Study of the Polymorphs and Dissolution of Cilnidipine Tablets

OBJECTIVE To investigate the difference of generic drugs and the original drug by researching the polymorphs and dissolution. METHODS Reference Raman spectra of the 2 crystal forms of cilnidipine were established; then the polymorphs of the cilnidipine tablets from different manufacturers were analyzed, and a dissolution method was established to distinguish the different samples. RESULTS The polymorph of samples from manufacture A and manufacture B were polymorph α. The polymorph of samples from manufacture C and original drug were amorphous form. The dissolution method (0.5% SDS pH 6.8 phosphate buffer, 900 mL, 75 r·min^-1) was established and could distinguish the different samples. CONCLUSION There exist certain differences between generic drugs and the original drug in terms of dissolution and the polymorphs.