RESEARCH ON NIFEDIPINE PATCH

The feasibility of matrix dispersion- type nifedipine patch was verified and an HPLC method for the determination of nifedipine level both in vitro and in vivo was established.It was found that both the two formulations of the patch (R₂ with azone as penetration enhancer, R₁ without azone) provided zero order kinetics of permeation, the rates of skin permeation were different at <10.25 and> 10.25h, R₁ was 2.63 and 1.1 μg/cm²· h ; R₂ was 4.30 and 1.54μg/cm²· h. The release profiles of nifedipine from R₂ were found to follow a linear Q vs t^1/2 relationship with a release flux of 68.91μg/cm²·h^1/2. The plasma concentration vs time profiles of nifedipine in healthy subjects, each receiving two patches (36×2 cm²), were investigated. A steady state plasma level within therapeutic concentration window was obtained from 1.5 h to 24. 5 h. Several quality tests of the patch were evaluated in this research.