Note: Descriptions are shown in the official language in which they were submitted.
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Vancomycin Purification Improvement and Product
Vancomycin is a glycopeptide antibiotic
substance produced by fermentation of Nocardia
orientalis (previously designated Streptomvces
orientalis~, a microorganism isolated from soil obtained
from Indonesia and India. Like most antibiotics derived
from fermentation, vancomycin is a multi-factor complex
of several closely related and chemically similar
compounds. The preparation of the material is described
in detail in U.S. Patent No. 3,067,099. Vancomycin is
used commercially primarily as an antibacterial agent,
although it also is effective as a ruminant feed utili-
zation enhancer; see U.S. Patent No. 3,816,618.
The preparation of commercial vancomycin hasrequired a multi-step process involving fermentation
followed by rather extensive isolation and purification
steps. The fermentation whole broth generally is
filtered to remove solids and mycelia and the filtrate
containing the soluble antibiotic is passed over a low
cross-linked cation exchange resin which retains the
antibiotic activity. The resin eluate containing
vancomycin is next treated with decolorizing charcoal
and the soluble vancomycin is then isolated as an
insoluble copper complex. The copper complex is finally
treated with hydrogen sulfide under acidic conditions to
solubilize the vancomycin, which can be isolated as a
free base by suitable pH adjustment. The free base is
employed in formulations for oral administration to
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animals, and may be used directly or converted to a
derivative such as the hydrochloride salt for formu-
lations as an injectable.
The commercial production of vancomycin
suffers in several respects. The use of cupric salts in
the isolation process requires the subsequent use of an
agent such as hydrogen sulfide to spring the copper
complex and to precipitate soluble salts of copper as
insoluble sulfides or the like. This has resulted in a
vancomycin product that sometimes has an offensive odor
and is generally somewhat colored. Also, the multi-step
isolation and purification process has suffered from
product loss at each stage, such that the overall yield
of vancomycin free base has been on the order of only
thirty percent.
The present invention provides a new salt form
of vancomycin that is crystalline and that can be
isolated directly from an aqueous solution of relatively
crude vancomycin, for instance from fermentation broth.
No salt forms of vancomycin have heretofore been
obtainable in crystalline form. The new crystalline
form of this invention is stable for prolonged periods,
and can be employed directly in pharmaceutical
preparations. The invention provides an improvement in
the process for isolating vancomycin by eliminating the
need to form a vancomycin copper complex, improving
overall yields, and providing a product having improved
pharmaceutical properties.
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The new crystalline co~position provided by
this invention is the diphosphate salt of vancomycin.
The compound can be isolated from an acidic aqueous
solution of vancomycin, and generally exists as a
hydrate. The degree of hydration varies depending upon
the extent to which the compound i subjected to drying,
but normally the salt will be isolated with from o to
about 10 moles of water of hydration. A preferred
compound of the invention is crystalline vancomycin
diphosphat,e decahydrate. The vancomycin diphosphate
provided by this invention is a highly crystalline
material having good stability. When hydrated the
compound of the invention exhibits the following X-ray
powder diffra~ion properties when measured with a
114;6 mm Debye-Scherrer camera using nickel-filtered
copper radiation of 1.5418 A:
~6~81~C~
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Relative
Spacing, d: Intensities,I/Il:
16.52 1.00
12.36 .30
10.28 .50
a.ss 75
7.97 .50
7.41 .20
-10 6.76 .20
6.24 .20
5.61 ~5~
5.34 .50
4.96 .40
4.73 .20
4.44 .50
4.26 . 50
3.98 .40
3.75 .40
3.S5 .50
3.35 .30
3.15 VW
3.01 VW
2.81 VW
2.66 VW
Note: VW means very weak
The improvement in the process for isolating
and purifying vancomycin provided by this invention is
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accomplished by converting vancomycin from an aqueous
solution, for example a fermentation aqueous broth, to a
diphosphate salt and isolating the salt by filtration.
In practice, vancomycin whole broth is filtered at an
alkaline pH of about 8.0 to about 10. Conventional
diatomaceous filter aids such as"Celite"(Johns Manville,
Inc.) and the like generally are employed to facilitate
removal of solid impurities and fermentation mycelia.
The filtrate is then passed across an ion-exchange resin
such as'~onac X-236" a low cross-linked polysty~ene-
divinylbenzene sodium cation resin, and the vancomycin
is adsorbed thereon. The vancomycin is eluted from the
resin by washin~ the resin with water and eluting with
an aqueous alkaline solution of about pH 9.0 to about pH
11Ø A typical solvent for elution is aqueous sodium
hydroxide of pH about 10.0 to about 11Ø The alkaline
resin eluate containing vancomycin is neutralized and
the activity is re-adsorbed onto a non-functional resin,
for example commercial"~iaion HP-20"resin or the like.
