The present thesis is devoted to develop some analytical methods for determination of some drugs that used for treatment the complications of diabetic and rheumatic diseases This thesis comprises five parts describing the introduction and literature review, the experimental work, the references and Arabic summery. Part I: Introduction and literature review Part II: Spectroscopic methods. This part divided into four sections, section A: flourimetric study on antidiabetic combined drugs; empagliflozin and linagliptin in their pharmaceutical formulation and human plasma, section B: different spectrophotometric method for determination of empagliflozin and linagliptin in their pharmaceutical formulation , section C: stability indicating spectrophotometric methods for determination of bumadizone Calcium hemihydrate in the presence of its degradation, section D: stability indicating chemometric methods for determination of bumadizone Calcium hemihydrate in the presence of its degradation including PLS and PCR chemometric methods. Part III: Miceller UPLC method for determination of four hypoglycemic agents in their pharmaceutical dosage form and human plasma. Part IV: Eco-friendly cyclic and differential pulse voltametric determination of bumadizone Calcium hemihydrate in pure, pharmaceutical dosage form and in spiked human plasma using pencil graphite sensor. Part V: General conclusion.