the soft capsule of butylphthalide according to the present invention is composed of a capsule wall material and a drug - containing oil , wherein the drug - containing oil is essentially composed of butylphthalide and a vegetable oil in an preferable weight ratio of about 1 : 1 - 8 , more preferably about 1 : 2 - 5 , most preferably about 1 : 3 . 5 . furthermore , as an antioxidant , about 0 - 0 . 2 % of dibutylcarboxyl toluene relative to the weight of drug - containing oil may also be added into the drug - containing oil . preferably , the vegetable oil is peanut oil , soybean oil , corn oil , and sesame oil . most preferably , the vegetable oil is soybean oil . the capsule wall material is essentially composed of a capsule wall matrix , a plasticizer and water , wherein the capsule wall matrix is preferably gelatin , and the plasticizer is preferably glycerol . the following examples are provided for a particular purpose of further illustrating technical features of the present invention , and should not be construed as any limitation to the present invention . components of gelatin solution : 100 g of gelatin , 30 g of glycerol , 130 g of water and 200 mg of ethyl p - hydroxybenzoate . gelatin was added into an appropriate amount of water to permit it to absorb water and swell . glycerol , ethyl p - hydroxybenzoate and remaining water were added into a melting tank and heated to 70 - 80 ° c . after uniformly mixed , the swollen gelatin was added , agitated , melted and incubated for 1 - 2 hours . the resulting mixture was thus kept standing to allow foams floating up . then foams were removed by filtering through clean white cloth , and the temperature was kept for use . the gelatin solution was generally formulated at 2 . 8 - 3 . 2 rpm . preparation of drug - containing oil : 100 g of butylphthalide was weighed and thoroughly mixed with 350 g of clear soybean oil , to obtain the drug - containing oil . compression of soft capsules : the gelatin solution and drug - containing oil were supplied into an automated rotary capsule machine . the temperature was kept at 40 - 50 ° c ., and soft capsules were compressed , each of which contains 450 mg of drug - containing oil . the soft capsules , compressed with the drug - containing oil by such a ratio , were tested and showed to have moderate shape and size and good content homogeneity . results of the test were as following : the preparation procedure was the same as that described in example 1 , except that no vegetable oil was added in the step of preparing drug - containing oil . each of the soft capsules finally compressed contains 100 mg of drug - containing oil . preparation of gelatin solution : 100 g of gelatin , 40 g of glycerol , 120 g of water and 200 mg ethyl p - hydroxybenzoate were used . the steps for preparing gelatin solution were the same as that described in example 1 . preparation of drug - containing oil : 225 g of butylphthalide was weighed and thoroughly mixed with 225 g of clear peanut oil , to obtain the drug - containing oil . compression of soft capsules : the procedure was the same as that described in example 1 , except that each of the soft capsules finally compressed contains 200 mg of drug - containing oil . the soft capsules , compressed with the drug - containing oil by such a ratio , were tested , and results were as following : the preparation procedure was the same as that described in example 1 , except that in the step of preparing the drug - containing oil , 56 . 25 g of butylphthalide was weighed and thoroughly mixed with 393 . 75 g of clear peanut oil . each of the soft capsules finally compressed contains 800 mg of drug - containing oil . the soft capsules , compressed with the drug - containing oil in such a ratio , were tested , and results were as following : preparation of gelatin solution : 100 g of gelatin , 20 g of glycerol , 80 g of water and 200 mg of ethyl p - hydroxybenzoate were used . the steps for preparing gelatin solution were the same as that described in example 1 . preparation of drug - containing oil : 45 g of butylphthalide was weighed and thoroughly mixed with 405 g of clear peanut oil , to obtain the drug - containing oil . compression of soft capsules : the procedure was the same as that described in example 1 , except that each of soft capsules finally compressed contains 1000 mg drug - containing oil . the preparation procedure was the same as that described in example 1 , except that in the step of preparing the drug - containing oil , 90 g of butylphthalide was weighed and thoroughly mixed with 360 g of clear soybean oil . each of soft capsules finally compressed contains 500 mg of drug - containing oil . the preparation procedure was the same as that described in example 1 , except that in the step of preparing the drug - containing oil , 40 . 91 g of butylphthalide was weighed and thoroughly mixed with 409 . 09 g of clear soybean oil . each of soft capsules finally compressed contains 1100 mg of drug - containing oil . the preparation procedure was the same as that described in example 1 , except that in the step of preparing the drug - containing oil , 50 g of butylphthalide was weighed and thoroughly mixed with 400 g of clear soybean oil . each of soft capsules finally compressed contains 900 mg of drug - containing oil . the preparation procedure was the same as that described in example 1 , except that in the step of preparing the drug - containing oil , 150 g of butylphthalide was weighed and thoroughly mixed with 300 g of clear soybean oil and 0 . 45 g of dibutylcarboxyl toluene as an antioxidant . each of soft capsules finally compressed contains 300 . 