Quality of amoxicillin formulations in some Arab countries

The problem of counterfeit and substandard drugs is recurrent in developing countries where antibiotics account for the majority of such products. The aim of this study was to investigate the quality of locally produced and imported amoxicillin products on the Lebanese, Jordanian, Egyptian and Saudi markets.

One hundred and eleven samples of amoxicillin capsules and suspensions purchased from retail pharmacies were analysed for their drug content by a validated chromatographic method in order to verify if they complied with pharmacopeial requirements. Suspensions were analysed for their drug content immediately after reconstitution as well as 7 or 14 days later according to the expiry date.

Fifty-six per cent of amoxicillin capsules did not meet the United State Pharmacopeia (USP) requirements and most had amounts bordering the lower limit. Individual average values as low as 59% of the label claim were detected. Eight per cent of the samples of suspensions gave measurements outside pharmacopeial limits. Furthermore, after 7 or 14 days, 38% of the samples were outside the pharmacopeial limits. All the European brands met the pharmacopeial limits except for one.

Our results reveal the high incidence of substandard drugs on some Arab market where several factors might jeopardize the quality status of medicines: lack of effective quality assurance system during manufacture in both Arab and export countries, and uncontrolled storage conditions, especially unsuitable pharmacy premises. Use of substandard antibiotic preparations increases the risk of therapeutic failure and the emergence of drug-resistant microorganisms.