後発医薬品採用のための品質評価

―マレイン酸エナラプリル錠における検討―

抄録

A comparative study was carried out to evaluate the quality of one brand name tablet (A) and five generic tablets (B∼F) containing 5 mg of enalapril maleate (ENA). Tablet quality was evaluated based on such characteristics as content, impurities, dissolution profile, hygroscopic properties, and stability. In the purity test, we measured the quantities of degradation products such as diacid compound (DA) and diketopiperazine compound (DKP) and in the hygroscopicity test, the weight and hardness of the tablets without blister packaging was measured initially and after 2 weeks and 4 weeks of storage at 0%, 43%, 75% and 93% relative humidity (RH). To test stability, we measured the quantities of ENA, DA, and DKP in tablets stored without blister packaging at 40°C and 75% RH for 12 weeks.
The ENA content in all preparations was approximately equal to the indicated content. Initially, DA was not detected in any of the preparations. About 0.3% DKP was detected in preparation B and C. The dissolution profiles of all generic tablets were similar to those of the brand name tablet. For preparations A, B, and D, a marked increase in tablet weight and decrease in tablet hardness was observed with increasing RH. In the stability test, the remaining ENA content in preparations A, B, and D after 12 weeks was significantly lower than the initial content. The DA content in preparations A and D had increased markedly after 12 weeks and so had the DKP content in preparation B.
Our study showed that the quality of the generic tablets C, E, and F was comparable to that of brand name tablet A with respect to stability and resistance to humidity. We conclude that if generic manufacturers continue to produce such high quality drugs, this will lead to greater confidence in their effectiveness and an increase in their use in the clinical setting.