Prevalence of Substandard Amoxicillin Oral Dosage Forms in the National Capital District of Papua New Guinea

Abstract

Antibiotics are commonly reported as being substandard or falsified in low- to middle-income countries, having potential to contribute to the development of antimicrobial resistance and drug-resistant infections. Amoxicillin, used to treat a number of infections and listed by the WHO as an essential medicine, presented as a good drug candidate for this study. We aimed to measure the prevalence of substandard and falsified amoxicillin oral products (tablets, capsules, and suspensions) in the National Capital District of Papua New Guinea (PNG). These oral products were surveyed in 2018 and 2019 from retail pharmacies, private and public health facilities, and the Area Medical Store, representing more than 90% of licensed medicine outlets. The product packaging was visually inspected, and the samples were analyzed for amoxicillin content using a validated high-performance liquid chromatography method. Although no falsified products were identified, 15% of the 190 products analyzed contained substandard amounts of amoxicillin. Quality varied with the dosage form (P = 0.002), with capsules exhibiting the lowest incidence of substandard content (4% in 2019) and tablets collected in 2018 experiencing the highest failure rate (50%). Suspension (40%) quality was compromised by failure to achieve homogeneity on reconstitution. A higher incidence of substandard content (P = 0.002) was associated with one major retail group. Routine testing of medicines by resource-poor countries is often unachievable, leading to the circulation of poor quality drugs, which is a global public health concern. Our study highlighted that substandard amoxicillin oral products are indeed prevalent in the NCD of PNG.

Investigation of the Quality of the 12 Most-Used Antibiotics Available in Retail Private Pharmacies in Rwanda

“…In this study, 36.8% of substandard antibiotics were amoxicillin, which was also the most-represented antibiotic (26.7%) and its overall failure rate was estimated at 11.3%. A lower percentage failure rate was found in Ghana and Nigeria in 2015 [26], while a percentage failure rate higher than the one found in our study was observed in Papua New Guinea in 2021 [25] and the Lao People's Democratic Republic [10]. The percentage failure for doxycycline in this study was different from the situation in the Democratic Republic [15,22].…”

“…As previously reported in different studies carried out in other LMICs [22][23][24][25], the results obtained from the visual inspection did not reveal any counterfeit/ falsified medicines. Our study failed to obtain genuine samples from manufacturers to compare to our samples, as was also the case in a study conducted in Ghana, Nigeria and the United Kingdom by Fadeyi Ifeyinwa et al in 2015 [26].…”

“…Ifeyinwa Fadeyi et al found that 60% of co-trimoxazole tablets purchased in Ghana and Nigeria in 2015 did not meet quality requirements [26]. Other authors found substandard antibiotics in different LMICs [25].…”

Audit of the Physico-Chemical Quality of Amoxicillin Based Drugs Marketed in Senegal

“…This assay showed that the samples have amoxicillin levels which are normal because they belong to the compliance interval which is [90% to 120%]. This result is different from that of Sherryl G. Robertson who found that 15% (28/190) did not meet pharmacopoeial requirements [18]. On the other hand, the Ecumenical Pharmaceutical Network, which found in one of the studies that 83 of the 92 samples (90.21%) were in complete compliance with the requirements of the pharmacopoeia [19].…”