5, 5.5, 6,
7,
8, 10, 12, 14, 16, 20, 24, 36, 48, and 72 hours following drug administration.
No serious adverse events were reported during the study.
The mean lsotretinoin plasma concentration versus time are shown in Fig. 8
Table XIV
Plasma Isotretinoin Results
(n=57)
Treatment Arithmetic Contrast 90% CI
Parameter Type Trt (CV%) Geometric Type Code Ratio
(%) (%) CV%
T - Fast A 4676.08 (28) 4470.45 T: Food Effect B
vs. A 149.78 140.52 -
T - Fed B 6858.70 (21) 6695.87 R: Food D vs. C
252.60 159.66
R - Fast C 2619.26 (30) 2500.01 Effect A vs. C 178.82
236.98 -
AUCi R - Fed D 6561.62 (26) 6315.15 T/R - Fast
B vs. D 106.03 269.26
21
(mg.h/mL) T/R - Fed 167.76 -
190.60
99.47 -
113.02
T - Fast A 347.00 (35) 323.18 T: Food Effect B
vs. A 134.39 122.60 -
T - Fed B 466.43 (38) 434.33 R: Food D vs. C
267.53 147.32
R - Fast C 169.66 (29) 161.43 Effect A vs. C
200.20 244.05 -
Cmax R - Fed D 471.32 (41) 431.88 T/R - Fast
B vs. D 100.57 293.28
(mg/mL) T/R - Fed 182.63 -
219.46
91.74 -
110.24
T = Test
R = Reference
CA 0 2 8 3 62 2 8 2 0 13-12-13
Table XV
Plasma 4-oxo-isotretinoin results
(n=57)
Treatment Arithmetic Contrast 90% CI
Parameter Type Trt (CV%) Geometric Type Code Ratio (%) (%) CV%
T - Fast A 12962.12 (43) 11865.08 T: Food Effect B vs. A
178.01 162.09
T - Fed B 22080.03 (31) 21121.13 R: Food D vs. C
312.59 195.50
R - Fast C 6667.38 (46) 6049.60 Effect A vs. C 196.13
284.63 -
AUCi R - Fed D 20485.24 (39) 18910.45 T/R - Fast 8
vs. D 111.69 343.30
31
(mg.h/mL) T/R - Fed 178.59 -
215.39
101.70 -
122.66
T - Fast A 177.23 (39) 163.73 T: Food Effect B vs. A
215.24 196.12 -
T - Fed B 368.76 (28) 352.42 R: Food D vs. C
439.82 236.23
R - Fast C 75.61 (35) 70.55 Effect A vs. C 232.09
400.75 -
Cmax R - Fed D 336.61 (38) 310.28 T/R - Fast B vs. D
113.58 482.71
31
(mg/mL) T/R - Fed 211.48 -
254.71
103.49 -
124.65
T Test
R = Reference
CA 02836228 2013-12-13
26
The results of the pharmacokinetic study show that for Isotretinoin plasma
levels as expressed by Area Under the Curve (AUC) and maximum concentration
(Cam) (Table XVI) the formulation of Example 3 does not have a significant
food effect.
Table XVI Summary of Pharmacokinetic parameters
Isotretinoin plasma levels
AUCi Cmax
Present Present
Product in Product in
invention Ratio invention Ratio
the market the market
Example 3 Example 3
Fed 6858 6561 105 466 471 99
Fasted 4676 2619 179 347 169 205
Dissolution test
The need for a biorelevant dissolution method for isotretinoin compositions
that may
replace the costly biostudy by a dissolution test is of the utmost need for
the
pharmaceutical industry. Such a biorelevant dissolution method will permit one
not
only to assure the quality and performance of each and every lot produced but
also will
drastically reduce the cost and time needed each time a change is required
during the
lifespan of the product. Such a dissolution test also would be very valuable
in the
research and development phases of a project since it will permit formulators
to
distinguish between isotretinoin-containing formulations with and without food
effect.
The United States Pharmacopeia (USP) is one well-known standard source of
information which provides, among other things, for dissolution testing in the
majority
of monographs for such dosage forms.
Current USP dissolution methods most commonly employ a temperature
programmable water bath, maintained at about 37 C., in which sample vessels
are
submerged. These vessels contain a predetermined volume of dissolution media
and
a means to agitate the contents of the vessel. This may be accomplished by
means of
a rotating basket attached to a shaft or with a paddle which is also attached
to a shaft,
CA 02836228 2013-12-13
27
both means are generally described in USP 23rd edition Chapter 711
(Dissolution)
pages 1791-1793. The solid dosage form is placed into the media filled vessel
at time
zero and specific vessel temperature and mixing speeds are maintained. At
fixed time
intervals (e.g. 2, 4, 8 hours, etc.) a small aliquot of sample is taken from
each vessel,
usually by a multi channeled pumping system, and transported to either a
cuvette or a
sample vial for subsequent spectrophotometric or high pressure liquid
chromatography
(HPLC) analysis, respectively. Plotting percentage dissolution of a solid
dosage form
through time results in a dissolution profile.
