pH and Titratable Acidity of different Cough Syrups in Nigeria

Abstract

Background: Cough linctuses are liquid oral medicines widely used in children to treat cough and related conditions. Some of their constituents are acidic and dental erosive. Objectives:  This in vitro study aimed to evaluate the endogenous pH and titratable acidity of Nigerian cough syrups and also determine their erosive potentials.  Methods: Twenty-five commonly used cough syrups were evaluated. The pH of each cough syrup was determined using a digital pH meter. Also, the buffering capability of each cough syrup was assessed by titrating 0.1N Sodium hydroxide (NaOH) with 10mls of each sample until neutral pH of 7.0 was achieved for acidic syrups. For alkaline samples, 0.1N Hydrochloric acid (HCl) was titrated until the neutral pH of 7.0 was achieved. Results: The pH of the syrups ranged from 3.06 to 8.4. Twenty three (92%) of them were acidic (pH<7) while fifteen (60%) showed pH below the critical value of 5.5 which is a pH condition for enamel dissolution. Compared with the control (Coca-cola), all the samples showed comparable but slightly higher pH levels. The titratable acid values were between 0.1 and 4.1 mls. Eleven samples required at least 1.7mls of 0.1N sodium hydroxide to be neutralized. Only Deshalom – Cof needed more NaOH (4.1mls) to be neutralized compared with the control (3.1mls). Conclusion: Sixty percent of the sampled syrups were acidic with pH values below 5.5.