الفهرس 
General IntroductionOnly 14 pages are availabe for public view
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Abstract
This thesis focused on the detection and determination of some counterfeited drugs available in the market. The techniques used in this work were spectrophotometry and high performance liquid chromatography (HPLC). The thesis involves three parts Part I: General Introduction about Drug Counterfeiting This part involves an introduction about drug counterfeiting; definition of drug counterfeiting, types of drug counterfeiting, its risks to human health, examples of the dangers of counterfeit medications, detection of counterfeit drugs and its significance as well as the role of government to overcome this problem. Part II: Development and Validation of Analytical Methods for the Determination of Counterfeit Sildenafil This part consists of three chapters Chapter 1: Introduction about sildenafil and its counterfeits This chapter includes physical and chemical properties of sildenafil and its counterfeits (paracetamol, metronidazole and glyburide) as well as the reported methods for their analysis. : Development and Validation of New UV Spectrophotometric Methods for the Analysis of Counterfeit Sildenafil Citrate This chapter involves three methods. Method I was used for the determination of sildenafil and paracetamol by first derivative spectrophotometry at 311.8 nm and 265.8 nm for sildenafil and paracetamol, respectively. The linearity ranges were 10-42 μg/mL and 4-12.5 μg/mL for sildenafil and paracetamol, respectively. In method II, sildenafil was determined simultaneously with metronidazole by first derivative at 319.5 nm and 291.8 nm for sildenafil and metronidazole, respectively. The linearity ranges were 10-45 μg/mL and 4-16 μg/mL for sildenafil and metronidazole, respectively. In Method III, sildenafil was determined by direct UV spectrophotometry at 328 nm however glyburide was determined by ratio derivative spectrophotometry at 316.3 nm using 20 μg/mL sildenafil as a divisor. The linearity ranges were 20-100 μg/mL for sildenafil and 30-130 μg/mL for glyburide. Chapter 3: HPLC Methods for Detection of Counterfeit Dietary Supplements and Counterfeit Sildenafil This chapter involves two developed HPLC methods. Method I involved the development and validation of isocratic RP-HPLC method for the determination of sildenafil in counterfeit dietary supplements. The mobile phase used was 50 mM KH2PO4 (pH3.5): methanol (30:70, v/v), 0.3% tri ethyl amine was added to the mobile phase. Thermo ODS C18 column was used as stationary phase. The flow rate was 1mL/minute. UV detector was used at 290 nm. The linearity range for sildenafil was 5-80 μg/mL. The developed method was applied on five dietary supplements from the local market. Method II depended on the development and validation of gradient RP-HPLC method for the determination of the counterfeit sildenafil that was adulterated with paracetamol, metronidazole and/or glyburide. The mobile phase used was 50mM KH2PO4 (pH3.5): methanol (75: 25, v/v) at flow rate 0.7mL/minute for 7minutes then the mobile phase ratio was changed to (30: 70, v/v) at flow rate 1mL/minute till the end of the run. Detection was carried out using UV detector at 290 nm. The linearity ranges were 10-80, 20-70, 6-70 and 30-80 μg/mL for sildenafil, paracetamol, metronidazole and glyburide, respectively. This method was applied to synthetic mixture as well as Erec® tablet from the local market and the results were compared to those obtained by a reported method. Part III: Development and Validation of Analytical Methods for the Determination of Counterfeit Clopidogrel Bisulfate This part consists of three chapters Chapter 1: Introduction about Clopidogrel Bisulfate and its Counterfeits; Aspirin and Metronidazole This chapter includes the physical and chemical properties of clopidogrel bisulfate and its counterfeit ACS as well as pharmacological effect and literature review for the reported methods for their analysis. : UV spectrophotometric Methods for the Analysis of Clopidogrel Bisulfate Counterfeited with Aspirin and Metronidazole This chapter involves methods for the determination of clopidogrel bisulfate with ACS and metronidazole. Metronidazole was determined by direct UV spectrophotometry at 328 nm while clopidogrel bisulfate and ACS were determined by ratio derivative method at 253 and 288.6 nm, respectively using 5μg/mL metronidazole as a divisor. The linearity ranges were 10-70, 20-140 and 5-30 μg/mL for clopidogrel, ACS and metronidazole, respectively. Chapter 3: Development and Validation of HPLC Methods for Determination of Adulterated Clopidogrel Bisulfate Method I: Isocratic HPLC for determination of clopidogrel bisulfate adulterated by aspirin This chapter involves the development and validation of an isocratic RP-HPLC method for the determination of clopidogrel counterfeited with ACS. The mobile phase used was 20 mM KH2PO4 (pH2.8): methanol (30:70, v/v). Thermo ODS C18 column was used as stationary phase. The flow rate was 1.5 mL/min. UV detector was used at 220 nm. The linearity ranges were 10-70 μg/mL and 6-50 μg/mL of clopidogrel bisulfate and ACS, respectively. The method was applied on Myogrel plus® tablet (CLB and ACS). Also, it was applied on Borgavix® tablet labeled to contain 98 mg of CLB per tablet equivalent to 75 mg of clopidogrel and the results were compared with those obtained by a reported method. Method II: Isocratic HPLC for determination of clopidogrel bisulfate adulterated by metronidazole This chapter involves the development and validation of an isocratic RP-HPLC method for the determination of clopidogrel counterfeited with metronidazole. The mobile phase used was 50 mM KH2PO4 (0.1% tri-ethyl amine) (pH2.8): methanol (25:75, v/v). Thermo ODS C18 column was used as stationary phase. The flow rate was 1.5 mL/min. UV detector was used at 220 nm. The linearity ranges were 10-80 μg/mL and 5-60 μg/mL of clopidogrel bisulfate and metronidazole, respectively. The method was applied on synthetic mixture for clopidogrel and metronidazole. Also, it was applied on Borgavix® tablet and the results were compared with those obtained by a reported method. This thesis contains 153 references, 38 Figures, 69 Tables, English summary and Arabic one.