الفهرس Only 14 pages are availabe for public view
 |  | from | 179 |  |  |
| | | from | 179 | | |
Abstract
Four procedures were developed for the determination of some local anesthetic drugs, namely, benzocaine, benoxinate hydrochloride, butacaine sulphate, procaine hydrochloride and propoxycaine hydrochloride spectrofluorimetrically in pure form and in their pharmaceutical dosage forms. In addition, a study on the effect of certain additives such as silicates, cyclodextrins and surfectants on the spectral profiles of the studied drugs was also carried out. Correlation between the RFI of the measured fluorophores and certain bulkness parameters were also investigated.The thesis comprises two parts in addition to general introduction about the local anesthetic drugs especially the selected drugs and the different official and reported methods described for the assay of these drugs.Part1:-In this part, the interaction between benoxinate hydrochloride, butacaine sulphate and propoxycaine hydrochloride with sodium montmorillonite (veegum) as an example of silicates, (3-cyclodextrin ((3-CD) as an example of cyclodextrins, cetylpyridinium chloride (CPC) as an example of cationic surfactants and sodium dodecyl sulphate (SDS) as an example of anionic surfactants were investigated.The absorption spectra of benoxinate hydrochloride, butacaine sulphate and propoxycaine hydrochloride in aqueous solutions containing veegum at different pH levels showed that the veegum suspensions slightly affect the absorption profiles but significantly affect the absorption intensities of the studied drugs at certain pH values (pH * 2-5). P-CD, CPC and SDS did not give analogous effects. In aqueous solutions, pKa2 values of benoxinate hydrochloride, butacaine sulphate and propoxycaine hydrochloride were found 3.30, 3.30 and 2.90 - 3.40 respectively. However in the prescence of veegum the pKCff values were 3.50 - 3.60, 3.50 and 3.60-3.80 respectively .This shift is due to the interaction between protonated species of studied drugs and the negative veegum surface.Changes in partial molar free energy of the ionic species of the studied drugs (AGO as a result of interactions with veegum suspensions were also studied. AGBH+ values were from -0.186 to -0.399, -0.248 and from -0.530 to -0.800 Kcal./mol for benoxinate hydrochloride, butacaine sulphate and propoxycaine hydrochloride respectively, while AGB values for the same drugs were from -0.045 to 0.083, 0.011 and from -0.100 to 0.06 Kcal./mol respectively. The results indicated that, there was greater stabilization of the protonated species than the unionized species.The effect of an additional ionic solute as sodium chloride was also studied where the shift in the pKCfr values were reduced in the presence of 0.1 and 1.0 M sodium chloride solutions as the values calculated for pKeff approched again to normal pKa values.
The recovered amounts and fractions of the studied drugs bound to the veegum surface observed at pH values ranged from 2 to 12 were also studied. Part 2 :-This part concerned with the development of four simple, sensitive and reproducible spectrofluorimetric procedures for determination of the studied drugs. The methods depended upon enhancement of the native fluorescence of the studied drugs using certain solvents, solvent systems and organized media.In all cases, the procedures were optimized and applied to the analysis of local anesthetic drugs either in pure form or in pharmaceutical preparations. The calibration curves for all the studied drugs were constructed. The calibration values (a, b, r) in addition to the lower limits of detection and quantitation were calculated for all studied drugs.The proposed methods were applied to the determination of studied local anesthetic drugs in different dosage forms as single or in multicomponent formulations without interference from the commonly encountered excipients or additives. The results were compared with the official or reported methods. The t- and F- values were calculated and compared with the theoretical values, which indicate the high accuracy and good precision of the proposed procedures.Finally correlations of the RFI with certain bulkness parameters (Vx, ’% and 1%V ) of the whole drug molecules were investigated and good results obtained.