الفهرس 
Introduction and literature reviewOnly 14 pages are availabe for public view
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Abstract
Summary
The aim of this thesis is to study the interactions between certain antiviral drugs with serum albumin from different sources (bovine and human) and with certain biological matrices such as, human plasma and erythrocytes. Moreover, this thesis includes the development of different simple, sensitive and specific methods for determination of these antiviral drugs; namely ribavirin, sofosbuvir and daclatasvir in pure samples and in biological matrices.
This thesis includes five parts:
Part I: Introduction and literature review
This part is divided into two sections:
Section A: General introduction
This section comprises data about viral infections specifically, hepatitis C infection, its prevalence in Egypt and treatment. Also, it includes discussing the different forms of drug interactions and the importance of studying drug-plasma protein binding and its significance.
Section B: Literature review
In this section, structures, physicochemical properties, pharmacokinetics and assay methods reported in the literature for the studied antiviral drugs; namely ribavirin (RBV), sofosbuvir (SF) and daclatasvir(DAC) are stated.
Part II: Investigating the binding interactionofboth daclatasvir and ribavirin with serum albumin by spectroscopic methods
This part is divided into two sections:
Section A: Investigating the binding interactionof both daclatasvir and ribavirin withserum albumin by spectrophotometric method
In this section, UV-Vis spectrophotometric method was applied to determine the possibility of binding between DAC and RBV with two types of serum albumin (bovine and human). The results suggested the presence of interaction between DAC and albumin and the binding parameters were calculated such as; the values of Kd were (8.119 and 6.336 µM) for bovine serum albumin and human serum albumin, respectively. In contrast, the possibility of binding between RBV and serum albumin was excluded.
Section B: Investigating the binding interaction of both daclatasvir and ribavirin with serum albumin by conventional and synchronous spectrofluorimetric methods
In this section, the interaction between DAC and serum albumin was investigated by conventional and synchronous fluorescence spectroscopy. Results revealed the possible binding between them and the presence of static quenching in albumin spectrum. The type of bonding between them was hydrogen bonding and Van der Waals forces. Moreover, we concluded that both bovine and human serum albumin can be used in conducting binding experiments without concerning the source of albumin since no statistical significant difference was observed when comparing data obtained from conducting the same experiment using bovine and human serum albumin. Nevertheless, it was confirmed that no binding interaction is expected between RBV and albumin.
Part III: Simultaneous determination of studied antiviral drugs by two different techniques (spectrophotometric and HPLC techniques)
This part is divided into two sections:
Section A: Simultaneous determination of ribavirin and daclatasvir by two spectrophotometric methods
This section describes two spectrophotometric methods used for simultaneous determination of ribavirin and daclatasvir. For ribavirin determination, second derivative method at 211.6 nm and derivative ratio spectra method at 234 nm were proposed. For daclatasvir assay, it was determined by second derivative method at 310.6 nm and from its zero-order spectrum at 312.2 nm. The two proposed methods were applied successfully and validated for determination of ribavirinand daclatasvir in their pure forms with concentration ranges 0.60-24.00 and1.00-22.00 µg/mL for RBV and DAC, respectively. RBV was determined with accuracies 99.48 ± 1.06 and 99.99 ± 1.66 using second derivative and derivative ratio spectra methods, respectively. While, DAC determined with accuracies 100.59 ± 0.95 and 100.51 ± 1.70 using second derivative and zero-order spectrum methods, respectively. The two methods were successfully applied for the determination of the two drugs in spiked human plasma using liquid-liquid extraction showing good recovery percentages. Finally, the proposed methods were statistically compared to previously reported methods for determination of the studied drugs and revealed no significant difference.
Section B: Simultaneous determination and bioanalytical validation of ribavirin, sofosbuvir and daclatasvir by HPLC method
In this section, RP-HPLC method was applied for simultaneous determination of ribavirin, sofosbuvir and daclatasvirusing propyl paraben as internal standardin human plasma. The used column was C18 and the initial gradient conditions were 100% water for 2 min, decreased to 45% and maintained at this concentration (45% water: 55% acetonitrile) till the end of the run and the flow rate was set at 1 mL/min. Detection was carried out at 207 nm for ribavirin, 260 nm for sofosbuvir while, for daclatasvir at 312 nm. Method was successfully validated according to the FDA bioanalytical validation guidelines in human plasma and applied to concentration ranges 0.50 – 80.00, 0.10 – 40.00 and 0.50 – 80.00 µg/mL for RBV, SF and DAC, respectively. The obtained accuracy results were 101.97 ± 3.14, 98.02 ± 1.46 and 103.15 ± 3.32 for RBV, SF and DAC, respectively.
Part IV: Determination of ribavirin by spectrofluorimetric and spectrophotometric methods
This part is divided into two sections:
Section A: Determination of ribavirin in presence of sofosbuvir by derivative ratio spectra synchronous fluorescence spectroscopy method
In this section, ribavirin was determined in presence of sofosbuvir using derivative ratio spectra synchronous fluorescence. The presence of any interactions between ribavirin and different organized media (e.g. surfactants and macromolecules) was studied and their effect on its relative fluorescence as well.Ribavirin was determined by measuring its relative fluorescence of derivative ratio spectra at 435 nmusing ∆λ = 70 nm in its pure form at concentration range 0.08 – 10.00 µg/mL and resulting in accuracy 100.84 ± 1.30. The method wassuccessfully applied for the determination of RBV in spiked human plasma using protein precipitation extraction method showing good recovery percentages.
Section B: Determination and bioanalytical validation of ribavirin in erythrocytes by spectrophotometric method
Since, a possible interaction between ribavirin and erythrocytes may occur, leading to hemolysis which may cause hemolytic anemia during prolonged ribavirin therapy. This section comprises a UV-Vis spectrophotometric method for determination of ribavirin in erythrocytes at 232.4 nm. Extraction was achieved using protein precipitation by perchloric acid. The method was applied successfully and validated according to the FDA bioanalytical validation guidelines and applied to concentration range 10.00 – 50.00 µg/mL with accuracy 101.24 ± 0.68.
Part V: General discussion
This part includes general discussion about all the developed methods for determination of studied drugs and ANOVA test results performed for comparing the proposed methods to the reported ones.
The thesis contains 51 figures, 45 tables, 142 references and ends with Arabic summary.