Design of Simple UV Spectrophotometric and HPLC Methods for the Assay of Artemether and Lumefantrine in Fixed-Dose Combination Tablets

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Artemether-Lumefantrine combinations have become very important in the treatment of uncomplicated malaria. However, there are very few methods to assay these fixed-dose combination formulations. To help in ensuring the quality of these medications, simple and sensitive Ultra-Violet (UV) Spectrophotometric and High Performance Liquid Chromatographic (HPLC) methods of assaying Artemether and Lumefantrine in fixed-dose combination tablets were developed and validated. The UV Spectrophotometric method for the assay of Lumefantrine made use of a 0.1M methanolic HCl solution of Lumefantrine, with the analysis being carried out at 335nm whilst the UV assay of Artemether made use of its HCl decomposition product, with the analysis being carried out at 254nm. In the fixed-dose combination tablets, the UV methods proved suitable for the assay of only Lumefantrine, as Lumefantrine interfered with the analysis of Artemether. The assay of Artemether by the UV Spectrophotometric method was however possible in Artemether-only tablet formulations. The HPLC method required the separate analysis of Artemether and Lumefantrine as a simultaneous analysis of the two was not possible. The assay of Lumefantrine employed a C18 reverse phase column (Ultracarb 3μ ODS (20)) with an isocratic mixture of methanol and 0.1% Trifluoroacetic acid in water (90:10) as the mobile phase. The flow rate was 2.5ml/min and detection was by means of a UV detector set to 335nm. The retention time of Lumefantrine was 6.0 ± 0.19 minutes. The assay of Artemether employed the same C18 reverse phase column with an isocratic mixture of methanol and 0.04% Trifluoroacetic acid (90:10) as the mobile phase, pumped at a rate of 2.5ml/min. Detection was carried out with a UV detector set to 235nm. The retention time of Artemether was 5.8 ± 0.15 minutes. Six brands of Artemether-Lumefantrine fixed-dose combination tablets on the Ghanaian market (one local and five foreign) were analyzed. All the brands passed the Uniformity of Weight Test and the Tablet Disintegration Test. Of the Six brands of Artemether-Lumefantrine fixed-dose combination tablets analyzed, all passed with respect to their Lumefantrine content using both UV and HPLC. Two of the foreign brands however failed with respect to their Artemether content.
A Thesis Submitted In Partial Fulfilment Of The Requirements For The Degree Of Master Of Science In Pharmaceutical Analysis And Quality Control in the Department of Pharmaceutical Chemistry.