Simple and reliable analytical techniques for drug analysis in pharmaceutical and bio-fluids forms /

Abstract

In the field of pharmaceutical analysis, a recent challenge involves quantifying and resolving drugs within a variety of matrices. These matrices contain different endogenous compounds that can interfere with drug analysis. The compounds investigated throughout this work were determined in pharmaceutical dosage form, human plasma, and urine. These compounds include amlodipine, olmesartan, and molnupiravir. The thesis consists of five parts. Part I: General Introduction and Literature Review This part provides an overview of common analytical and extraction techniques used for separating mixtures, and a brief on the experimental design. Also it discusses pharmacological effect of selected compounds, their structures and solubility in different solvents and literature review about techniques for detection of drugs in pharmaceutical dosage and bio-fluids forms. Part II: Chromatographic determination of Amlodipine and Olmesartan in pharmaceutical dosage form and human plasma using HPLC. This part is subdivided into four sections: Section A: Chromatographic determination of Amlodipine and Olmesartan in pharmaceutical dosage form using HPLC coupled with UV-detector. In this section, High-Performance Liquid Chromatography (HPLC) technique using UV detector has been developed for the determination of amlodipine and olmesartan in pharmaceutical dosage forms. The method focused on obtaining the optimal conditions for separating these drugs effectively. Separation was achieved by using a mobile phase consisting of acetonitrile and 0.01M potassium dihydrogen phosphate ratio (40:60, v/v) at pH 2.5. Elution was performed isocratically at a wavelength of 254.0 nm, with a flow rate of 1.0 mL/min. This proposed method was successfully applied to pharmaceutical dosage forms available in the local market. Section B: Chromatographic determination of Amlodipine and Olmesartan in human plasma using HPLC coupled with UV-detector. In this section, HPLC technique using UV detector has been developed for the determination of amlodipine and olmesartan in human plasma. The method focused on using the optimal conditions for separating these drugs effectively without interference from the plasma endogenous compounds. Separation was achieved by using a mobile phase consisting of acetonitrile and 0.01M potassium dihydrogen phosphate (32:68, v/v) at pH 2.5. Elution was performed isocratically at a wavelength of 254.0 nm, with a flow rate of 1.0 mL/min. Section C: Chromatographic determination of Amlodipine in pharmaceutical dosage form using HPLC coupled with Fluorescence-detector. In this study, an HPLC method with Fluorescence detection includes the determination of amlodipine in its drug formulation. The separation was carried out at using mobile phase composed of acetonitrile and potassium dihydrogen phosphate buffer (pH 2) in ratio (40:60, v/v%), The isocratic elution performed at emission adjusted at 439 nm and the excitation at 254 nm and the flow rate was 1.0 mL/min. Section D: Chromatographic determination of Amlodipine in human plasma using HPLC coupled with Fluorescence-detector. In this section, an HPLC method using fluorescence detector, enables the determination of amlodipine with good accuracy and precision to allow its detection in human plasma. The developed method was based on obtaining optimum conditions to separate the drug and avoid the interference of the plasma endogenous compounds. The separation was carried out with mobile phase of acetonitrile and 0.01M dihydrogen phosphate (pH 2.5) in ratio (32:68, v/v%). The flow rate was adjusted to 1.0 mL/min at emission wavelength of 439.0 nm and excitation wavelength at 254.0 nm. Part III: Spectroscopic methods for the determination of Amlodipine and Olmesartan with the aid of chemometrics This part is subdivided into three sections: Section A: Introduction to chemometrics This section includes an introduction about most common multivariate data analysis techniques used to identify drugs in binary mixtures. Also it demonstrates the process of multivariate calibration, data preprocessing, and model validation. Section B: Spectrophotometric method for the determination of Amlodipine and Olmesartan with the aid Of Chemometrics In this section, a spectrophotometric method for analysis of binary mixtures containing amlodipine and olmesartan was demonstrated. At first principal component regression (PCR) was used for obtaining the outer layers and scores. Partial least squares (PLS) was applied as multivariant method a calibration sets were prepared of different ratios of the binary mixtures. A leave one out cross-validation procedure was employed to find out the optimum numbers of latent variables at wavelength of 200.0-400.0 nm. This proposed method was successfully applied to pharmaceutical dosage form. Section C: Spectrofluorimetric method for the determination of Amlodipine and Olmesartan with the aid of Chemometrics In this study, a spectrofluorimetric method was applied for the determination of the binary mixture amlodipine and olmesartan. To obtain maximum intensity for both drugs the calibration sets were prepared in different ratios of the mixture in 50:50 methanol and distilled water with the addition of 1.0% sodium lauryl sulfate (SLS) surfactant and measured at excitation wavelength of 254.0 and emission wavelength of 439.0 nm. Principle component regression (PCR) was used for detecting the outer layers while Partial least squares (PLS), was applied as multivariant method. This proposed method was successfully applied to pharmaceutical formulations. Part IV: A Green Voltammetric Determination of Molnupiravir Using a Disposable Screen-Printed Reduced Graphene Oxide Electrode: Application for Pharmaceutical Dosage and Biological Fluid Forms In this part the proposed analytical platform involves the use of a disposable laboratory made screen-printed reduced graphene oxide 2.5.0% modified electrode (rGO-SPCE 2.5%) for the first time to measure MOV with high specificity. The surface morphology of the sensor was investigated by using a scanning electron microscope armed with an energy-dispersive X ray probe. The fabricated sensor attained reached high sensitivity when sodium dodecyl sulfate (SDS) surfactant (3 µM) was added to the supporting electrolyte solution of 0.04 M Britton– Robinson buffer at pH 2.0. The electrochemical activity of rGO-SPCE was examined in comparison with two different working electrodes in order to demonstrate that it was the most competitive sensor for MOV monitoring. This proposed method was successfully applied to pharmaceutical formulations.