The loaded resin is eluted with a suitable solvent,
preferably an aqueous alcohol solution such as about 3
to about 30% (v/v) aqueous ethanol or isopropanol. If
desired, the aqueous alcohol can be acidified, for
example by addition of phosphoric acid, thereby gen-
erating the vancomycin diphosphate during elution of thenon-functional resin.
The eluate containing the vancomycin generally
is concentrated by removal of a portion of the solvent,
for instance by evaporation under reduced pressure. The
solution ideally is concentrated until it contains about
* Txademark for diatonaceous earth
** Trademark
*** Trademark
X - 5 6 01 - 6 ~ ? ~
250 to about 285 Ing of vancomycin per ml of solution.
The concentrated eluate is acidified with a phosphate
source to pH of about 2.0 or less, for illstance by
addition of aqueous phosphoric acid. Additional
phosphate anions can be added to the solution if
desired, for irlstance by adding an alkali metal salt of
dihydrogen phosphate such as sodium or potassium di-
hydrogen phosphate. The amount o such added phosphate
source is not critical, but generally will be from about
10 to about 20 percent by weight of the vancomycin
present in the solu~ion. Upon cooling the aqueous acid
solution to about 0 to about 20C, the vancomycin
diphosphate crystalline foxm of this invention precip-
itates and can be recovered by filtration. The product
can be further,purified if desired by conventional means
such as,washing the c~ystals with cold water or a
solvent such as an alcohol, or by recrystallization from
common solvents such as water, ethanol and the like.
The new crystalline salt forms of vancomycin as
described above, and also the process for isolating
lS vancomycin from aqueous solution which comprises converting
the vancomycin to a crystalline diphosphate salt and
separating said salt rom the solution, are also disclosed
and are claimed, in Canadi~n Patent Application No. 469,358
filed December S, 1984, of which the present applicatlon i9 a
divisional.
The present invention, in a further aspect, resldes
in a process for preparing vancomycln hydrochlorlde which
comprises reacting vancomycin diphosphate with a hydrogen
chloride source.
The preparation of the new crystalline vanco-
2G mycin diphosphate provided by this i~vention and theoperation of the process improvement is more fully
illustrated by the following detailed examples.
Example 1
To a stirred suspension of lO g of vancomycin
in 15 ml of water were added 2 ml o~ 85% w/v aqueous
phosphoric acid. All particles went into solution. The
solution was cooled to 0C for sixteen hours. The
crystalline precipitate that formed was collected by
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filtration, washed with 20 ml of isopropanol and then
with 20 ml of diethyl ether, and air dried ~o give 7.5 g
of vancomycin diphosphate, mp 194C (dec).
A sample of the crystalline product was dried
at 120C (weight loss was 11.55% suggesting ten moles of
water of crystallization) and the sample was submitted
for elemental analysis.
Analysis calculated for C66H75C12NgO24 2 H3PC4
Theory: C, 48.18; H, 4.96; N, 7.66; Cl, 4.31;
0, 31.12; P, 3.77.
Found: C, 47.98; H, 5.19; N, 7.41; Cl, 4.20;
o, 31.04; P, 3.77.
ExamPle 2
Vancomycin whole aqueous fermentation broth
was made alkaline to pH 9 by addition of 6N sodium
hydroxide. The aqueous alkaline mixture was filtered,
and the filtrate was adjusted to pH 7 and filtered
again. The filtrate was passed over an Ionac X236,
sodium form resin column, which was washed with water
and then eluted with pH 10 borate buffer. The activity
in the neutralized eluate was adsorbed on "Diaion HP-20"** resin.
The loaded resin was washed with water and then eluted
with a solution of O.lN phosphoric acid and 10% (v/v)
aqueous isopropyl alcohol. The fractions containing
vancomycin were combined (2300 ml) and concentrated
under reduced pressure to a volume of 65 ml. The
* Trademsrk
** Trademark
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solution was shown by bioassay to contain 258 mg/ml of
vancomycin. The solution was acidified to pH 2 by
addition of 6N phosphoric acid. The acidic solution was
stirred at 25C while 2.5 g of potassium dihydrogen
phosphate were added portion-wise. The acidic solution
was cooled to about 5C for eighteen hours. The
crystalline precipitate was collected by filtration and
washed with 26 ml of cold (5C) 2% w/v aqueous potassium
dihydrogen phosphate, with 13 ml of cold (5C) deionized
water, and finally with 26 ml of cold (5C) isopropyl
alcohol. The crystalline product was dried in vacuum at
42C for twelve hours to provide 13.5 g (76.6% yield) of
vancomycin diphosphate.
