Comparative Study on the Adequacy of Information and Dissolution Test between Original and Generic Drugs (I), Glibenclamide and Gliclazide / 医薬品情報学

ABSTRACT

  Generic drugs have received much attention especially from an economic point of view.  In Japan, the form of medical prescriptions has been revised twice in recent two years to disseminate generic drugs in recent two years.  The pharmacists are irresistibly required the detail knowledge of various generic drugs.  However, sufficient information on generic drugs has not always been provided in comparison with the original drugs.  This study intends to reveal such problems with the generic drugs.  Glibenclamide and gliclazide were selected as the model drugs for this study because these two drugs are often taken together with supplements.  Two approaches were used to compare the original drug and the corresponding generic drugs.  The first approach concerns the amount of information as well as the quality of the information that is provided from manufacturers.  The second approach concerns the physicochemical properties, dissolution test and hardness test.  Regarding the pharmacokinetic information in the package insert of glibenclamide, six generic drugs among eleven samples provided sufficient information while four samples seemed insufficient.  As for gliclazide, three samples among eight did not provide AUC and the time dependence of the blood concentration curve.  The results of the dissolution test revealed that all generic drugs satisfied most of the equivalence to the original drug except for one generic glibenclamide.  On the other hand, different behaviors in the swelling property and the time required to completely disperse were observed.  Two samples for glibenclamide and four samples for gliclazide required a fairly long time to completely disperse.  Irregular and significant variations were observed in the hardness test.  The difference in the dissolution process and hardness test suggested the different drug formulations among manufacturers.