Development and validation of rapid UHPLC method for determination of aciclovir, its impurities and preservatives in topical cream
The aim of this study was to develop a new, rapid and sensitive method for simultaneous determination of aciclovir, three related substances and two preservatives methyl and propyl parahydroxybenzoates present in topical cream. This important active substance, aciclovir is the drug of the first choice for treatment of Herpes viral infections. Pharmacological mechanism is inhibition of replication of viral particles. Its major related substances are guanine, diguanine and diacetylaciclovir and they all were evaluated in this study. Preparation of the cream samples was very rapid and consisted of dissolution, sonication and filtration through membrane filter 0.22 μm. Innovative and expanding UHPLC method was chosen for proper analysis due to its excellent separation efficiency and resolution. Binary gradient flow was optimized to a C18 chromatographic column (100 mm × 3.5 mm, 1.7 μm). 0.1 M ammonium acetate buffer pH 5.5 and acetonitrile–water–tetrahydrofuran (90 : 6 : 4, v/v/v) were used as mobile phases in gradient mode with flow rate of 0.5 ml min−1. Separation temperature was increased to rarely used 60 °C. Wavelength of UV detector was set to 254 nm. This effective method was validated in accordance with ICH guidelines. Linearity, precision, accuracy, specificity, robustness, detection and quantitation limits were evaluated. The significance of the developed method is based on the analysis of important active substance aciclovir, its impurities and preservative in pharmaceutical preparation using UHPLC system with relatively high separation temperature which leads to radical analysis time shortening up to five times and solvent saving up to ten times comparing to the conventional HPLC system using 5 μm particle packed analytical column.