Example 3 ~ -
The vancomycin diphosphate crystal form
provided by this invention is a highly crystalline solid
when hydrated that is stable over prolonged periods of
time. The stability of bulk samples of vancomycin
diphosphate was determined by ~-reparing three lots of
the compound by the method of Example 2. Samples of the
three individual lots were stored at 21-23C in poly-
ethylene containers. Various physical parameters of
each of the three lots were analyzed at zero, six,
twelve and eighteen months. The results of the study
are presented in the following Table:
- 9 -
~'
o oo ~ c`
J CJ Cl O ' O ~ ~ ~ o o ~ ~) o ~o) U1
¢ ~J O ~!~rl ~~ ~1 ~1 _I
~r~
~ r~
l ~ ~ eU ~ ~ _1~ ~7 00 _1~ ~0~ 0 C
C ~ J
¢ u ~ E ~
o
¢
~ ~ r~
E~ ~I C~ O~ ~ O C~ O O~
c c` --l oo ~ ~ o r~
O~ ~ ~d
~~ -
e ~ u~ O u~ Oo ~ oO u~ ~ ~ .-
o cr~ o ~1
~o `O o ~
o_, _I
Z
~_
o
I ~O O O O ~O O ~D O O O ~ O _~
Coi o o~ oo ~1 ~ oo ~u) 1--~ o E o
z_I ~ ~ ~7 ~ ~ ~ n'' ~ ~ X
o ~,1
,t~o~o ~oo ~ o
: x ~ ~ u
u
c o~
e~
, o
C~ o o o
. ~
. . .
X-5601 -10-
The data in the above table demonstrates that the vanco-
mycin diphosphate of this invention is quite stable,
retaining more than about 90% ~f its initial biological
actlvity over a twelve month period.
The crystalline diphosphate provided by this
invention can be employed as an intermédiate in the
synthesis of other vancomycin salt forms, and the
compound can be formulated with conventional exciplents
and carriers and employed in the treatment of diseases
of bacterial origin.
The crystalline diphosphate salt can be
readily formulated for convenient oral or parenteral
administratlon for therapeutic and prophylactic
treatment of bacterial infections. For example, the
salt can be admixed with conventional pharmaceutical
carriers and excipients and used in the form of tablets,
capsules, elixirs, suspensions, syrups, wafers and the
like. The compositions comprising vancomycin
diphosphate will contain from about 0.1 to about 90% by
weight of the active compound, and more generally about
lO to about 30%. The compositions may contain common
carriers and excipients such as corn starch or gelatin,
lactose, sucrose, microcrystalline cellulose, kaolin,
mannitol, dicalcium phosphate, sodium chloride and
alginic acid. Disintegrants commonly employed in
formulations of this invention include croscarmellose
sodium, microcrystalline cellulose, corn starch, sodium
starch glycolate and alginic acid. Tablet binders tha~
can be included are acacia, methylcellulose, sodium
carboxymethylcellulose, polyvinylpyrrolidone (Povidone),
* Trademark
G~
X-5601
hydroxypropylmethylcellulose, sucrose, starch and
ethylcellulose. Lubrlcants, glidants and antladherents
that can be employed include magnesium stearate or other
metallic stearates, stearic acid, silicone fluid, talc,
waxes, oils and colloldal slllca. Flavoring agents such
as peppermint, oll of wintergreen, cherry flavoring or
the like can also be employed. Illustrative of
formulations suitable for oral administration are the
following examples:
'10
Example 4
Preparation of tablets contalning 250 mg of
vancomycin as the free base
Ingredient. ` Weight
Vancomycin Diphosphate
(prepared by the method
of Example 2) 282.5 mg
Microcrystalline Cellulose 101.5 mg
Croscarmellose sodium 12.0 mg
Povidone" (TM) 12.0 mg
Magnesium stearate3.0 mg
Stearic acid 4.0 mg
Purified water 0.16 ml
Vancomycin diphosphate, a portion of the
microcrystalline cellulose and a portion of the
croscarmellose sodium are added to a suitable container
u~
X-5601 -12-
~ and blended until homogeneous. A solution of Povidone
- in water is prepared. The Povidone solution is added to
the blended powders. The resulting mixture is
granulated, si~ed if necessary and dried. Remaining
microcrystalline cellulose and croscarmellose sodium are
added to the dried granulation. The powders are
blended. ~agnesium stearate a~d stearic acid are added
and the mixture blended. The resulting powder blend is
compressed into tablets with a theoretical weight of
415 mg. Each tablet contains vancomycin diphosphate
equivalent to 250 mg of vancomycin free base.
