 Corresponding author: Oluwadamilola M. Kolawole Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, University of Lagos, Lagos, Nigeria. Copyright © 2022 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0. Comparative qualitative and quantitative assessment of selected brands of Co- trimoxazole tablets and suspensions procured from Lagos State, Nigeria using first derivative UV spectroscopy and HPLC Oluwakemi Charles-Okhe, Oluwadamilola M Kolawole * and Boladale O Silva Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, University of Lagos, Lagos, Nigeria. World Journal of Biology Pharmacy and Health Sciences, 2022, 10(01), 103–114 Publication history: Received on 02 March 2022; revised on 14 April 2022; accepted on 16 April 2022 Article DOI: https://doi.org/10.30574/wjbphs.2022.10.1.0065 Abstract Background: The use of High-Performance Liquid Chromatography (HPLC) to evaluate the quality of co-trimoxazole formulations is relatively expensive, and First Derivative UV Spectroscopic (FDS) technique may be alternatively used. There are no studies evaluating the quality of locally manufactured sulphamethoxazole/trimethoprim (SMX/TMP) dosage forms procured from Lagos, Nigeria. The aim of the work was to evaluate the quality attributes of selected co- trimoxazole tablets and suspensions marketed in Lagos, Nigeria, and determine their API content using first derivative UV spectroscopy and HPLC. Methods: Ten samples each of Co-trimoxazole tablets and suspensions were procured and their quality attributes were evaluated using standard pharmacopeial methods while their drug content was quantified using FDS and HPLC methods. Results: 70 % of the tested tablet as well as all the suspension samples exhibited satisfactory quality attributes. In terms of the drug content assay, 60 % of the studied tablets and 40 % of the suspension brands were USP-compliant. The SMX and TMP content of the suspension formulations using FDS technique was generally less than that obtained using the HPLC method, suggesting that the active ingredients might have degraded. Conversely, there was good correlation in the drug content of the tablets using FDS and HPLC. Conclusion: First Derivative UV spectroscopy may be suitable to quantify the drug content of co-trimoxazole tablets while HPLC technique may be preferable for co-trimoxazole suspensions. Furthermore, stringent regulatory monitoring of the marketed co-trimoxazole products is required to assure the quality, safety and efficacy of marketed co- trimoxazole products, thereby safeguarding public health. Keywords: Sulphamethoxazole; Trimethoprim; First Derivative UV Spectrophotometry; HPLC; Qualitative and Quantitative Assessment