| JP2009184924 | COMPOUND FOR BIOLOGICAL REAGENT |
| WO/2001/004124 | OXATHIEPINO[6,5-b]DIHYDROPYRIDINES, AND RELATED COMPOSITIONS AND METHODS |
| WO/2006/044826 | THIOPHENS AND THEIR USE AS ANTI-TUMOR AGENTS |
KIM, Nam Ho (1 Hyundai Apt, Eunhaeng-dongJungwon-gu, Seongnam-si, Gyeonggi-do 462-150, 01-1409, KR)
LEE, Jin Young (202 Sungwon Jutaek Na-dong, Jeongja-dong 527-1 Jangan-gu, Suwon-si, Gyeonggi-do 440-300, KR)
LEE, Nam Kyu (123-108 Jugong Apt, 333 Cheoncheon-dongJangan-gu, Suwon-si, Gyeonggi-do 440-330, KR)
OH, Joon Gyo (1 Hanil Town, Jowon-dongJangan-gu, Suwon-si, Gyeonggi-do 440-709, 53-1704, KR)
SHIN, Ji Young (1 Han River Samsung Apt, Tojeong-dong Mapo-gu, Seoul 121-060, 02-1601, KR)
KIM, Tae-Kon (3 Byucksan Apt, Jeongja 2-dong 886-1, Jangan-gu, Suwon-si, Gyeonggi-do 440-842, 48-1104, KR)
YOON, Mi-Sun (401 1561-4, Sa 1-dongSangnok-gu, Ansan-si, Gyeonggi-do 426-894, KR)
SUNG, Jin-Heung (1615-803 Sarang Maeul Apt, Sang-dong Wonmi-gu Bucheon-si, Gyeonggi-do 420-709, KR)
LEE, Yoon-Jung (601-203 Gahyeon Sinan Apt. Gugal-dong, Giheung-gu Yongin-si, Gyeonggi-do 446-951, KR)
PARK, Yeo-Jin (618-21 Myeonmok 7-dong, Jungnang-gu, Seoul 131-828, KR)
UM, Key An (102-305 Hanil Town, Jowon-dongJangan-gu, Suwon-si, Gyeonggi-do 440-709, KR)
KIM, Jae-Sun (15/5 Seryu 2-dong 1146-3, Gwonseon-gu Suwon-si, Gyeonggi-do 441-880, KR)
KIM, Nam Ho (1 Hyundai Apt, Eunhaeng-dongJungwon-gu, Seongnam-si, Gyeonggi-do 462-150, 01-1409, KR)
LEE, Jin Young (202 Sungwon Jutaek Na-dong, Jeongja-dong 527-1 Jangan-gu, Suwon-si, Gyeonggi-do 440-300, KR)
LEE, Nam Kyu (123-108 Jugong Apt, 333 Cheoncheon-dongJangan-gu, Suwon-si, Gyeonggi-do 440-330, KR)
OH, Joon Gyo (1 Hanil Town, Jowon-dongJangan-gu, Suwon-si, Gyeonggi-do 440-709, 53-1704, KR)
SHIN, Ji Young (1 Han River Samsung Apt, Tojeong-dong Mapo-gu, Seoul 121-060, 02-1601, KR)
KIM, Tae-Kon (3 Byucksan Apt, Jeongja 2-dong 886-1, Jangan-gu, Suwon-si, Gyeonggi-do 440-842, 48-1104, KR)
YOON, Mi-Sun (401 1561-4, Sa 1-dongSangnok-gu, Ansan-si, Gyeonggi-do 426-894, KR)
SUNG, Jin-Heung (1615-803 Sarang Maeul Apt, Sang-dong Wonmi-gu Bucheon-si, Gyeonggi-do 420-709, KR)
LEE, Yoon-Jung (601-203 Gahyeon Sinan Apt. Gugal-dong, Giheung-gu Yongin-si, Gyeonggi-do 446-951, KR)
PARK, Yeo-Jin (618-21 Myeonmok 7-dong, Jungnang-gu, Seoul 131-828, KR)
UM, Key An (102-305 Hanil Town, Jowon-dongJangan-gu, Suwon-si, Gyeonggi-do 440-709, KR)
[CLAIMS]
[Claim 1]
An inclusion complex containing clopidogrel having superior storage stability
comprising clopidogrel represented by the formula (1) below and β-cyclodextrin at
an equivalence ratio from 1 : 2.0 to 1 : 2.5:
CO 2 CH 3
[Claim 2]
A method of preparing an inclusion complex containing clopidogrel
comprising:
1) dissolving clopidogrel in a mixture of an organic solvent and an acidic
solution or in distilled water;
2) stirring the resultant at 30 to 70 0 C, while adding 2.0 to 2.5 equivalents of β-
cyclodextrin based on 1 equivalent of clopidogrel;
3) neutralizing the resultant product with an alkali metal hydroxide at 0 to 50 o 'rC-;- and
4) filtering, washing and drying the resultant product to obtain an inclusion
complex. [Claim 3]
The method according to claim 2, wherein said clopidogrel is a clopidogrel base
or a clopidogrel salt.
