Nitrogen and oxygen are constituents of molecules in every major drug class in pharmacology and medicine. Nitrogen and oxygen containing compounds include all of the major classes of pharmaceutically important drugs such as antiepileptics, antihypertensives, antivirals and vitamins. This work is devoted to the developmet of validated analytical methods for the determination of some compounds containing nitrogen and oxygen including pregabalin, oseltamivir, metoprolol, felodipine, metoclopramide and pyridoxine. The usefulness of different spectrophotometric, spectrofluorimetric and chromatographic methods was exploited. The proposed methods are of great value in quality control analysis of the studied compounds owing to their improved simplicity, sensitivity, low-cost, and its independence on expensive instruments, or critical analytical reagents.