STUDY OF DIRECT AND INDIRECT ANALYTICAL METHODS FOR THE ANALYSIS OF SELECTED DRUGS OF PHARMACEUTICAL INTEREST CONTAINING BASIC AND/OR ACIDIC CENTER (S)

Abstract

This part presents a general introduction about the drugs used throughout the whole thesis covering the structure, chemical name, molecular weight, formula, physical properties, pharmacological action and uses of each drug. Additionally, detailed literature review describes the reported methods for analysis of the chosen drugs in bulk, in their pharmaceutical preparations or in biological fluids. Part II: In this part, a rapid green chromatographic method was developed for the simultaneous analysis of piroxicam (PIR), tolmetin (TOL), ketoprofen (KET), naproxen (NAP), aceclofenac (ACE), diclofenac sodium (DIC) and leflunomide (LEF). The method involved the application of HPLC with diode array detection where Zorbax Eclipse Plus-C18 column was used as stationary phase. Mixture of dibasic sodium phosphate (0.005 M, pH 5) and ethanol was used as a mobile system with gradient elution and flow rate 1 mL/min. Peak areas were measured at the wavelengths 275 nm. Peaks eluted in the following order: PIR eluted first at 3.6 min followed by TOL at 5.31min, KET at 6.55 min, NAP at 8.06 min, ACE at 10.39 min, DIC at 11.82 min, LEF at 13.70 min. In order to assess the stability-indicating power of the assay procedure, the drugs were subjected to forced degradation under stress conditions of hydrolysis (acidic, basic and neutral), oxidation and photolysis. The photo diode array detector was used as a tool for peak identification and purity confirmation. The method was found to distinctly separate the peaks of the parent drugs from their degradation products. The method was validated according to International Conference on Harmonization (ICH) Guidelines with respect to linearity, ranges, accuracy, precision, specificity, robustness and limits of detection and quantitation. Linearity ranges were 2 – 60 μg/mL for the seven drugs. The method was extended to both the in-vitro and in-vivo analysis of DIC and LEF in rat serum in presence if ACE as IS. The suggested method could be applied for the studied drugs in QC laboratories and pharmacokinetic studies.