Monitoring the quality of quinine injection in retail outlets in south-east Nigeria

Purpose: To determine the pharmaceutical quality of quinine injections sold in retail outlets in SouthEast Nigeria.Methods: Eleven brands of 2 mL quinine injection (300 mg/mL) were examined for their quality and conformity to pharmacopeial standards. Various tests such as sterility, pH, clarity, extractable volume, test for identification and content uniformity test were performed as quality control measures. Content assay was determined by non-aqueous titration and UV spectrophotometry following the methods described in the British and United States Pharmacopoeias.Results: All brands were sterile, without leakages and contained no particulate matter on white and black backgrounds. The extractable volumes from all the brands were slightly higher than expected, 2 mL. pH analysis showed that the injections have a pH not higher than 4.0. Only the brand, coded QH06, was outside the standard acceptable content of 90 – 110 % in both assay techniques. The non-aqueoustitrimetric technique showed that only samples coded QH02, QH03, QH04 and QH08 contained 90 – 110 % of quinine, representing 36.4 %, while 72.7 % of the samples contained quinine within 90 – 110 % using UV spectrophotometric assay.Conclusion: The study showed the presence of substandard quinine injection in Southeast Nigeria, which was characterized by suboptimal quinine strength. There is a need for regular post-marketing surveillance of available antimalarial injections in Nigeria to achieve therapeutic outcomes.