[Claim 4]
The method according to claim 3, wherein said clopidogrel salt is clopidogrel
bisulfate, clopidogrel hydrochloride, clopidogrel bromide or clopidogrel
benzenesulf onate .
[Claim 5]
The method according to claim I 1 wherein a water-soluble polymer is added in
step 2).
[Claim 6]
An antiplatelet agent composition comprising the inclusion complex according
to claim 1 as an active ingredient. |
[DESCRIPTION]
[Invention Title]
INCLUSION COMPLEX CONTAINING CLOPIDOGREL WITH IMPROVED
STORAGE STABILITY
[Technical Field]
The present invention relates to an inclusion complex containing clopidogrel
with superior storage stability, more particularly to a pharmaceutically stable and
suitable inclusion complex obtained by reacting S-(+)-clopidogrel [methyl (+)-(S)-α-
(o-chlorophenyl)-6,7-dihydrothieno[3,2-c]pyridin-5(4H)-ac etate] represented by the
formula (1) below with β-cyclodextrin at a specific equivalence ratio, and an
antiplatelet agent composition comprising the same as an active ingredient:
CO 2 CH 3
[Background Art]
According to recent researches, it has been reported that clopidogrel is more
effective than aspirin in blocking platelet aggregation even at lower dosage, with
less gastrointestinal distress. Hence, it makes a very effective antiplatelet agent.
Clopidogrel is marketed under the trade name Plavix. A tablet contains about 98
mg of clopidogrel hydrogen sulfate, which includes 75 mg of clopidogrel base as an
active ingredient.
European Patent No. 0281459 proposes the use of an inorganic salt of (S)-(+)-
clopidogrel, more specifically (S)-(+)-clopidogrel hydrogen sulfate for
pharmaceutical preparations. Since the active ingredient clopidogrel base is an oily
liquid, it has to be transformed into a pharmaceutically acceptable salt for simple
pharmaceutical preparations. The above patent mentions, along with hydrogen
sulfate, taurocholate, hydrochloride and bromochloride as salts of clopidogrel
acceptable for pharmaceutical preparations. The patent also mentions organic salts
of clopidogrel, but the organic salts are non-crystalline and/ or hygroscopic and
difficult to purify.
Other patents published thereafter state that particularly a sulfonate has
stability almost comparable to that of the hydrogen sulfate.
WO 2004/072084 and 2004/072085 suggest that sulfonate, particularly
benzosulfonate, which is described in European Patent No. 0281459 as unsuitable for
pharmaceutical preparations, is acceptable for pharmaceutical preparation under a specific condition. It is mentioned that as crystalline clopidogrel besylate, a solvate
form including toluene or dioxane solvent is preferable and that non-crystalline
clopidogrel besylate is obtained by further drying and removing the solvent.
WO 2005/103059 and Korean Patent Publication No. 2005-0099445 mention a
novel crystalline salt clopidogrel napadisilate, a polymorphic crystal form, a hydrate
and a solvate thereof, which are optically pure, thermally stable and non-
hygroscopic. However, such a sulfonate salt of clopidogrel has very low solubility
as compared to existing hydrogen sulfate and the clopidogrel base may be
precipitated as oil in aqueous solution. Further, optical stability tends to be poor.
