الفهرس 
Part ?: General IntroductionOnly 14 pages are availabe for public view
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Abstract
The present thesis is devoted for the development and validation of spectroscopic and chromatographic methods which are cost effective and environmentally safe for determination of five CNS drugs including; Quetiapine, pramipexole, citicoline, piracetam, and paroxetine. The developed methods include spectrofluorimetric, spectrophotometric coupled with chemmometric, TLC-densitometric, and HPLC methods.
The thesis is composed of three main parts:
Part Ⅰ: general introduction
This part provides an overview of the studied drugs, their pharmacological actions and chemical structures. It also includes literature review for analytical techniques that were previously reported for determination of studied drugs in pure forms, pharmaceutical formulations and/or biological fluids. At the end of this part, the objective of the suggested work was discussed.
Part ⅠⅠ: spectroscopic technique
This part consisted of four chapters;
Chapter (A): Innovative Spectrofluorimetric Protocol Based on Micro-Environment Improvement for Determination of Quetiapine in Dosage forms and Rat Plasma
This chapter describes the development of a simple, rapid, and highly sensitive micellar spectrofluorimetric method for quantitation of QUT in its pharmaceutical formulations. The proposed method was based on the enhancement of the fluorescence intensity of QUT in 2% v/v tween 80 micellar solution. The fluorescence intensity was measured at 372 nm after excitation at 261 nm. A linear relationship was achieved between the fluorescence intensity and the drug concentration in the range of 20-1000 ng/mL with 18 and 6 ng/mL as limits of quantitation and detection, respectively. The simplicity of the method allows its application of the uniformity of tablet dosage forms. The proposed method was extended to study the stability of QUT after its exposure to different forced degradation conditions such as; acidic, alkaline, oxidative, photolytic and thermal conditions according to ICH guidelines. The study revealed that QUT is stable under all the of these conditions except the oxidative one. Furthermore, the high sensitivity of the micellar method permits its application for determination of QUT in rat plasma.
Chapter (B): Highly Sensitive Spectrofluorimetric Method for Quantitation of Pramipexole Via Derivatization with Fluorescamine; Application to Content Uniformity Testing
The present chapter illustrates the development and validation of a sensitive and selective spectrofluorimetric method for quantitation of pramipexole (PMP) through its interaction with fluorescamine at pH 7.5 using aqueous borate buffer. The fluorescent intensity of the formed highly fluorescent product was measured at 480 nm after excitation at 391 nm. The experimental factors that could influence the formation, stability or the fluorescence intensity of the formed product were investigated and adjusted. Linearity of the method for PMP determination was achieved in the concentration range of 0.05 – 2.0 μg/mL. The limits of quantitation and detection were 47 and 15 ng/mL, respectively. The proposed method has been validated in respect to guidelines of ICH and pharmaceutical tablets of PMP were successfully analyzed. Moreover, the method was applied for studying the content uniformity test according to the guidelines of United States Pharmacopeia.
Chapter (C): Spectrofluorimetric Approach for Determination of Citicoline in the Presence of Co-formulated Piracetam Through Fluorescence Quenching of Eosin Y
This chapter introduces a simple, sensitive, and precise spectrofluorimetric method for quantitation of citicoline in its pharmaceutical formulations. The proposed method was based on quantitative quenching effect of citicoline on the native fluorescence of eosin Y via developing of a binary complex reaction between the cited drug and eosin Y in acidic medium using acetate buffer pH=3.6. The quenching of the fluorescence of eosin was measured at 540 nm after excitation at 518 nm. Calibration graph was achieved in the range of 300-3000 ng/mL with 0.9996 as correlation coefficient. The quantitation and detection limits were 291.0 and 93.86 ng/mL, respectively. The developed method is considered as the first spectrofluorimetric one for quantitation of citicoline. The method was validated according to ICH guidelines. The selectivity of the proposed method was investigated by studying the interference of piracetam as co-formulated drug. The developed method could be used for routine quality control of citicoline in its pharmaceutical formulations either alone or in combination with piracetam.
Chapter (D) Stability Indicating Multivariate Calibration Methods for Simultaneous Determination of Citicoline and Piracetam.
