Quality of antidiabetic medicines in 13 sub-Saharan African countries: a cross-sectional survey

Abstract

Background: The burden of diabetes is rising dramatically in low- and middle-income countries. The menace of substandard and falsified drugs constitutes a major hazard that compromises healthcare. The DIABDAF study aimed to assess the quality of routinely used antidiabetic drugs including oral drugs and insulins in sub-Saharan Africa.

Methods: Drugs were collected in 13 sub-Saharan African cities in licensed and unlicensed places of sales between February 2020 and March 2023. Chemical analyses were conducted blindly in a public laboratory following recommended good laboratory practices. Drug quality was classified based on the ratio of measured to expected active ingredient dosage: 95-105% as good (A), 85-94·99% or 105·01-115% as low (B), and below 85% or above 115% as very low (C). Impurity levels were assessed using thresholds from the United States and European Pharmacopoeias monographs.

Findings: A convenient samples of 4951 antidiabetic drugs were collected from 13 sub-Saharan African countries (Seven middle-income and six low-income countries). Out of the 1673 (of 4951 collected) drug samples randomly tested, 28·0% (n: 468, 95% CI [22·3-33·0]) failed to meet standards related to the expected content of active ingredients (B: 27·2% 95% CI [21·5-32·0]; C: 0·8% 95% CI [0·2-3·5]), with more samples showing underdosage (19·31% 95% CI [14·8-24·3]) than overdosage (8·67% 95% CI [5·3-12·5]). Impurity levels were excessive in 9·68% (n: 162, 95% CI [6·0-14·8]) of samples. Overall, 32·8% (n: 548, 95% CI [26·5-38·1]) were deemed to be of poor quality according to active ingredient content or impurity level. In multivariate logistic regression, factors associated with worse quality were drugs, expired status, and country of purchase.

Interpretation: In this multinational study assessing the quality of antidiabetic drugs in sub-Saharan Africa, we found a significant proportion of poor-quality drugs. National health authorities must take action to ensure access to safe, high-quality medications for diabetic patients.

Funding: DIABDAF study was exclusively supported by French public grant (INSERM, AVIESAN, AP-HP, and University of Paris Cité).

Keywords: Africa; Antidiabetic agents; Counterfeit drugs; Diabetes; Drug quality; Drugs; Falsified drugs; Insulin; Low- and middle-income countries; Substandard.

Fig. 1

Collected samples of antidiabetic drugs by countries, level-income countries and version of drugs n = 4951.

Fig. 2

Poor quality of antidiabetic drug according to level of impurity (left) or content of active ingredient (right) per group characteristics. Legend: ∗Differences in drug level of impurity and in content of active ingredient per group characteristics were assessed by univariate logistic regression, with a random effect on batch (a batch gathers samples issued from one drug, in one pharmaceutical presentation collected in one country, and in one place of sale).

Fig. 3

Proportions of antidiabetic drugs poor quality as defined by the dosage of active ingredient and level of impurity across the 13 countries of DIABDAF Study∗. Legend: ∗In each country, these proportions derived from convenient samples in licensed and unlicensed places of sales, in mostly capital and border cities. DIABDAF: quality assessment of antiDIABetic Drugs in AFrica.