الفهرس 
General IntroductionOnly 14 pages are availabe for public view
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Abstract
Two PMS antibiotics medications, CS and Poly B were quantified spectrofluorimetrically and spectrophotometrically using a variety of techniques. The submitted thesis is divided into five parts:
Part I: General introduction
This section primarily provided a general introduction to the medications under screening. Such as mechanism of action, medicinal indications, pharmacokinetics, and structural properties. Furthermore, an analytical review of the reported methodologies for quantifying the drugs under consideration in their pharmaceutical formulations, and biological fluids was displayed. Eventually, the goal of the described thesis was completely mentioned.
Part II: Hantzsch reaction for PMS assay in Market Dosage Form and biological fluids
The described approach was a cost-effective, and sensitive approach for quantifying CS in bulk and commercial dosage forms. Also, the most selective one for investigating Poly B without interfering with other basic excipients in tedious dosage forms such as ointment. The methodology relied on a condensation reaction between acetylacetone/formaldehyde and the primary amino moiety of non-fluorescent cited drugs in Teorell and Stenhagen buffer. For CS and Poly B, RFI values were measured at λem 460 nm (λex = 402 nm) and λem 471 nm (λex = 402 nm), respectively. The linearity of CS varied from 200 to 400 and that of Poly B from 100 to 3000 ng mL-1. LOD and LOQ for CS were 40.91 and 123.99 ng mL-1 and 27.16 and 82.30 ng mL-1 for Poly B. Owing to its high sensitivity, it could be applied to spike with human plasma with %R 98.24 ±1.34 for CS and 97.42 ±1.46 for Poly B.
Moreover, it was considered the first approach for assaying intravenous dosage forms of PMS, Colomycin®, and Paximid® vials, with a high %R. Finally, the proposed technique was assessed for robustness, precision, and accuracy, indicating that it was suitable for routine analysis. Among the merits of the studied method were the instrument’s availability and the omission of an extraction procedure with huge consumption of organic solvents. So, the proposed work could be easily applied to routine quality control assays for studied drugs. These features are not commonly found in other reported chromatographic techniques for the assay of the cited medications.
Part III. Development of a facile and rapid fluorimetric measurement of PMS via reaction with fluorescamine; Biological fluid application
A facile, rapid, and ultrasensitive fluorimetric quantification of PMS in market formulations and human plasma was implemented. A reaction between fluorescamine and the aliphatic amino moiety found in both drugs was performed in a slightly alkaline borate buffer (pH 8.5) resulting in highly fluorescent products measured at λem 460 (after λex 390.5 nm). Linear calibration curves were constructed over the concentration range of 70–1800 ng mL-1 for Poly B and 100 to 1400 ng mL-1 for CS. And values of r = 0.9998 or 0.9997 and r2 = 0.9997 or 0.9994 were calculated for poly B and CS, respectively. The ultra-sensitivity of the proposed method was demonstrated by the very low LOQ values of 67.56 ng mL-1 and 94.89 ng mL-1 for poly B and CS, respectively. The investigated medications were quantified in their parenteral dosage forms by the suggested methodology. Furthermore, the researched medications could be successfully spiked with human plasma owing to the approach’s high sensitivity.
Finally, the reaction ratio between PMS and fluorescamine was calculated using Job’s approach. The mole fraction was plotted against the RFI, and the best one was 0.5 for both investigated drugs. Accordingly, the molar ratio of PMS and fluorescamine reaction was 1:1. Without the need for costly equipment and massive volumes of organic solvents. The estimation of the researched drugs in quality control laboratories was readily fast and simple through the described approach.
Part IV. New validated spectrofluorimetric procedure for PMS analysis via reaction with Ninhydrin; Application to Content uniformity testing.
This part included a robust and sensitive fluorimetric assay for the analysis of PMS in different market samples. The listed medications were condensed with 2,2 dihydroxyindan-1,3 dione in presence of Phenylacetaldehyde utilizing Teorell& Steinhagen buffer. The fluorescent products were estimated at λem = 474 nm after λex = 390 nm for CS and λem= 475.5 nm after λex = 386 nm for Poly B. Over the following ranges (0.2–3 µg mL-1) and (0.2–2.4 µg mL-1) for Poly B and CS, respectively, the yielded calibration plots looked rectilinear.
The estimated LOD and LOQ were 0.051 & 0.154 and 0.062 & 0.187 µg mL-1 for CS and Poly B, respectively. The methodology was employed to quantify pharmaceutical formulations comprising the researched medications with a high %R. Moreover, related to CS, content uniformity testing was successfully employed as a new approach not found in the previously published spectrofluorimetric methods.
Part V. Full green screening of Polymyxins utilizing Erythrosine B: Application to pure and parenteral dosage forms.
In the current research, PMS were quantified via a reliable, sensitive, and non-extracting spectrophotometric approach that relied on ion-pair complexes’ formation with xanthene dye, EB. Without using any organic solvents, the pink color of the created ion-pair complexes was detected at λ = 540 nm. To achieve the highest absorbance values, the optimum conditions were established by screening the color interaction between EB and the investigated drugs. For CS and Poly B, respectively, Beer-law Lambert’s was illustrated at concentration ranges of 1-6, and 1-9 µg mL-1. The technique was approved following ICH recommendations. The suggested approach had a good %R and was successfully employed to determine both the cited medications in their bulk and parenteral dosage forms.
Finally, the reaction ratio between PMS and EB was calculated using Job’s approach. According to the study, the reaction molar ratio of PMS with EB was 1:1. The yielded compounds were freely water soluble, so no need for organic solvents, making the suggested technique safer for the environment than previously described ones.
Moreover, organic solvent extraction is not required, therefore, the generated ion-pair complexes could be directly measured. Interestingly, the suggested approach was considered the first colorimetric approach for quantification of the cited medications in their intravenous dosage forms. Owing to the method’s greenes and simplicity, it could be efficiently employed in quality control laboratories instead of the previously reported spectrofluorimetric and HPLC techniques.