In this chapter, citicoline and piracetam were subjected separately to different stress conditions including acidic, alkaline, oxidative, photolytic and thermal conditions as recommended by the international conference on harmonization (ICH). characterization of the degradation products was carried out by IR, and MS analyses. UV-spectrophotometry coupled with two multivariate calibration models, namely; partial least squares (PLS) and principal component regression (PCR) were constructed for the determination of CIT, PIR, and their degradation products (CD, CH and PD). Multilevel multifactor design was used for construction of the calibration and validation sets. A five-level, five-factors calibration design was used to prepare 25 mixtures with different ratios in the concentration ranges of 3-12, 3-12, 2-6, 2-6, and 5-25 μg/mL for CIT, PIR, CD, CH and PD, respectively. The absorption spectra of the prepared mixtures were recorded in the range of 200 - 400 nm and transferred to Matlab® 6.5 for subsequent data manipulation. Twenty-five mixtures were used for building the calibration model, while eight mixtures were randomly chosen and used as an external validation set. The two multivariate calibration models were successfully applied for the determination of the studied drugs and their degradation products in pharmaceutical products and samples exposed to different forced degradation conditions.
Part ⅠⅠⅠ: chromatographic technique
This part consisted of two chapters;
Chapter (A): Development of chromatographic Stability Indicating Methods for Determination of Citicoline and Piracetam Following ICH Recommendations
This chapter represents a new stability indicating TLC-Densitometric and UPLC methods for simultaneous determination of citicoline and piracetam in presence of their degradation products. Separation on the proposed TLC-densitometric method was carried out using a developing system containing methanol: chloroform: ammonium buffer (pH=11.5) (9:1:2, by volume) on TLC silica gel 60 F254 plates followed by densitometric scanning at 230 nm. On the other hand, the mobile phase in the UPLC method was composed of water (containing 0.1% triethylamine, pH=8.5): ethanol (92:8, v/v) and the stationary phase was C8 column. The flow rate was 1 mL/min and UV detection was at 230 nm. The developed methods were validated according to ICH guidelines and demonstrated good accuracy and precision. Moreover, results of the developed TLC-densitometric and UPLC methods were statistically compared to those obtained by the reported RP-HPLC method using t- and F- tests and no significant difference between them was found. The proposed chromatographic methods are considered the first stability indicating assay for the simultaneous determination of CIT and PIR in presence of their degradation products. The developed UPLC method is faster than the reported HPLC ones and utilizes solvents with less environmental hazards. Eco scale score and greenness profile of UPLC method were assessed and compared with those of the previously published HPLC methods. It was noticed that the proposed UPLC method is more environmentally friendly and greener than other reported methods.
Chapter (B): Green chromatographic methods for simultaneous determination of quetiapine and the co-administrated paroxetine in rat plasma with application to pharmacokinetic study
This chapter describes a newly established green TLC-densitometric and RP-HPLC methods for simultaneous determination of quetiapine (QUT) (an antipsychotic drug) and the co-administrated drug, paroxetine (PAR) (an antidepressant drug). Both drugs are widely prescribed for treatment of bipolar depression. The proposed TLC-densitometric method was based on separation of the studied components and the internal standard (vincamine (VINC)) using a developed system of ethyl acetate: ethanol: ammonia solution 33% (8: 2:0.05, by volume) on TLC silica gel 60 F254 plates and scanning at 240 nm. Linear relationships were obtained over a concentration range of 150-3000 ng/band for both using 1000 ng/mL of the internal standard. On the other hand, the proposed RP-HPLC method depended on separation of the studied components and the internal standard using a mixture of methanol: 0.05 M KH2PO4 (pH 4.3) (70:30, v/v) on XTerra® HPLC RP C18 column (4.6 mm × 250 mm, 5 µm) at a flow rate of 1 mL/min, and UV detection at 240 nm. Linearity was achieved on the concentration range of 150-5000 ng/mL for both using 1000 ng/mL of the internal standard. The greenness profile of the developed methods was assessed and compared with reported HPLC method using the analytical Eco-Scale as an assessment tool. The proposed methods were found to be greener than the reported method. Furthermore, the developed methods were validated following FDA guidelines and all parameters met the acceptance criteria. In addition, both methods were successfully used to study the pharmacokinetic parameters of both QUT and PAR after their co-administration in rats and results showed that both drugs affected the pharmacokinetic parameters of each other when administrated together. The developed methods can be used for further monitoring of the studied drugs in patients.
In addition, the thesis includes 54 tables, 41 figures, and 342 references, English summary and an Arabic summary.