An especially important factor in the clopidogrel salt is hygroscopicity. High
hygroscopicity may affect physical and chemical properties of active ingredient and
excipient and cause problems in drug formulations. Accordingly, the control of
hygroscopicity in pharmaceutical preparations is an important factor, along with
packaging or storage. In particular, the clopidogrel base is an oily liquid and even
the hydrogen sulfate, which is known as the most preferable salt form, may be
hydrolyzed or racemized by external environment to produce impurities. The most
commonly produced impurities are the hydrolysis product (2) of the methyl ester
and the R-(-)-isomer of clopidogrel (3) resulting from racemization:
(2)
An adequate control is required in preparing and processing pharmaceuticals in
large quantity to reduce these impurities below a certain level. Also, the packaging
and storage need to be managed properly.
[Disclosure]
[Technical Problem]
The present inventors have found that an inclusion complex prepared by
reacting clopidogrel with cyclodextrin at a specific equivalence ratio has outstanding
stability as free base, not as acid addition salt, and properties appropriate for drug
manufacture.
[Technical Solution]
Accordingly, an object of the present invention is to provide an inclusion
complex containing clopidogrel having superior storage stability and a use thereof.
[Advantageous Effects]
The inclusion complex containing clopidogrel according to the present
invention has outstanding storage stability against temperature and humidity.
Therefore, it can be stored for a long period of time, easily prepared into preparation
forms and endure the temperature and humidity of the production process without
being decomposed.
[Description of Drawings]
Figure 1 illustrates the inclusion of one clopidogrel molecule with two β-
cyclodextrin molecules.
Figure 2 shows the powder X-ray diffractogram of the clopidogrel inclusion
complex prepared in Example 1.
Figure 3 compares the dissolution rate of the tablet containing clopidogrel
inclusion complex prepared in Example 11 with that of a commercially available
tablet.
[Best Mode]
In an aspect, the present invention provides an inclusion complex containing clopidogrel having superior storage stability comprising clopidogrel represented by
the formula (1) below and β-cyclodextrin at an equivalence ratio from 1 : 2.0 to 1 : 2.5,
and a preparation method thereof.
CO 2 CH 3
composition comprising the inclusion complex as an active ingredient.
Hereunder is given a more detailed description of the present invention.
The present invention relates to a pharmaceutically stable and suitable inclusion
complex obtained by reacting S-(+)-clopidogrel [methyl (+)-(S)-α-(o-chlorophenyl)-
6 / 7-dihydrothieno[3 / 2-c]pyridin-5(4H)-acetate] represented by the formula (1) with
(3-cyclodextrin at a specific equivalence ratio, and an antiplatelet agent composition
comprising the same as an active ingredient:
First, the preparation procedure of the inclusion complex containing clopidogrel
according to present invention will be described in detail.
1) Clopidogrel is dissolved in a mixture of an organic solvent and an acidic
solution or in distilled water. The acidic solution may be an organic or inorganic
acid. Preferably, hydrochloric acid, sulfuric acid, phosphoric acid or acetic acid is
used. The organic solvent may be at least one selected from acetone, ethanol,
isopropanol and butanol.
The clopidogrel used in the present invention may be a clopidogrel free base or
a clopidogrel salt. The clopidogrel salt may be clopidogrel bisulfate, clopidogrel
hydrochloride, clopidogrel bromide or clopidogrel benzenesulfonate. Further,
other forms of clopidogrel, for example, a mixture (premix or adsorbate) of a
clopidogrel free base with a pharmaceutically acceptable additive or excipient, may
be used. The substance remaining without being dissolved is removed by filtering,
and the filtrate, or an acidic solution of clopidogrel, is used in later steps.
2) Stirring is performed at 30 to 70 0 C, preferably at 40 to 60 0 C, while adding
β-cyclodextrin to the solution prepared in step 1). When the temperature is below
30 0 C, more solvent is needed to dissolve cyclodextrin and inclusion efficiency may
decrease. And, when the temperature exceeds 70 0 C, clopidogrel may be
decomposed.
3) The reaction mixture is neutralized by adding a base. The base may be an
alkali metal hydroxide, e.g., sodium hydroxide, potassium hydroxide, barium
hydroxide or calcium hydroxide. The neutralization is performed at 0 to 50 0 C,
more preferably at 10 to 40 0 C. When the neutralization temperature is lower than
0 0 C, impurities other than the inclusion complex or unincluded cyclodextrin may be
precipitated concurrently due to overcooling. And, when the temperature exceeds
50 0 C, the amount of impurities may increase.
4) The reaction mixture is filtered, washed and dried to obtain the wanted
inclusion complex. The final inclusion complex can be obtained in high yield by
washing the filtrate several times with a small quantity of water and drying.