As it relates to isotretinoin, the United States Pharmacopeia (USP 35)
official
December 1, 2012 describes three test methods for the measurement of
dissolution of
isotretinoin capsules. Unfortunately, these methods do not sufficiently
distinguish
between isotretinoin formulations with and without food effect (table I fig.
1)
These three USP dissolution test methods were used to test isotretinoin
containing drug product sold in the USA:
Absorica (see composition in Table XII) product with no food effect as
described in the product monograph, and
Claravis and/or Amnesteen , which are both products with food effect.
Firstly, the dissolution method USP #1 uses the disintegration equipment. This
is a 2 tier method which comprises a 30 minute capsule soaking in a simulated
gastric
fluid with pepsin followed by a 60 minute disintegration period in a medium
brought to
pH 10 with the addition of NaOH 0.13N. The isotretinoin concentration as a
function of
time is measured by spectroscopy UV at 343 nm. The specification is NLT 80%
(Q) at
90 minutes.
This media while able to totally dissolve the Absorica capsules in 60 minutes
lacks discrimination power as it does not distinguish between isotretinoin
capsules with
food effect (Claravis / Amensteeme) and without food effect (Absorica ).
Secondly, the dissolution method USP #2 is carried out at pH 7.8 buffer
containing 0.5% w/v of surfactant N,N-Dimethyldodecylamine N-oxide using USP
CA 02836228 2013-12-13
28
apparatus #1 (basket) at a speed of 100 rpm and a temperature of 37 C. The
duration
of the test is 90 minutes and the specification is NLT 80% (Q) at 90 minutes.
Samples
are analyzed by HPLC. Upon completion of the test after 90 minutes the
following
observations were made:
1.
Only about 50% for the 10mg capsules and about 40% for the 40mg capsules
of the without-food-effect isotretinoin capsules Absorica are dissolved.
2.
The variability of the results is extremely high: from 4% to 83% for 10mg
Absorica capsules and from 11% to 60% for the 40mg Absorica capsules.
For these reasons it was decided that this method is insufficient for the
testing
of the without-food-effect isotretinoin capsules (Absorica ), namely, the
capsule did
not dissolve during the specified period of time and the extremely large
variability.
Lastly, the dissolution method USP #3 uses borate buffer at pH 8.0, cetrimide
and pancreatin. The test is performed using USP apparatus #2 (paddles) at 75
rpm.
The isotretinoin is determined by HPLC and the test is successful if after 90
min 70%
(Q) is released.
This method is able to dissolve the isotretinoin of the Absorica capsules
within
the specified time but is not able to distinguish between isotretinoin
containing
capsules with food effect (Claravise) and without food effect (Absorica ).
CA 02 8 3 62 2 8 2013-12-13
29
Table XVII. ISOTRETINOIN-CONTAINING CAPSULES USP DISSOLUTION TEST
Summary of CIP Dissolution using Different Dissolution Methods
Food Effect Method USP 1 USP 2 USP 3
Media SGF/NaOH 0.13N Buffer Buffer (borate)
pH 10.0 7.8 8.0
N, N-Dimethyldodecylamine
Surfactant -- Cetrimide
N-oxide
Enzymes Pepsin for 30min -- Pancreatin
Equipment Disintegration Paddle Paddle
Speed 100 rpm 75 rpm
Duration 30 + 60 min 90 min 90 min
Analysis UV->+343 min HPLC HPLC
Specification 080% 0 90 min 080% 0 90 min 070% @ 90 min
Absorica 10 mg -- >53 99
NO
Absorica 40 mg 103 >38 87
Amnesteem 10 mg -- -- 25
Amnesteem 20 mg 91 -- --
YES Claravis 10 mg -- 103 75
Claravis 20 mg -- -- --
Claravis 40 mg 95 93
Conclusions:
Able to distinguish
between:
= .
No No No
Food/Non Food
From those results it is concluded that none of the dissolution tests for
isotretinoin capsules described in the USP are able to differentiate between
the
capsules with and without food effect.
Another dissolution test was performed using a dissolution media claimed by
some to be designed to detect formulations with food effect.
