Obi P. Adigwe’s scientific contributions

Medicine security remains one of the public health challenges in Sub-Saharan Africa as the report by World Health Organization (WHO) shows that 10.5% of medicines in low and middle-income countries worldwide are falsified or substandard. The study aimed to evaluate the quality of Oral Rehydration Salt (ORS) products sold in pharmacy outlets in Abuja, Nigeria. Seventeen different commercial brands of WHO recommended low-osmolarity ORS finished pharmaceutical products (FPP) were randomly selected from pharmacy outlets in the Federal Capital Territory (FCT) and Gwagwalada Area Council in Abuja. They were assessed for quality based on physicochemical properties and the content of active pharmaceutical ingredients in accordance with the International Pharmacopeia (IP) guidelines. The shelf lives of all the samples were valid, and they all met the visual inspection test, labelling, pH (7.4‒8.0 between23.3‒23.9°C) and moisture content (1‒9 mg/g) requirements. The content assay revealed 88.2%, 88.2%, 64.7%, 47.1%, and 35.3% compliance of the samples for glucose, chloride, citrate, sodium and potassium, respectively. Twelve (76.5%) of the brands failed at least one content assay and 8 (47%) had zero potassium content. The study underscores the need for regular, periodic post-market surveillance on essential medicines sold in the Nigerian market.

Tea is commonly consumed in Nigeria. Caffeine, a major constituent in tea, has some beneficial pharmacological properties, but can negatively affect human health if consumed excessively. The objective of the study was to evaluate some physicochemical properties and caffeine content of teas marketed in FCT, Abuja, Nigeria. Ten commercial brands of teas (8 black teas and 2 green teas) were assessed for weight variation, moisture content and pH tests using standard methods. Extraction of caffeine was carried out and the identity determined by thin layer chromatography and melting points, respectively. High performance liquid chromatography (HPLC) method for analysis of caffeine was developed, validated, and applied to determine caffeine content in the tea brands. Results of the weight, moisture content and pH tests of the samples ranged from 2.07–2.33 g, 5.65–11.0 % and 4.9–5.5, respectively. Caffeine was isolated from all the samples and showed same Rf value (0.46) with that of the reference standard. Melting points ranged from 236.0–238.5 °C. Caffeine content ranged from 12.25–21.76 mg/g for black teas and 13.35–15.05 mg/g for green teas. The study provides information on the stability, acidity and caffeine content in some commercially available tea brands.