In step 2), a water-soluble polymer compound may be added. Preferably, the
water-soluble polymer compound is at least one selected from polyethylene glycol
(PEG), polyvinylpyrrolidone (PVP), carboxymethyl cellulose (CMC), hydroxypropyl
cellulose (HPC), hydroxymethyl cellulose (HMC), hydroxyethyl cellulose (HEC),
hydroxypropyl methyl cellulose (HPMC) and hydroxypropyl ethyl cellulose (HPEC).
The β-cyclodextrin used in the present invention includes derivatives of β-
cyclodextrin, as well as β-cyclodextrin itself. Preferably, β-cyclodextrin or a
derivative thereof having a cavity diameter ranging from 6.0 to 6.5 A is selected.
Preferably, β-cyclodextrin is used in an amount from 2.0 to 2.5 equivalents,
based on 1 equivalent of clopidogrel. The present inventors examined inclusion
efficiencies at various equivalence ratios of clopidogrel and β-cyclodextrin. It was
found that the inclusion efficiency is maximized and a stable inclusion complex is
obtained when β-cyclodextrin is used in an amount of 2.0 or more equivalents, based
on 1 equivalent of clopidogrel. As can be seen from Figure 1, which illustrates the
inclusion of one clopidogrel molecule with two β-cyclodextrin molecules, each part
of the thienopyridone and the chlorobenzene portions of clopidogrel is included as a
rather stable structure by one β-cyclodextrin molecule. Accordingly, an optimal
stability is attained when the proportion of clopidogrel and β-cyclodextrin is
maintained at 1 : 2.
However, when β-cyclodextrin is used in an amount exceeding 2.5 equivalents,
there is a problem that the tablet volume increases. In order to limit the content of
β-cyclodextrin required to obtain the inclusion complex to 2.5 equivalents or smaller,
based on 1 (molar) equivalent of clopidogrel, the present inventors adjusted the
amount of β-cyclodextrin, the amount of distilled water, and the amount of the base
required for neutralization, and could attain a high inclusion efficiency with an
equivalence ratio from 1 : 2.0 to 1 : 2.5.
The powder X-ray diffractogram (PXRD) of the clopidogrel inclusion complex
shows a characteristic diffraction pattern. The PXRD was taken using M18XHF22
(Mac Science) under the condition of 20 mA, 40 kV and 203-35 °.
Thus obtained inclusion complex of the present invention has outstanding
storage stability against high temperature and humidity. Therefore, it can be stored
for a long period of time, easily prepared into preparation forms and endure the
temperature and humidity of the production process without being decomposed.
The present inventors performed studies in order to find a better clopidogrel
composition than existing clopidogrel salts, using β-cyclodextrin. As a result, they
developed a novel inclusion complex of clopidogrel having superior physical and
chemical properties and pharmaceutical availability under a specific reaction condition. Whereas only limited acidic salts were obtained as stable salt of
clopidogrel base, which is an oily liquid, in the prior art, the present invention has
proven that a composition suitable for pharmaceutical preparations can be obtained
through inclusion. Unexpectedly, thus obtained inclusion complex has very
superior stability without any noticeable hygroscopicity, and is thus suitable for
pharmaceutical preparations.
The requirements needed for an ideal clopidogrel containing composition are as
follows.
First, it needs to be non-hygroscopic. The present inventors have prepared
various clopidogrel salts. Since the clopidogrel base is an oily liquid, the reaction
itself was not easy. In many cases, salt was not precipitated at all or, even when it
did, the salt was discolored by absorbing moisture. Further, when clopidogrel
absorbs moisture, impurities including hydrolysis product [formula (2)] and R-
isomer [(formula 3)] may be generated. Thus, the inclusion composition needs to
be non-hygroscopic.
Second, superior stability over a long period of time is required. Superior
physical and chemical properties are advantageous not only in formulation studies,
but also in packaging, storage and production. The present inventors measured
storage stability of the inventive composition over a long period of time. They also
observed the generation of hydrolysis products and R-isomers, which are important impurities needed to be controlled, and the content changes thereof, and compared
them with those of known salts. Further, they tested the stability of the inclusion
complex of clopidogrel and β-cyclodextrin under various harsh conditions and
compared the result with those of known salts.
Third, a good handlability is required for large-scale preparation and
formulation studies. For this purpose, the composition needs to be non-
hygroscopic and have good stability, as mentioned above. Also, it needs to be easy
to prepare and purify.
