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Abstract
This thesis is concerned with spectrofluorimetric and spectrophotometric analysis of some water-soluble vitamins in both pure forms and multivitamin preparations.
The thesis lies in 191 pages and contains 49 figures, 61 tables, 10 equations and 184 references listed as they were mentioned in the text. The present thesis comprises general introduction on the studied vitamins, which are thiamine hydrochloride, pyridoxine hydrochloride, riboflavin and cyanocobalamin. The introduction shows the structure, chemical properties, pharmacological effects and deficiency symptoms of the studied vitamins and an analytical review that contains a list of different official and reported methods.
This introduction also comprises an item explaining why this point was chosen for research, the scope of research and contribution added to this field. The thesis is divided into two main parts: Part I: Spectrofluonmetric determination of vitamin combinations.
This part contains spectrofluonmetric methods of three vitamins, which are thiamine hydrochloride, pyridoxine hydrochloride and riboflavin in addition to cyanocobalamin. The method depends on oxidation of thiamine hydrochloride by using iodine solution in the presence of sodium hydroxide, then measuring the fluorescence intensity of the produced thiochrome at Xem. 430 nm (Xcxc. 360 nm). The method was successfully applied for determination of thiamine in presence of the other studied vitamins.
All reaction variables affect the reaction conditions such as; iodine concentration, sodium hydroxide concentration, reaction and stability time and diluting solvent have been studied to optimize the conditions.
However, riboflavin and pyridoxine hydrochloride were simultaneously determined in presence of thiamine by measuring their native fluorescence in
acetate buffer (pH = 6) at X,em. 527 nm (XeXC. 457 nm) for riboflavin and X«m [415 nm (X,exc 325 nm) for pyridoxine hydrochloride.
The variables affecting the intensity of fluorescence such as; the type, pH and ionic strength of the buffer solutions, diluting solvent and the stability time have been conducted.
Also the effect of the interference due to common excipients such as glucose, sucrose, lactose, citric acid, talc and propylene glycol was investigated.
A validation study of the proposed method was carried out according to the USP XXV 2002. Linearity relationship was obtained for all the studied drugs in the concentration range of 20-500 ng ml”1 for thiamine hydrochloride and 10-120 ng ml”1 for both riboflavin and pyridoxine hydrochloride. The detection limit range was from 2.00 to 4.20 ng ml”1 while the quantitation limit range was from 6.67 to 14.00 ng ml” .
The method was successfully applied to the analysis of studied drugs in pure form, laboratory prepared mixtures and in commercial pharmaceutical preparations. Results were compared with those obtained from the official and reported methods. The t- and F- values were calculated and compared with the theoretical values, indicating high accuracy and good precision of the proposed procedures.
Part II: Spectrophotometric determination of vitamin combinations by using different chemometric methods. This part consists of two chapters: Chapter A: -
This chapter consists of spectrophotometric analysis of the studied vitamins in mixtures by using two ways of the first derivative spectra method. The first way is zero-crossing method and the second one is the first derivative of the ratio spectra method. This method depends on dividing the
! absorption spectrum of the mixture by that of one of the components. The ratio spectrum was recorded and the first derivative was calculated. The concentration of the other component of the mixture was determined from its respective calibration curve treated similarly. The variables such as AX and the divisor concentration were studied. Beer’s law was obeyed for all the studied drugs in the concentration range of 5-40 jig ml” for both thiamine hydrochloride and pyridoxine hydrochloride and 2.5-30 jig ml”1 for riboflavin and 10-70 jig ml”1 for cyanocobalamin.
For the first derivative method, the detection limit range was from 0.74 to 1.34 ^g ml”1 while the quantitation limit range was from 2.47 to 4.48 u.g ml”1.
The methods were successfully applied to analysis of studied drugs in pure form and commercial pharmaceutical multivitamin preparations. Results were compared with those obtained from the official and reported methods. The t-and F- values were calculated and compared with the theoretical values, indicating high accuracy and good precision of the proposed procedures.
Chapter B: -
This chapter describes a spectrophotometric method for the resolution of binary, ternary and quaternary mixtures of the studied vitamins using different multivariate methods. These methods are classical least squares (CLS) and principal components regression (PCR). The two methods were successfully applicable over concentration ranges of 10-40 jig ml”1 for both thiamine hydrochloride and pyridoxine hydrochloride and 2.5-30 jig ml” for riboflavin and 10-90 ug ml”1 for cyanocobalamin.
The results were statistically analyzed and compared with those obtained by applying the official and reported methods and it was found that there was no significant difference between the proposed and reported methods.