Example 5
Preparation of capsules of vancomycin
diphosphate
Ingredient Weiqht
Vancomycin Diphosphate 282.5 mg
Corn Starch Flowable Powder 117.65 mg
Silicone Fluid 350 Centistokes 2.75 mg
Corn Starch 147.1 mg
Blend vancom~cin diphosphate, starch flowable powder,
silicone fluid 350 centistokes and starch powder in a
suitable mixer until homogeneous. Fill into appropriate
size hard gelatin capsules to a net fill weight of
550 mg. Each capsule contains vancomycin diphosphate
equivalent to 250 mg o~ vancomycin active base.
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Example 6
Vancomycin diphosphate li~uid ~ormulation
Inqredient Weight
Vancomycin Diphosphate 5 g
Red Dye 10 mg
Cherry Flavor 50 mg
Sodium Lauryl Sulfate 1.5 mg
Sucrose 62 g
Add the sucrose to a suitable blender. Add a premix
containing a portion of the sucrose as a powder along
15 . with the red dye, cherry flavor, and the sodium lauryl
sulfate. Prior to use, 60 ml of water is added to the
dry blend in a bottle. The bottle is shaken until the
contents dissolve in the water. Each 5 ml will contain
250 mg of vancomycin diphosphate.
..
,
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Example 7
Vancomycin diphos~hate suspension
(Ready-to-use)
Ingredient Weight
Vancomycin Diphosphate 5 g
Butylparaben 20 mg
Red Dye lO mg
Cherry Flavor 50 mg
Thixin R 400 mg
Sucrose Powder 30 g
Fractlonated Coconut Oilq.s. to 100 ml
Heat the fractionated~coconut oil. Add while mixing the
butylparaben and the "Thlxm R"*. Cool to room temper-
ature. Add the sucrose powder, red dye, cherry flavor,
and the vancomycin diphosphate. Pass through a colloid
mill. Each S ml will contain 250 mg of vancomycin
diphosphate.
As pointed out above, the vancomycin diphos-
phate crystal form of this invention can be converted to
other vancomycin derivatives, for example to other salt
forms such as the hydrochloride salt. Vancomycin
diphosphate can be dissolved in an aqueous acid solution
and the corresponding acid addition salt recovered, or
it can be reacted with an aqueous alkaline solution to
provide the free base, which is subsequently reacted
with a mineral acid or organic acid to give the
* Trademark
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X-5601 -lS-
corresponding acid addition salt. A preferred method
for accomplishing such conversion employs an ion
exchange resin as exemplified below.
Example 8
An ion exchange resin ("~lite IRA-45") was washed with
5% wt/v aqueous sodium hydroxide and then with 5% v/v
aqueous hydrochloric acid to pH 1.2. The resin was
placed in a 1.7 cm x 66 cm glass column. A solution of
81 g of vancomycin diphosphate (prepared as described in
Example 2) in 812.5 ml of deionized water was passed
over the ion exchange resin at a flow rate of 13 ml per
minute. The eluate was collected and the resin was
washed with water. The eluate and wash were combined,
neutralized to pH 3.5 by addition of the free base form
of "Amberlite IRA-45"* resin in 180 ml of water. me resin was
removed by filtration and the filtrate (1200 ml) was
analyzed. The concentration of vancomycin hydrochloride
was determined by ultraviolet analysis at 280 nm and
shown to be 51.17 mg/ml. The filtrate thus contained
61.4 g (94% yield) of vancomycin hydrochloride. Further
purification and lyophilization provided vancomycin
hydrochloride powder.
In a further embodiment of this invention
vancomycin diphosphate is employed as an antibacterial
agent in the treatment of diseases of bacterial origin.
The compound can be suitably formulated and administered
* Trademark for a weakly basic anion exchange resin.
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X-5601 -16-
orally or parenterally to an animal suffering from a
bacterial infection. The compound can also be used
prophylactically and administered to subjects snspected
of developing a bacterial infection. Vancomycin di-
phosphate is particularly effective against strains ofgram-positive micro-organisms such as streptococci,
staphyloccoci, Clostridium difficile and the like.
In practicing the antibacterial method o this
invention, vancomycin diphosphate will be suitably
formulated and administered in an effective amount of
about 0.5 to about 25 mg/kg. A typical daily dose for
an adult human will be from about 250 mg to about l.0 g.
The exact amount of compound to be administered may of
course vary depending upon the particular condition and
subject being treated and related factors.
The vancomycin diphosphate of this invention
can additipnally be employed for improving the
efficiency of feed utilization by ruminants. The
compound can be formulated as an animal feedstuff or
premix and administered to ruminants at the rate of
about 20 to about 40 grams of active ingredient per ton
of feed. Typical animals subject to such treatment
include cattle raised for meat production, sheep and
related ruminants.