The inclusion complex containing clopidogrel according to the present
invention satisfies all these requirements, and provides very good yield and purity.
The present invention further provides an antiplatelet agent comprising the
inclusion complex as an active ingredient.
The antiplatelet agent may be prepared into an oral administration form,
preferably tablet, hard capsule, powder or granule, by mixing the inclusion complex
with a pharmaceutically acceptable diluent, binder, disintegrant, lubricant, coating
agent, etc. Examples of the pharmaceutically acceptable diluent include non¬
crystalline cellulose, corn starch, and so forth. The binder may be selected from a
commonly used binder, including povidone, copovidone, cellulose, and the like.
Preferably, the disintegrant may be croscarmellose sodium, sodium starch glycolate,
carboxymethylcellulose calcium, etc. The lubricant may be selected from a
commonly used lubricant, including sodium stearyl fumarate, magnesium stearate,
talc, glyceryl fatty acid ester, glycerol dibehenate, etc. And, the pharmaceutically
acceptable coating agent includes polyvinyl alcohol, hydroxypropyl methyl cellulose,
methylcellulose, ethylcellulose, and the like.
Effective dose of the clopidogrel containing inclusion complex may vary
depending on the age of patient, severity of disease, and the like. Normally, based
on the clopidogrel base, a daily dose of 30 to 300 mg, preferably 30 to 150 mg, more
preferably 75 mg, may be employed.
[Mode for Invention]
The present invention is explained in more detail with reference to the
following examples. However, they should not be construed as limiting the scope
of the present invention.
Example 1: Preparation of inclusion complex of clopidogrel and β-cyclodextrin
1.6 g (5 mmol) of clopidogrel base was dissolved in 5 mL of acetone. 0.3 mL of
strong sulfuric acid was added, and stirring was performed slowly at room
temperature for 5 minutes. While slowly stirring at 60 0 C after adding 160 mL of
distilled water, 12.8 g of β-cyclodextrin was added and stirring was performed at 60
0 C for 3 hours. After adding 2 mL of 2.5 N NaOH solution and stirring at room temperature for 3 hours, the resultant solid was filtered and washed with 16 mL of
distilled water. The product was dried in vacuum for 20 hours to obtain 7.79 g of
white solid compound. The compound was identified as an inclusion complex of
clopidogrel and β-cyclodextrin by HLPC analysis. X-ray diffraction measurement
showed characteristic diffraction angles 20 at 5.96 ° and 12.98 ° [Figure 2].
Clopidogrel : β-cyclodextrin = 1 : 2.0 (equivalence ratio)
1 H-NMR (300 MHz, DMSOd 6 ) δ (ppm): 7.57-7.60 (m, IH), 7.48-7.52 (m, IH),
7.36-7.41 (m, 2H), 7.26 (d, IH, J = 5.1 Hz), 6.76 (d, IH, J = 5.1 Hz), 5.74 (d, 14H), 5.67
(d, 14H), 4.86 (s, IH), 4.83 (d, 14H), 4.45 (t, 14H), 3.70 (s, 3H), 3.50-3.69 (m, 58H), 3.26-
3.38 (m, 36H), 2.77-2.84 (m, 4H)
Example 2: Preparation of inclusion complex of clopidogrel and β-cyclodextrin
2.1 g (5 mmol) of clopidogrel bisulfate was dissolved in 5 mL of distilled water.
195 mL of distilled water was further added at room temperature to completely
dissolve the clopidogrel bisulfate. Then, after adding 12.8 g of β-cyclodextrin and
gradually heating to 60 0 C, stirring was performed for 3 hours. After gradually
cooling to room temperature, adding 2 mL of 2.5 N NaOH solution and stirring at
room temperature for 5 hours, the resultant solid was filtered and washed with 20
mL of distilled water. The product was dried in vacuum for 20 hours to obtain 7.80
g of white solid compound. The compound was identified as an inclusion complex
of clopidogrel and β-cyclodextrin by HLPC analysis.
Clopidogrel : β-cyclodextrin = 1 : 2.05 (equivalence ratio)
Example 3: Preparation of inclusion complex of clopidogrel and β-cyclodextrin
2.1 g (5 mmol) of clopidogrel bisulfate dissolved in 5 mL of distilled water was
added to a suspension of 12.8 g of β-cyclodextrin and 195 mL of distilled water.
