title: Development and validation of a normal-phase high-performance thin layer chromatographic method for the analysis of sulfamethoxazole and trimethoprim in co-trimoxazole tablets.
abstract: Pneumocystis carinii pneumonia (PCP) is often the ultimate mortal cause for immunocompromised individuals, such as HIV/AIDS patients. Currently, the most effective medicine for treatment and prophylaxis is co-trimoxazole, a synergistic combination of sulfamethoxazole (SMX) and trimethoprim (TMP). In order to ensure a continued availability of high quality co-trimoxazole tablets within resource-limited countries, Medicines Regulatory Authorities must perform quality control of these products. However, most pharmacopoeial methods are based on high-performance liquid chromatographic (HPLC) methods. Because of the lack of equipment, the Tanzania Food and Drugs Authority (TFDA) laboratory decided to develop and validate an alternative method of analysis based on the TLC technique with densitometric detection, for the routine quality control of co-trimoxazole tablets. SMX and TMP were separated on glass-backed silica gel 60 F(254) plates in a high-performance thin layer chromatograph (HPTLC). The mobile phase was comprised of toluene, ethylacetate and methanol (50:28.5:21.5, v:v:v). Detection wavelength was 254 nm. The R(f) values were 0.30 and 0.61 for TMP and SMX, respectively. This method was validated for linearity, precision, trueness, specificity and robustness. Cochran's criterion test indicated homoscedasticity of variances for the calibration data. The F-tests for lack-of-fit indicated that straight lines were adequate to describe the relationship between spot areas and concentrations for each compound. The percentage relative standard deviations for repeatability and time-different precisions were 0.98 and 1.32, and 0.83 and 1.64 for SMX and TMP, respectively. Percentage recovery values were 99.00%+/-1.83 and 99.66%+/-1.21 for SMX and TMP, respectively. The method was found to be robust and was then successfully applied to analyze co-trimoxazole tablet samples.
authors.affiliation: Directorate of Laboratory Services, Tanzania Food and Drugs Authority, P.O. Box 77150, Dar es Salaam, Tanzania.
authors.forename: D H
authors.initials: DH
authors.lastname: Shewiyo
authors.forename: E
authors.initials: E
authors.lastname: Kaale
authors.forename: P G
authors.initials: PG
authors.lastname: Risha
authors.forename: B
authors.initials: B
authors.lastname: Dejaegher
authors.forename: J
authors.initials: J
authors.lastname: Smeyers-Verbeke
authors.forename: Y
authors.initials: Y
authors.lastname: Vander Heyden
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002855:Chromatography, Thin Layer / Q000379:methods*; D016014:Linear Models; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013420:Sulfamethoxazole / Q000032:analysis*; D013607:Tablets / Q000737:chemistry; D014295:Trimethoprim / Q000032:analysis*; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000737:chemistry*
chemical_list: D013607:Tablets; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D014295:Trimethoprim; D013420:Sulfamethoxazole