Quality of antiepileptic drugs in Vietnam

The purpose of this research was to evaluate the quality of anti-epileptic drugs (AEDs) in a central city of South Vietnam. A cross-sectional study was conducted in all the outlets for AEDs. Out of 33 pharmacies 54% had AEDs. Where the drugs were available, 89% of the pharmacies, 10 units were purchased, choosing the cheapest ones. The information on the packaging, the galenic form and the aspect of the drug were studied. Each sample's tablet was weighted and was considered satisfactory if it was within +/-10% of the average. A HPLC method was used for dosing the active ingredient (AI), which was considered satisfactory within +/-10% of the theoretical value. Eight samples were based on carbamazepin and eight on phenytoin. None of the 16 samples collected were past their expiring date. Tablets were homogeneous in shape, dimension and color. The uniformity of weight was satisfactory but the AI results were alarming for Carbamazepin and more often for Phenytoin. Only 35% of the tablets were correctly dosed. Because of differences of sensitivities of AEDs to storage conditions, environmental factors (heat, light and humidity) could be responsible for this result. Best results were achieved in structures where storage seemed to be better. The influence of storage conditions must be further studied to confirm this conclusion.