Quality Attributes and In Vitro Bioequivalence of Different Brands of Amoxicillin Trihydrate Tablets

Abstract:

Bacterial resistance and antibiotic drug effectiveness can be related to administering

generic products with a subtherapeutic dose or poor in vivo drug release. The aim of this study

was to investigate whether locally marketed amoxicillin tablets have the required chemical and

physical attributes, including in vitro bioequivalence performance. Five generic products (T1, T2,

T3, T4, and T5) containing combination of amoxicillin trihydrate and potassium clavulanate as 1 g

strength present in immediate release tablets were compared to the reference listed drug product

Augmentin® (R) for weight variation, friability, resistance to crushing, and chemical content of

amoxicillin. Difference (f 1) and similarity (f 2) factors were calculated to assess in vitro bioequivalence

requirements. The tablets from different products have shown compliance with the pharmacopeial

requirements of the performed tests. The measured resistance to crushing of tablets did not influence

the dissolution time. Three generic products released more than 85% of amoxicillin by the first 15 min

as did the reference product and were considered as bioequivalent products. T1 and T4 had f 1 values

of 16.5% and 25.4% respectively and their f 2 values were 44.5 and 34.6 respectively, indicating failure

to meet in vitro bioequivalence requirements. Tablet formulations can play an important role in

achieving bioequivalence. Independent investigations such as this study serve as an important tool

to reveal possible inferior or noncompliant products that may find their way to the market.

Keywords: amoxicillin tablets; bioequivalence; weight variation; friability; chemical content;

difference factor; similarity factor; HPLC Analysis