A novel, specific, simple, precise, accurate, stability-indicating RP-HPLC methods and different spectrophotometric methods as First derivative ratio, ratio difference and ratio subtracting methods are developed and validated for the determination of some pharmaceutical drugs produced by Hikma Company which are used in the treatment of seasonal and perennial allergic conjunctivitis, chronic hepatitis C (CHC) in adults and antibacterial. These drugs include Azelastine hydrochloride (AZH), Benzalkonium chloride (BAC), Sofosbuvir (SOF), Ledipasvir (LDV), Cefixime trihydrate (CFX) and Sodium benzoate (SDM) in pure and in pharmaceutical dosage forms. Surveying the literature dealing with the same technique with drugs similar to that under study, Checking the validity of the applied analytical method and achieving the optimum condition according to ICH. Study of the stability indicating method using stress condition to validate the method of analysis of the drugs under study. Finally, the obtained results for the proposed methods were statistically compared with the official methods using student's and F-ratio tests, showing that the two methods are accurate and precise. Skryť popis