AbstractObjectiveTo assess the sustainability, robustness and economic advantages of high‐performance thin layer chromatography (HPTLC) for quality control of pharmaceutical products.MethodWe compared three laboratories where three lots of cotrimoxazole tablets were assessed using different techniques for quantifying the active ingredient.ResultThe average assay relative standard deviation for the three lots was 1.2 with a range of 0.65–2.0.ConclusionHigh‐performance thin layer chromatography assessments are yielding valid results suitable for assessing product quality. The local pharmaceutical manufacturer had evolved the capacity to produce very high quality products.