In this work analytical methods were developed for determination of some drugs used in elderly diseases and in treatment of skeletal muscle disorders. The objective of the present work is to develop smart, simple, accurate and economic methods for determination of such drugs, in pure forms as well as in their pharmaceutical dosage forms or biological fluids. The thesis falls in five parts: Part I: Introduction and literature review. Part II: Spectroscopic methods: This part divided into four chapters. Chapter 1: Enhanced green spectrofluorimetric method for quantitative analysis of a prucalopride succinate in its pharmaceutical dosage form and biological fluids: Application of molecular dynamic simulation technique. Chapter 2: Earth friendly spectrophotometric methods based on different manipulation approaches for simultaneous determination of aspirin and omeprazole in binary mixtures and pharmaceutical dosage form: Chapter3: Spectrophotometric determination of aspirin and omeprazole in the presence of salicylic acid as a degradation product: A comparative evaluation of different univariate/multivariate post processing algorithms Chapter 4: Spectrophotometric methods for determination of brinzolamide and brimonidine tartrate in their pure form and pharmaceutical formulation. Part III: Chromatographic methods: This part divided into two chapters. Chapter 1: Development and validation of eco-friendly micellar-UPLC method for determination of brinzolamide, timolol maleate, travoprost and brimonidine tartrate in bulk powders and pharmaceutical dosage forms. Chapter 2: Development and validation of RP-HPLC method for determinations of benazepril hydrochloride, quetiapine fumarate and amlodipine besylate in human plasma and pharmaceuticals. Part IV: Eco-friendly electrochemical analysis of prucalopride succinate in pharmaceutical formulation using disposable pencil graphite electrode Part V: General conclusion.