After gradually heating to 60 0 C, stirring was performed for 3 hours. Then, after
gradually cooling to room temperature, adding 2 mL of 2.5 N NaOH solution and
stirring at room temperature for 5 hours, the resultant solid was filtered and washed
with 20 mL of distilled water. The product was dried in vacuum for 20 hours to
obtain 8.30 g of white solid compound. The compound was identified as an
inclusion complex of clopidogrel and β-cyclodextrin by HLPC analysis.
Clopidogrel : β-cyclodextrin = 1 : 2.07 (equivalence ratio)
Examples 4: Preparation of inclusion complex of clopidogrel and β-cyclodextrin
1.6 g (5 mmol) of clopidogrel base was dissolved in 5.0 mL of acetone. After
adding 0.3 mL of strong sulfuric acid, stirring was performed slowly at room
temperature for 5 minutes. After adding 200 mL of aqueous 1 % HPMC solution
and adding 14.08 g of β-cyclodextrin while stirring slowly at 60 0 C, stirring was
performed at 60 0 C for 3 hours. Then, after adding 2 mL of 2.5 N NaOH solution
and stirring at room temperature for 3 hours, the resultant solid was filtered and
washed with 20 mL of distilled water. The product was dried in vacuum for 20
hours to obtain 9.53 g of white solid compound. The compound was identified as
an inclusion complex of clopidogrel and β-cyclodextrin by HLPC analysis.
Clopidogrel : β-cyclodextrin = 1 : 2.09 (equivalence ratio)
Examples 5: Preparation of inclusion complex of clopidogrel and β-cyclodextrin
1.6 g (5 mmol) of clopidogrel base was dissolved in 5.0 mL of acetone. After
adding 0.3 mL of strong sulfuric acid, stirring was performed slowly at room
temperature for 5 minutes. After adding 200 mL of aqueous 1 % PVP solution and
adding 14.08 g of β-cyclodextrin while stirring slowly at 60 0 Q stirring was
performed at 60 0 C for 3 hours. Then, after adding 2 mL of 2.5 N NaOH solution
and stirring at room temperature for 3 hours, the resultant solid was filtered and
washed with 20 mL of distilled water. The product was dried in vacuum for 20
hours to obtain 10.72 g of white solid compound. The compound was identified as
an inclusion complex of clopidogrel and β-cyclodextrin by HLPC analysis.
Clopidogrel : β-cyclodextrin = 1 : 2.11 (equivalence ratio)
Test Example 1: Stability test
Stability test was performed for the clopidogrel inclusion complexes prepared in
Examples 1 to 5 and clopidogrel bisulfate (Dr. Reddy's), under the condition of 40 0 C
and 75 % RH. The amount of impurities - that is, hydrolysis product [formula (2)]
and racemization product R-isomer [formula (3)] - was measured and is given in
Table 1 below.
Chiral HPLC was performed to identify the impurities and optical purities,
under the following conditions:
Stationary phase: Ultron ES-OVM column, 5 μm (4.6 mm X 150 mm i.d.)
Mobile phase: 25 % acetonitrile + 75 % 0.01 M potassium dihydrogen phosphate
solution (v/v)
Flow rate: 1 mL/min
Column temperature: 17 0 C
UV detection wavelength: 220 nm
Injection volume: 10 μL
Table 1 - Stability test (after 3 weeks)
As shown in Table 1, the inclusion complexes prepared in Examples 1 to 5
exhibited better stability than clopidogrel bisulfate (Plavix), with fewer impurities.
Test Example 2: Blood level measurement after oral administration to rats
The inclusion complex prepared in Example 1 (Compound 1) and clopidogrel
bisulfate (Compound 2) were orally administered to Sprague-Dawley rats weighing
250 to 270 g at a dose of 30 mg/kg (base). After 0.5, 1, 2, 4, 6, 8, 10 and 24 hours,
blood sample were taken using a pipette treated with heparin. The blood sample
was centrifuged at 12,000 rpm for 2 minutes. To 0.1 niL of thus obtained blood
plasma, 100 μL of internal standard solution was added, and 0.6 mL of diethyl ether-
hexane (80:20, v/v) mixture solvent was added. After extracting by shaking for
about 5 minutes, the sample was centrifuged at 2,000 g for 10 minutes. The organic
solvent layer was transferred to a clean test tube, and the organic solvent was
evaporated under nitrogen flow. 50 μL of the mobile phase was added to the
remainder, and 20 μL was taken and injected into the HPLC column. Liquid
chromatography was performed, and blood level was measured from the peak area
ratio of clopidogrel to the internal standard.
