ABSTRACT
OBJECTIVE:To optimize the formula of Captopril timing osmotic pump tablets. METHODS:Using accumulative release rate (Q) as index, single factor test was used to investigate the effects of blocking layer coating weight gain, semipermeable membrane coating weight gain,the type of polyepoxide (PEO),the amount of PEO (3 × 105) and HPMC in drug bearing layer,the amount of PEO (7 × 106) and NaCl in booster layer on drug release of Captopril timing osmotic pump tablets. Based on single factor investigation,using comprehensive score of release behavior(L)as index,the amount of PEO(3×105)and HPMC in drug bearing layer,the amount of PEO(7×106)and NaCl in booster layer as factors,L9(43)orthogonal test was used to optimize the formula of tablet core validation test was conducted. RESULTS:The optimal formula of tablet core included PEO(3× 105)71 mg and HPMC 15 mg in drug bearing layer,PEO(7×106)61 mg and NaCl 18 mg in booster layer,coating weight gain 7％ and semipermeable membrane coating weight gain 10％ in blocking layer. The osmotic pump tablet prepared by optimized formula released after 4 h;in vitro drug release regression equation was Q=5.118t-21.441(R2=0.9956),which was in line with zero-order release characteristics. CONCLUSIONS:The optimal formula is stable,feasible and controllable in quality,and can provide reference for further development of Captopril timing osmotic pump tablets.