Dissolution tests were performed on Absorica capsules (on isotretinoin-
containing capsules without food effect) using dissolution media simulating
gastro
intestinal fasted and fed states. This study used the dissolution media as
indicated in
Margareth Marque's article: "Dissolution Media Simulating Fasted and Fed
States" as
CA 02836228 2013-12-13
appears in Dissolution Technologies May 2004 Volume 11 Issue 2. The contents
of
this article are incorporated herein in their entirety for its teaching of
dissolution media
and their preparation and use.
Preparation of fasted state simulating intestinal fluid (FaSSIF) and fed state
simulating intestinal fluid (FeSSIF) media.
Fasted State Simulated Intestinal Fluid (FaSSIF)
This media has a pH of 6.50 and an osmolality of about 270 mOsmol/kg.
Preparation of blank FaSSIF
Dissolve 1.74 g of NaOH (pellets), 1.977 g of NaH2PO4.H20 or 17.19 g of
anhydrous NaH2PO4, and 30.93 g of NaCI in 5 L of purified water. Adjust the pH
to
exactly 6.5 using 1 N NaOH or 1 N HCI.
Preparation of FaSSIF
Dissolve 3.3 g of sodium taurocholate in 500mL blank FaSSIF. Add 11.8 mL of
a solution containing 100 mg/mL lecithin in methylene chloride, forming an
emulsion.
The methylene chloride is eliminated under vacuum at about 40 C. Draw a vacuum
for fifteen minutes at 250 mbar, followed by 15 minutes at 100 mbar. This
results in a
clear micellar solution, having no perceptible odor of methylene chloride.
After cooling
to room temperature, adjust the volume to 2 L with blank FaSSIF.
Fed State Stimulated Intestinal Fluid (FeSSIF)
This media has a pH of 5.00 and an osmolality of about 670 mOsmol/kg.
Preparation of blank FeSSIF
Dissolve 20.2 g of NaOH (pellets), 43.25 g of glacial acetic acid, and 59.37 g
of
NaCI in 5 L of purified water. Adjust the pH to exactly 5.0 using 1 N NaOH or
1 N HCI.
Preparation of FeSSIF
CA 02836228 2013-12-13
31
Dissolve 16.5 g of sodium taurocholate in 500 mL of blank FeSSIF. Add 59.08
mL of a solution containing 100 mg/mL lecithin in methylene chloride, forming
an
emulsion. The methylene chloride is eliminated under vacuum at about 40 C.
Draw
vacuum for fifteen minutes at 250 mbar, followed by 15 minutes at 100 mbar.
This
results in a clear to slightly hazy, micellar solution having no perceptible
odor of
methylene chloride. After cooling to room temperature, adjust the volume to 2
L with
blank FeSSIF.
The dissolution of lsotretinoin 40mg Absorica capsules was carried out in
500mL of FaSSIF media and in 1000 mL of FeSSIF media using the USP Apparatus
#2 (Paddles), at 100 rpm and 37 C. Dissolution samples were taken after 1 and
2
hours, and diluted to 50% with Acetonitrile. 90 L were injected into an HPLC
equipped with a UV detector at 353nm, using a 5pm 12.0 cm x 4 mm C18 Column
(like
Lichrocart 100RP-18 endcapped or equivalent). The flow rate was 2.0 mL/min of
mobile phase consisting of Acetonitrile: Water: Glacial Acetic Acid (85: 15:
0.5) at a
temperature of 40 C. The samples were compared to an isotretinoin standard
solution
of known concentration.
CA 02836228 2013-12-13
32
Table XVIII. Results of Absorica Capsules in fasted simulating media
Time (min) Unit 1 Unit 2 Unit 3 Mean RSD
60 13.8 11.4 9.4 12 19
120 15.7 16.4 13.2 15 11
The fasted simulating media (FaSSIF) only dissolves 15% of Absorica 40 mg
capsules after 2 hours.
Table XIX. Results of Absorica Capsules in fed simulating media
Time (min) Unit 1 Unit 2 Unit 3 Mean RSD
60 12.1 12.4 12.6 12 2.1
120 17.1 16.9 20 18 9.8
The Fed simulating media (FeSSIF) only dissolve 18% of Absorica 40 mg
capsules
after 2 hours.
From this experiment it is concluded that the simulated fasted and fed
dissolution
media are insufficiently capable of determining the food dependence of an
isotretinoin-
containing drug products without food effect, such as Absorica , since media
is
unable to dissolve said Absorica 40 mg capsules.
All these trials demonstrate that for isotretinoin drug products none of the
dissolution
test methods available to one skilled in the art are able to distinguish
between
formulation with and without food effect.
The use of the dissolution method of Example 3 is of great importance for the
optimization of dosing conditions and product formulation since it can
differentiate
between isotretinoin formulations with or without significant food effect.
In addition, this biorelevant dissolution test could be used to assess
bioequivalence of
post-approval formulation changes in drug product form.
