Assessing the quality of anti-malarial drugs from Gabonese pharmacies using the MiniLab®: a field study

BackgroundRecent studies alluded to the alarming scale of poor anti-malarial drug quality in malaria-endemic countries, but also illustrated the major geographical gaps in data on anti-malarial drug quality from endemic countries. Data are particularly scarce from Central Africa, although it carries the highest burden of malaria. The aim of this medicine quality field survey was to determine the prevalence of poor-quality anti-malarial drugs in Gabon.MethodsA field survey of the quality of anti-malarial drugs in Gabonese pharmacies was conducted using the Global Pharma Health Fund Minilab® tests, following the Medicine Quality Assessment Reporting Guidelines. Anti-malarial drugs were purchased randomly from selected pharmacies in Gabon. Semi-quantitative thin-layer chromatography (TLC) and disintegration testing were carried out to measure the concentration of active pharmaceutical ingredients (APIs). The samples failing the TLC test were analysed by high-performance liquid chromatography. Following the collection of anti-malarial drugs, a street survey was conducted to understand where people purchase their anti-malarial drugs.ResultsA total of 432 samples were purchased from 41 pharmacies in 11 cities/towns in Gabon. The prevalence of poor-quality anti-malarial drugs was 0.5% (95% CI 0.08–1.84%). Two out of 432 samples failed the MiniLab® semi-quantitative TLC test, of which a suspected artemether-lumefantrine (AL) sample was classified as falsified and one sulfadoxine-pyrimethamine (SP) sample as substandard. High performance liquid chromatography with ultraviolet photo diode array detection analysis confirmed the absence of APIs in the AL sample, and showed that the SP sample did contain the stated APIs but the amount was half the stated dose. Of the people interviewed, 92% (187/203) purchased their anti-malarial drugs at a pharmacy.ConclusionUsing the GPHF Minilab®, the prevalence of poor-quality anti-malarial drugs is far lower than anticipated. The findings emphasize the need for randomized and robust sampling methods in order to collect representative data on anti-malarial drug quality.Trial registration: NTR4341 (Dutch Trial Registry)ResumeContexteDes études récentes ont fait allusion à l'ampleur alarmante sur la qualité des médicaments antipaludiques dans les pays d'endémie. Elles ont aussi illustré les principales lacunes des données géographiques concernant les médicaments antipaludiques dans les pays endémiques. Les données sont particulièrement rares en Afrique centrale, bien que cette région porte le plus lourd fardeau du paludisme. Le but de cette enquête sur le terrain était de déterminer la prévalence des médicaments antipaludiques de mauvaise qualité au Gabon.MéthodesUne enquête sur le terrain a été réalisée sur la qualité des médicaments antipaludiques dans les pharmacies gabonaises en utilisant les tests ‘Global Pharma Health Fund Minilab®’, suivant la ‘Medicine Quality Assessment Reporting Guidelines (MEDQUARG)’. Les médicaments antipaludiques ont été achetés dans des pharmacies choisies au hasard au Gabon. La chromatographie semi-quantitative en couche mince (CCM) et le test de désintégration ont été effectués pour mesurer la concentration d'ingrédients pharmaceutiques actifs (API). Les échantillons qui n’ont pas réussi le test CCM ont été analysés par chromatographie en phase liquide à haute performance. Après la collecte des médicaments antipaludiques, une enquête communitaire a été menée pour comprendre où les gens achètent leurs médicaments.RésultatsUn total de 432 échantillons ont été achetés dans 41 pharmacies de 11 villes au Gabon. La prévalence de médicaments antipaludiques de mauvaise qualité était de 0,5% (IC 95% de 0,08 à 1,84%). Sur les 432 échantillons, le test semi-quantitatif de chromatographie sur couche mince Minilab® n’a permis de détecter aucune substance active sur deux échantillons, dont un échantillon d’artéméther-luméfantrine (AL) suspecté contrefait et un échantillon de sulfadoxine-pyriméthamine (SP) ont été classées échantillon de qualité inférieure. L’analyse pour la détection d’APIs dans l’échantillon AL par chromatographie liquide à haute performance avec photo ultraviolet de réseau de diodes a confirmé l'absence d'API et a montré que l'échantillon de SP contient les énoncés API mais la quantité était la moitié de la dose indiquée. Parmi les personnes interrogées, 92% (187/203) ont acheté leurs médicaments dans une pharmacie.ConclusionL'utilisation du GPHF Minilab®, la prévalence des médicaments antipaludiques de mauvaise qualité est grandement inférieur à celle prévue. Les résultats soulignent la nécessité pour les méthodes d'échantillonnage aléatoire et robustes afin de recueillir des données représentatives sur la qualité des médicaments antipaludiques.

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