Comparative Study of Different Derivative Spectrophotometric Techniques for the Analysis and Separation of Metformin, Empagliflozin, and Glimepiride

Background: In some cases, lifestyle changes are not enough to keep type 2 diabetes under control, so there are several medications that may help. Metformin can lower your blood sugar levels, Glimepiride makes more insulin, whereas Empagliflozin prevents the kidneys from reabsorbing sugar into the blood and sending it out in the urine. Methods: Mean centering, double divisor, ratio spectra-zero crossing, and successive derivative were applied for the estimation of metformin, empagliflozin, and glimepiride respectively, in their prepared laboratory mixtures and in pharmaceutical tablets, without prior chemical separation. The absorption spectra of the mentioned drugs were recorded in the range of 200-400nm. Results: These methods were linear over concentration ranges of 1.0-10, 2.5-30, and 1.0-10 μgmL-1 of metformin, empagliflozin, and glimepiride respectively. Mean centering for metformin was measured at 234 and 248 nm, while empagliflozin and glimepiride had amplitude values at 276 and 262 nm, respectively. The derivative of double divisor was measured at 234, 278, and 288 nm for metformin, empagliflozin and glimepiride, respectively. The ratio of spectra-zero crossing was quantified at amplitude values of the analytical signal at 234 and 274 nm for metformin and empagliflozin, respectively, whereas glimepiride was determined at 242 and 286 nm. The successive ratio of metformin, empagliflozin, and glimepiride was determined at 284, 242, and 266 nm, respectively. Conclusion: The methods are validated according to the ICH guidelines where accuracy, precision and repeatability are found to be within the acceptable limit. The methods were studied and optimized. Upon validation linearity, precision, accuracy, LOD, LOQ and selectivity were proved to be operative for the analysis of specified drugs in pharmaceutical dosage configuration. Statistical illustration was done between the suggested methods with the reported methods with consideration to accuracy and precision. No significant difference was found by student’s t-test, F-test and one-way ANOVA.

DERIVATIVE UV SPECTROSCOPIC APPROACHES IN MULTICOMPONENT ANALYSIS–A REVIEW

The spectrophotometric multi-component analysis involves spectrum recording and mathematical equations. However, spectral interference poses a major limitation when mixture samples are encountered. To overcome this derivative spectrophotometry (DS) has been introduced for the resolution of overlapping peaks. In this review modified methods like derivative quotient spectra, double divisor ratio spectra derivative method, double divisor means centering of ratio spectra method, derivative subtraction coupled with the constant multiplication method (DS-CM), amplitude subtraction (AS), modified amplitude subtraction (MAS), amplitude factor method (P-Factor), amplitude modulation method (AM), amplitude summation method (A-Sum), simultaneous derivative ratio spectrophotometry (S1DD), derivative compensation ratio via regression equation, differential dual wavelength (D1 DWL), differential derivative ratio (D1DR), successive derivative subtraction method (SDS) and derivative transformation (DT) of derivative spectrophotometry theories and applications are reviewed. These methods were applied to solve different complex pharmaceuticals mixtures. These developed methods were simple and cost-effective.

Novel Approach for the Simultaneous Determination of Carbinoxamine Maleate, Pholcodine, and Ephedrine Hydrochloride Without Interference from Coloring Matter in an Antitussive Preparation Using Smart Spectrophotometric Methods

The presence of coloring matters in syrups usually interferes with the spectrophotometric determination of active pharmaceutical ingredients. A novel approach was introduced to eliminate the interference of sunset yellow (coloring matter) in Cyrinol syrup. Smart, simple, accurate, and selective spectrophotometric methods were developed and validated for the simultaneous determination of a ternary mixture of carbinoxamine maleate, pholcodine, and ephedrine hydrochloride in syrup. Four of the applied methods used ratio spectra: successive derivative subtraction coupled with constant multiplication, successive derivative of ratio spectra, ratio subtraction coupled with ratio difference, and ratio spectra continuous wavelet transforms zero-crossing. In addition, a method that was based on the presence of an isosbestic point, the amplitude summation method, was also established. A major advantage of the proposed methods is the simultaneous determination of the mentioned drugs without prior separation steps. These methods were successfully applied for the determination of laboratory-prepared mixtures and a commercial pharmaceutical preparation without interference from additives, thus proving the selectivity of the methods. No significant difference regarding both accuracy and precision was observed upon statistical comparison of the results obtained by the proposed methods with each other and with those of official or reported ones.

SIMULTANEOUS ESTIMATION OF ERDOSTEINE, GUAIPHENESIN AND TERBUTALINE SULPHATE IN SYRUP FORMULATION BY TWO UV SPECTROPHOTOMETRIC METHODS

Two simple, rapid and economic UV spectrophotometric methods, namely successive ratio derivative and double divisor ratio spectra methods, have been developed for the simultaneous estimation of ternary mixtures of erdosteine, guaiphenesin and terbutaline sulphate without preceding separation steps. Method I is based on successive derivative of ratio spectra in two steps, whereas method II is based on convolution of double divisor ratio spectra, obtained by dividing the absorption spectrum of the ternary mixture by a standard spectrum of two of the three compounds in the mixture. All the drugs exhibited good linearity over the reported concentration range with acceptable correlation coefficient. The methods were validated according to ICH guidelines for the evaluation of accuracy, precision, sensitivity. The obtained relative standard deviation i.e. less than 2%, demonstrated that the proposed methods were accurate and precise and can be employed for routine analysis in quality control laboratories, eliminating the need of prior separation of the pharmaceutical mixtures.