ABSTRACT
A mixture of acetaminophen, diphenhydramine hydrochloride and pseudoephedrine hydrochloride is used for the symptomatic treatment of common cold. In this study, a derivative spectrophotometric method based on zero-crossing technique was proposed for simultaneous determination of acetaminophen, diphenhydramine hydrochloride and pseudoephedrine hydrochloride. Determination of these drugs was performed using the [1]D value of acetaminophen at 281.5 nm, [2]D value of diphenhydramine hydrochloride at 226.0 nm and [4]D value of pseudoephedrine hydrochloride at 218.0 nm. The analysis method was linear over the range of 5-50, 0.25-4, and 0.5-5 microg/mL for acetaminophen, diphenhydramine hydrochloride and pseudoephedrine hydrochloride, respectively. The within-day and between-day CV and error values for all three compounds were within an acceptable range [CV<2.2% and error<3%]. The developed method was used for simultaneous determination of these drugs in pharmaceutical dosage forms and no interference from excipients was observed
Subject(s)
Spectrophotometry , Diphenhydramine/chemistry , Pseudoephedrine/chemistry , TabletsABSTRACT
A stability indicating High-Performance Liquid Chromatography [HPLC] method was validated and used to study the degradation of cetirizine dihydrochloride in acidic and oxidative conditions. The separation was carried out on a Symmetry C18 column and a mixture of 50 mM KH[2]PO[4] and acetonitrile [60:40 v/v, pH = 3.5] was used as the mobile phase. The method was linear over the range of 1-20 micro g/mL of cetirizine dihydrochloride [r[2] > 0.999] and the within-day and between-day precision values were less than 1.5%. The results showed that cetirizine dihydrochloride was unstable in 2 M HCl and 0.5% H[2]O[2]. The kinetics of the acidic degradation showed a pseudo-first-order reaction in the temperature range of 70-90[degree sign]C. In addition, the kinetics of hydrogen peroxide mediated degradation was pseudo-first-order in the temperature range of 50-80[degree sign]C