Usefulness of combined screening methods for rapid detection of falsified and/or substandard medicines in the absence of a confirmatory method.

Background: The influx of substandard and falsified medicines is a global public health challenge and its rapid detection is a key solution to the menace. This study used three screening methods and one confirmatory method for the quality assessment of 25 batches of artemether/lumefantrine dosage forms from the Ghanaian market to test that combined screening methods only can rapidly detect substandard and/or falsified medicines in areas where confirmatory methods may not be available.
Methods: The quality of artemether/lumefantrine tablet products obtained from pharmacies and licensed chemical seller shops within the Accra metropolis in Ghana were analysed using three screening methods (GPHF Minilab, Colorimetry and Counterfeit Drug Indicator) and one confirmatory method (high-performance liquid chromatography).
Results: The results showed that 18/25 batches of the artemether/lumefantrine samples passed using the combined screening and confirmatory methods and 5/25 batches of the artemether/lumefantrine samples failed using the combined screening and confirmatory methods. However, 1/25 batch of the artemether/lumefantrine samples failed using the combined screening methods but passed using the confirmatory method. Also, 1/25 batch of the artemether/lumefantrine samples passed using the combined screening methods but failed using the confirmatory method. This notwithstanding, the combined screening methods and the confirmatory method provided equivalent quality assessment profiles for 23/25 (92%) batches of the artemether/lumefantrine tablet products. Out of the 6 samples that failed the confirmatory test, 1/6, 2/6, and 3/6 failed on the high (> 110%), low (< 90%), and no active ingredient (0%), respectively. The sensitivity of Minilab, colorimetric, CoDI, and the combined screening methods at 95% confidence level were 0.5 ± 0.57, 0.83 ± 0.33, 0.75 ± 0.49, and 0.83 ± 0.33, respectively. Also, the specificity of Minilab, colorimetric, CoDI, and the combined screening methods at 95% confidence level were 1.00, 0.95 ± 0.10, 1.00, and 0.95 ± 0.10, respectively.
Conclusion: The combined screening methods may be used for rapid detection of falsified and/or substandard medicines without using a confirmatory method. However, additional research on the best combinations of screening devices/methods to rapidly detect the quality of medicines is recommended.