Table 2 - Blood levels and pharmacokinetic parameters after oral administration
to rats at a dose of 30 mg/kg
As seen in Table 2, the inclusion complex of the present invention (Compound
1) exhibited comparable to or better pharmacokinetic parameters compared to
Compound 2, following oral administration to rats.
Examples 6-9: Preparation of film-coated tablet containing inclusion complex
The ingredients and excipients listed in Table 3 below were prepared into
granules using a high-shear mixer (SM-5, Sejong Machinery). Thus obtained
granules were passed through a 30 mesh sieve, mixed with a lubricant, and
compressed using a single punch press (Erweka) to produce round tablets. The
rounded tablets were coated with coating base dissolved in purified water using a
coating machine (SFC-30N, Sejong Machinery) to produce film-coated tablets.
Table 3
Examples 10-11: Preparation of film-coated tablet containing inclusion complex
The ingredients and excipients of Examples 6 and 8 in Table 3 were prepared
into granules using a fluidized-bed granulator (DPL-I, Mendel Korea) The
temperatures at the inlet and outlet of the granulator were around 65 0 C and around
40 0 C, respectively. The spraying quantity and the spraying pressure were adjusted to 10 mL/min and 0.8 kg/ cm 2 , respectively. Thus obtained granules were passed
through a 30 mesh sieve, mixed with a lubricant, and compressed using a single
punch press (Erweka) to produce round tablets. The rounded tablets were coated
with coating base dissolved in purified water using a coating machine (SFC--30N,
Sejong Machinery) to produce film-coated tablets.
Test Example 3: Stability test
The clopidogrel inclusion complex tablets prepared in Examples 6, 8 and 10 and
commercially available Plavix tablet (Sanofi-Synthelabo Korea) were subjected to
stability tests. The test conditions were the same as described in the ICH
(International Conference on Harmonization) guideline. That is, a long-term test
was performed at 25 0 C and 60 % RH, and an accelerated test was performed at 40 0 C
and 75 % RH as open test.
Analysis was performed according to USP (United States Pharmacopoeia) 3215-
3216. Most of the impurities were ascertained to be hydrolysis product (RRT 0.5,
impurity A) and R-enantiomer (RRT 2.0, impurity C) in terms of RRT (relative
retention time). USP recommended that impurity A, impurity C, unknown
impurity and total impurity should be below 0.2 %, 1.0 %, 0.1 % and 1.2 %,
respectively. The increased amounts of the impurities were calculated relative to
initial values, and provided in Table 4 below.
Table 4 - Stability test (open test, 3 weeks)
As seen in Table 4, the tablets prepared in Examples exhibited superior stability
than commercially available Plavix tablet, with less increase in impurities A and C.
Test Example 4: Dissolution test
The clopidogrel inclusion complex containing tablet prepared in Example 8 and
commercially available Plavix 75 mg tablet (Sanofi-Synthelabo Korea) were
subjected to the dissolution test according to method II paddle test as described in
the Korean Pharmacopoeia. The dissolution test was performed at pH 2.0 as
recommended in USP 29, and media was 1000 mL and paddle rotation speed was 50
rpm.
4 mL of the sample was taken at 5, 10, 15, 30 and 45 minutes, and filtered
through 0.45-μm membrane filter. The solution was analyzed by absorption spectrophotometry at a detection wavelength of 240 nm. As shown in Figure 3, the
tablet prepared in accordance with the present invention showed comparable
dissolution rate to that of commercially available Plavix.
[Industrial Applicability]
As set forth above, the inclusion complex containing clopidogrel according to
the present invention has outstanding storage stability against high temperature and
humidity. Therefore, it can be stored for a long period of time, be easily prepared
into preparation forms and endure the temperature and humidity of the production
process without being decomposed. When compared with existing drugs, it is
expected to provide a longer shelf life and better quality of drugs, while maintaining
dissolution rate.
The present invention has been described in detail with reference to preferred
embodiments thereof. However, it will be appreciated that those skilled in the art,
upon consideration of the disclosure, may make modifications and improvements
within the scope and spirit of the invention.
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