Determination of Didanosine in Human Plasma by Electro Spray Ionization LC-MS/MS Method

Abstract

A rapid and sensitive analytical method based on high-performance liquid chromatographytandem mass spectrometry (LC-MS/MS) has been developed for the determination of didanosine in human plasma. Sample preparation involved solid phase extraction technique. Chromatography was carried out on an Inertisil ODS 3V column using a mixture of 10 mM ammonium acetate (pH 6.5 ± 0.1) and acetonitrile in a ratio of 10:90 v/v as the mobile phase at a flow rate of 0.6 mL/min. Detection by electro-spray negative ionization mass spectrometry and multiplereaction monitoring of the transitions of didanosine at m/z 235.2 → 135.2 and of zidovudine at m/z 266.3 → 223.1 was linear over the concentration range 20 (LLOQ)-4000 (ULOQ) ng/mL. Intra-day and inter-day precisions (CV %) were ≤ 5.7 and ≤ 10.2 %, respectively. Accuracy (in terms of percentage relative error) was with in the range of -4.85 to 6.16. Recovery and matrix effect were examined and found to be within acceptable limit (percentage coefficient variance ≤ 15). The method was validated as per FDA and ICH guidelines.