Part I (Chapters 1-6) of this dissertation describes the use of stability-indicating HPLC methods for ephedrine sulfate, lidocaine hydrochloride, neostigmine methylsulfate, glycopyrrolate, succinylcholine chloride, and tubocurarine chloride stored individually in polypropylene syringes at ambient temperature (241C) or under refrigeration for either 60 or 90 days.|In Part II, HPLC is employed for the analysis of selected pharmaceuticals in dosage forms and human plasma studies.|Chapter 7 reports an assay for the simultaneous determination of guaifenesin-pseudoephedrine- dextromethorphan and guaifenesin-pseudoephedrine in commercially available capsule dosage forms and guaifenesin-codeine in a commercial cough syrup dosage form. For each drug mixture, the separation was achieved within 10 minutes. The method showed linearity for the guaifenesin-pseudoehedrine-dextromethorphan mixture in the 50-200, 7.5-30, and 2.5-10 mg/ml ranges, respectively. The guaifenesin-pseudoephedrine mixture yielded linear ranges of 25-100 and 3.75-15 mg/ml, respectively. The method showed linearity for the guaifenesin-codeine mixture in the 25-100 and 2.5 to 10 mg/ml ranges, respectively. The intra- and inter-day precision and precision for the analytes in each mixture ranged from 0.13-5.04%.|Chapter 8 describes a stability-indicating HPLC assay for the separation and quantitation of epinephrine-prilocaine and epinephrine-procaine combinations in their respective dosage forms. The method showed linearity for the epinephrine-prilocaine mixture in the 0.25-2.5 and 8-200 mg/ml ranges, respectively. The intra- and inter-day RSDs ranged from 0.26 to 2.05% and 0.04 to 0.61% for epinephrine and prilocaine, respectively. The epinephrine and procaine mixture yielded linear ranges of 0.25-2.0 and 5-100 mg/ml ranges, respectively. The intra- and inter-day RSDs ranged from 0.3 to 1.88 and 0.07 to 0.26% for epinephrine and procaine, respectively. Stability-indicating HPLC assays were also developed for levonordefrin-tetracaine-procaine, levonordefrin-procaine- propoxycaine, and norepinephrine-procaine-propoxycaine drug combinations.|Chapter 9 describes an HPLC method for the determination of amoxicillin, metronidazole, and pantoprazole in human plasma. Solid-phase extraction was employed to extract the analytes along with the internal standard (tinidazole). Limits of detection were 200 ng/ml for amoxicillin and metronidazole and 100 ng/ml for pantoprazole. Recoveries from human plasma ranged from 83-92% for amoxicillin, 81-89% for metronidazole, 85-94% for tinidazole, and 93-101% for pantoprazole. Intra-day (n=5) and inter-day (n=15) precision (%RSD) and accuracy (%error) for analytes ranged from 1.11-5.97% and 0.72-13.5%, respectively.