RESUMO
Objective: To evaluate the quality consistency of four domestic nifedipine sustained release tablets by dissolution test and virtual bioequivalence study by GastroPlus software.Methods: The dissolution curves of the four preparations were determined with the methods described in Japanese orange book and Chinese Pharmacopeia.The f2 factor of dissolution curves was calculated to compare the similarity.The in vitro dissolution data of the original preparation were combined with GastroPlus software to obtain the simulated in vivo absorption curves which were correlated with the actual concentration-time curves.The suitable dissolution medium was selected to evaluate the quality of domestic nifedipine sustained release tablets according to the better in vivo-in vitro correlation (IVIVC).The simulated in vivo absorption parameters obtained from the dissolution data combined with GastroPlus software were used to conduct the virtual bioequivalence study of domestic nifedipine sustained release tablets compared with the original products.Results: The f2 similar factors of the four domestic nifedipine sustained release tablets compared with the original preparation were all less than 50.Compared with that from the method in Japanese orange book, the correlation between the dissolution profiles in vitro and in vivo of original nifedipine sustained release tablets obtained from the method in Chinese Pharmacopoeia was better.The deviation between the simulated Cmax and AUC0-∞ values of the four test tablets and the measured values of the original preparation was within the range of ±20%.Conclusion: The dissolution curves of the four domestic nifedipine sustained release tablets are not similar to that of the original preparation, however, the four preparations are all bioequivalent to the original preparation according to the simulated absorption parameters based on the dissolution method in Chinese Pharmacopeia and GastroPlus software.
RESUMO
Objective:To compare the drug release of nifedipine sustained-release tablets from four manufacturers to evaluate the intrinsic quality. Methods:The drug release rate was determined by UV respectively with pH 1. 2 HCl solution, pH 4. 0 sodium ace-tate buffer, pH 6. 8 phosphate buffer and water as the dissolution medium. The dissolution curves were compared by f2 factor. Results:The drug release rate of nifedipine sustained-release tablets from the four manufacturers all met quality standard of our country, al-though the dissolution curves in the different dissolution medium was various. Conclusion:There are differences in intrinsic quality a-mong the nifedipine sustained-release tablets from the four manufacturers. The dissolution examination standard should be improved fur-ther.
RESUMO
OBJECTIVE:To improve the testing method of the related substances in nifedipine sustained-release tablets (Ⅰ).METHODS:The chromatographic condition was in line with the "State Drug Standard".In computing the contents of foreign substances,the standard of "it is negligible if the peak area of foreign substances was less than 10% of the peak area of Nifedipine in the standard solution" was improved to be "it is negligible if the peak area of foreign substances was less than 2%of the peak area of Nifedipine in the standard solution".RESULTS:The contents of the foreign substances determined in accordance with the "National Drug Standard" weresignificantly different from those determined by the improved method (0.00%,0.08%,0.29%,0.14 % vs.0.10%,0.21%,0.51%,0.27%,respectively).CONCLUSION:The improved method can help improve the standard drug quality in that the contents of the foreign substances can be strictly kept under control.