3 mg of drug - containing oil . a ) disintegration time : samples prepared in example 1 were provided . time required for complete disintegration of each soft capsule was tested in accordance with the disintegration time assay ( pharmacopoeia of p . r . china , the edition of 2000 , part ii , appendix va ), with 1000 ml of diluted hydrochloric acid ( 9 to 1000 ) as solvent , the temperature was controlled at 37 ± 1 ° c ., the lift - and - drop rate of 30 to 32 times per minute , and with a baffle plate when operated . time required by complete disintegration of each soft capsule was investigated . the disintegration time should not be over 1 hour , and should comply with the corresponding regulations . b ) related materials : tests were performed according to high performance liquid chromatography ( pharmacopoeia of p . r . china , the edition of 2000 , part ii , appendix vd ). testing method : appropriate amount of the content of capsules was sampled , appropriate amount of chloroform was added into it to dissolve , and then methanol was added to supplement the volume . the resulting solution was diluted with methanol to formulate a testing solution containing 0 . 5 mg of the content per milliliter . appropriate amount of butylphthalide control was separately and precisely weighed , dissolved with methanol and formulated into a control solution containing 15 μg of butylphthalide per milliliter . 20 μl of control solution was accurately injected into the liquid chromatograph and tested according to the method known in the art . the detection sensitivity was adjusted in order to make the peak of the main fraction as high as 10 - 20 % of full range . 20μl of testing solution was accurately taken and tested according to the same method . chromatographic spectrum was recorded for two times of the retention time of the main fraction peak in chromatography . if impurities presented in chromatographic spectrum , the area sum under the peak of each impurity ( with the exception of the peak of solvent ) was calculated , should be not more than the area of that of control solution ( 3 . 0 %). c ) determination of butylphthalide content : the content was determined by high performance liquid chromatography ( pharmacopoeia of p . r . china , the edition of 2000 , part ii , appendix vd ). chromatographic condition and system suitability test : silica gel bonded with octodecyl silane was used as packing , methanol - water ( 65 : 35 ) was used as mobile phase with a flow rate of 1 . 0 ml / min . the detection was performed at the wavelength of 280 nm . theoretical plate number of butylphthalide should be not less than 1500 . the degree of separating butylphthalide from impurities should comply with related regulations . preparation of control solution : 50 mg of butylphthalide was precisely weighed and placed into a 50 ml measuring flask . the weighed butylphthalide is dissolved with methanol and diluted to the predetermined value of scale , and mixed uniformly . 5 ml of resulting solution was precisely taken and placed into a 50 ml measuring flask , diluted with methanol to the predetermined value of scale , and thus the control solution was obtained . preparation of test solution : appropriate amount of the content in capsules ( approximately 50 mg of butylphthalide ) was taken and precisely weighed . the weighed content is placed into a 50 ml measuring flask , dissolved with appropriate amount of chloroform , diluted with methanol to the predetermined value of scale and thoroughly mixed . 5 ml of resulting solution was precisely taken and placed into a 50 ml measuring flask , diluted with methanol to the predetermined value of scale , and thus the test solution was obtained . testing method : 20 μl of control solution and 20 μl of test solution separately were precisely sampled and injected into the liquid chromatograph , and then tested according to the method known in the art . the chromatographic spectrum was recorded , and the content of butylphthalide ( c 12 h 14 o 2 ) was calculated with peak area in accordance with external standard method . although frequently soft capsules have the problem of unqualified disintegration due to the prolonged time of storage , as shown in the accelerating test and long period test on the present soft capsules , the wall of the soft capsule aged quickly with heating treatment and disintegration time changed significantly but still remained less than 60 minutes , which complied with related regulations of pharmacopoeia of p . r . china , the edition of 2000 . various parameters , such as product appearance , the content and related materials and the like all complied with the standard , with a valid period up to 2 years .
the present invention discloses a novel soft capsule of butylphthalide and a process for preparing the same . the soft capsule of butylphthalide is composed of a capsule wall material and a drug - containing oil , wherein the drug - containing oil is essentially composed of butylphthalide and a vegetable oil as the diluent in a weight ratio of about 1 : 0 ˜ 10 . the capsule wall material is composed of a capsule wall matrix , a plasticizer and water in a weight ratio of 1 : 0 . 2 ˜ 0 . 4 : 0 . 8 ˜ 1 . 3 . the soft capsule of butylphthalide described in the present invention can mask the strong and special flavour of butylphthalide , and overcome the difficulties associated with formulating oily active ingredient into other oral formulation . the disintegration time of the soft capsule satisfies the requirement of pharmacopoeia of p . r . china .