Evaluation of Brands of Ascorbic Acid Tablets on the Market After Exposure to Sunlight and Temperature in Sierra Leone

Abstract

This study evaluated the quality, stability, and regulatory status of selected vitamin C tablet brands marketed in Freetown under different storage conditions. An experimental study design was employed involving ten (10) brands of vitamin C tablets purchased from registered pharmacies in the Western Area Urban between October and November 2021. Baseline physicochemical analyses were conducted, after which samples were exposed to sunlight and elevated temperature (40 ± 1 °C) for six months, alongside a control stored under recommended conditions. Quality assessment was carried out in accordance with British Pharmacopoeia (BP) 2022 and USP <905> standards, including identification by Thin Layer Chromatography, assay of ascorbic acid content, uniformity of dosage units, friability, and disintegration testing. Results showed that friability values for all samples remained within acceptable limits (≤1%), indicating adequate mechanical strength. Significant degradation of ascorbic acid content was observed following exposure to sunlight and elevated temperature. At baseline, 7 out of 10 samples (70%) complied with BP assay specifications, while after six months of exposure, only 3 samples (30%)—C2, C5, and C7—remained within specification under both stress conditions. One sample (C9) consistently demonstrated extreme assay failure (≤58% of label claim) and failed the uniformity of dosage units’ test, with acceptance values ranging from 41.87 to 56.5. Additionally, 5 out of 10 products (50%) were unregistered, highlighting gaps in regulatory compliance within the pharmaceutical supply chain. Prolonged exposure to sunlight and high temperature reduces the chemical stability and dosage uniformity of vitamin C tablets, even when physical strength remains acceptable. The findings highlight the need for stronger regulatory oversight, enforcement of product registration, improved storage practices and increased public awareness to ensure the quality and safety of pharmaceutical products.