Amoxicillin Quality and Selling Practices in Urban Pharmacies and Drug Stores of Blantyre, Malawi

Abstract

This study evaluated a newly developed paper analytical device (PAD) for screening amoxicillin samples in Blantyre urban townships. Covert shoppers attempted to buy amoxicillin from a geographically stratified selection of private pharmacies (N = 22 out of 26) and drug stores (N = 23 out of 103) in the township area. According to the PAD results, all 42 samples obtained by the shoppers contained amoxicillin and none contained suspicious filler materials. Next, the products were assayed using high-performance liquid chromatography. Consistent with the PAD results, all samples contained the correct amount of amoxicillin with no unexpected ingredients. However, one sample was purchased as amoxicillin and contained that ingredient, but was packaged in capsules that are normally used to package ampicillin. Almost every sample failed a simple packaging analysis. Nine in 10 samples were missing their original packaging and/or inserts (52.4% repackaged capsules and 35.7% repackaged blister packs). Only 33.3% of the packages had expiry dates, 16.7% had batch numbers, and 47.6% had the manufacturer's name. Dispensing practices were likewise unsatisfactory. Ninety-five percentage of the sellers sold the amoxicillin without a prescription, even though this medicine is regulated as prescription-only in Malawi. Although the chemical analysis showed that amoxicillin quality was good, our market survey revealed poor adherence to prescription-only medicine dispensing of antibiotics, which threatens antimicrobial stewardship efforts. Furthermore, the wide prevalence of repackaging deprives medicines of important information needed during patient's use, regulatory investigations, and pharmacovigilance reporting.

Figure 1.

Sample high-performance liquid chromatography chromatogram for amoxicillin.

Figure 2.

Paper analytical device (PAD) operation and results. (A) Powder from capsule is applied to paper. (B) PAD is activated by dipping in water. (C) Colors develop. (D) Total time required is 7 minutes. (E) Image of PAD sample run in Malawi. (F) PAD standard image or “bar code” for good amoxicillin dosage form; critical lanes are B and C (green), F (dark green), and K (bright red). (G) PAD standard image for water blank. This figure appears in color at www.ajtmh.org.

Figure 3.

Repackaging of antibiotics was common. Almost all samples of amoxicillin were dispensed either as loose capsules in a plastic bag or as blister-packed capsules with no box or insert. The rightmost bag shows a product that was sold as amoxicillin but is packaged in red and black capsules that are normally used for ampicillin. This product was confirmed to be amoxicillin, so it is not a falsified product. This figure appears in color at www.ajtmh.org.

Figure 4.

Amoxicillin purity (90–120% active pharmaceutical ingredient [API] content meets United States Pharmacopeia requirement for purity) and cost (Malawi Kwacha per gram). U.S. buyer (Caucasian and therefore easily identifiable as non-Malawian customer) and Malawi buyer received the same drug quality at the same price from 42 vendors in the Blantyre metro region. Box shows middle two quartiles, whiskers show range of points within (1.5 × interquartile range), and outliers are shown as crosses. This figure appears in color at www.ajtmh.org.