APPLICATION OF ORTHOGONAL FUNCTIONS TO CERTAIN INSTRUMENTAL METHODS OF.PHARMACEUTICAL ANALYSIS

Abstract

This part is considered an introductory part for the thesis. It contains a review article about the application of orthogonal functions to pharmaceutical analysis. This part deals. with the generation of derivative curves of I absorption spectra using orthogonal functions. It compares the derivative

curves obtained instrumentally or by mathematical differentiation to those obtained using orthogonal polynomials wi'th respect to position of optima I and curve shape. These comparisons were applied to Gaussian bands and to some selected drugs. This part also contains the improvements and increasing facilities of a BASIC program by rewriting it in Visual BASIC language. This program is used as the software for all orthogonal

functions calculations made in this part. : It deals with the generation of high order derivative curves using orthogonal functions. It was successfully proved that Pn of Pm equals Pn+m• Applying this theory on Gaussian bands, derivative curves up to D10 were obtained by this multiple convolution method. Further studies and comparisons were performed on derivative curves derived instrumentally or using orthogonal polynomials with respect to linearity, standard error of slope and reproducibility (repeatability) from D1 up to D10• Furthermore, the characteristics of the high order derivative curves were studied for phenol, ibuprofen and toluene solutions. This part deals with the derivative spectrophotometric

\ determination of ibuprofen in tablets using orthogonal polynomials. The -•• determination of ibuprofen in tablets was carried out by compensation, Amax, absorbance difference at two wavelengths, second and fourth order

orthogonal polynomials and curve fitting methods. The B.P. 2003 HPLC reference method has been carried out for comparison. The results were found to be within ±5% of the labeled amount. This complies with both the B.P. and the USP specifications for ibuprofen in tablets. Moreover, the results obtained were compared by a paired comparison method with those of the reference method.