Ahmed El-Olemy

Spectroflurimetric estimation of the new antiviral agent ledipasvir in presence of sofosbuvir

A spectroflurimetric method has been developed and validated for the selective quantitative determination of ledipasvir in presence of sofosbuvir. In this method the native fluorescence of ledipasvir in ethanol at 405nm was measured after excitation at 340nm. The proposed method was validated according to ICH guidelines and show high sensitivity, accuracy and precision. Furthermore this method was successfully applied to the analysis of ledipasvir in pharmaceutical dosage form without interference from sofosbuvir and other additives and the results were statistically compared to a reported method and found no significant difference.

Different spectrophotometric methods applied for the analysis of simeprevir in the presence of its oxidative degradation product: Acomparative study

Five simple spectrophotometric methods were developed for the determination of simeprevir in the presence of its oxidative degradation product namely, ratio difference, mean centering, derivative ratio using the Savitsky-Golay filters, second derivative and continuous wavelet transform. These methods are linear in the range of 2.5-40μg/mL and validated according to the ICH guidelines. The obtained results of accuracy, repeatability and precision were found to be within the acceptable limits. The specificity of the proposed methods was tested using laboratory prepared mixtures and assessed by applying the standard addition technique. Furthermore, these methods were statistically comparable to RP-HPLC method and good results were obtained. So, they can be used for the routine analysis of simeprevir in quality-control laboratories.

Application of TLC Densitometric Method for Simultaneous Estimation of the Newly Co-formulated Antiviral Agents Ledipasvir and Sofosbuvir in Their Tablet Dosage Form

Abstract Ledipasvir (LED) and Sofosbuvir (SOF) are newly approved antiviral agents co-formulated for treatment of hepatitis C virus. In the present work; an accurate and precise TLC densitometric method has been developed for simultaneous determination of LED and SOF in their bulk and dosage form. The proposed method based on determination of the UV-visualized bands after TLC separation of LED and SOF. The studied drugs were quantitatively separated on 60 F254 silica gel plates using mobile phase consists of (90% ethyl acetate: 9% hexane: 1% tri ethylamine by volume) with UV detection at 250 nm. The studied drugs were satisfactorily resolved with retention factor (Rf) values of 0.09 ± 0.005 and 0.23 ± 0.01 for LED and SOF, respectively. The proposed method has been validated according to ICH guidelines and show high sensitivity, accuracy and precision and the results were statistically compared to reported method.

Application of different spectrophotometric methods for simultaneous determination of elbasvir and grazoprevir in pharmaceutical preparation

The first three UV spectrophotometric methods have been developed of simultaneous determination of two new FDA approved drugs namely; elbasvir and grazoprevir in their combined pharmaceutical dosage form. These methods include simultaneous equation, partial least squares with and without variable selection procedure (genetic algorithm). For simultaneous equation method, the absorbance values at 369 (λmax of elbasvir) and 253nm (λmax of grazoprevir) have been selected for the formation of two simultaneous equations required for the mathematical processing and quantitative analysis of the studied drugs. Alternatively, the partial least squares with and without variable selection procedure (genetic algorithm) have been applied in the spectra analysis because the synchronous inclusion of many unreal wavelengths rather than by using a single or dual wavelength which greatly increases the precision and predictive ability of the methods. Successfully assay of the drugs in their pharmaceutical formulation has been done by the proposed methods. Statistically comparative analysis for the obtained results with the manufacturing methods has been performed. It is noteworthy to mention that there was no significant difference between the proposed methods and the manufacturing one with respect to the validation parameters.

Stability-indicating HPLC-DAD Method for the Determination of Simeprevir

Abstract Simeprevir is a novel direct acting antiviral agent against hepatitis C virus. In the present work, a rapid, specific and reproducible reversed phase high performance liquid chromatography with diode array detection (HPLC-DAD) method has been developed and validated for the determination of simeprevir in the presence of its forced degradation products. The drug was subjected to variable stress conditions including hydrolysis, oxidation, thermal and photolysis. The drug was found to be labile to acidic hydrolysis, basic hydrolysis, oxidation and photolysis but stable in thermal and neutral hydrolytic conditions. Successful chromatographic separation of simeprevir was achieved on Discovery® HS C18 column at a flow rate of 1 mL/ min using mobile phase of acetonitrile. The eluents were monitored by the diode array detector and peak area values were measured at 288 nm. The validity of the method was assessed by evaluating accuracy, precision, specificity and robustness. The linear regression analysis data for the calibration curve shows a good relationship in the range of 1.5 - 45 μg/mL. The developed method was successfully applied for the estimation of simeprevir in its commercial dosage form and could be used for the routine analysis of the studied drug in quality control laboratories.

Comparative Study Between Zero-Order Spectra-Processing and Ratio Spectra-Manipulating Methods Applied for the Determination of Isoxsuprine Hydrochloride in the Presence of Its Oxidative Degradation Product

Four accurate, precise, and validated stability-indicating spectrophotometric methods handling either zero-order spectra or ratio spectra have been developed and compared for the analysis of isoxsuprine hydrochloride (ISX) in the presence of its oxidative degradation product. The first two methods processed zero-order spectra, namely graphical absorbance ratio or Q-Analysis and area under the curve, whereas the third and fourth methods manipulated ratio spectra, namely the ratio difference spectrophotometric method and derivative ratio. The proposed methods showed good linearity in the range of 2-23 µg/mL. The methods were tested for specificity using laboratory-prepared mixtures containing the drug and its degradation product. The proposed methods were applied for the determination of ISX in Vascular tablets and the obtained results were acceptable, with small percentage RSD values. The validity of the proposed procedures was further assessed by applying the standard addition technique, which showed no interference from excipients. The obtained results were statistically compared with those obtained by the reported method, showing no significant differences when t- and F-tests were applied.

Comparative Study of Different Spectrophotometric Methods for Determination of Phenazopyridine Hydrochloride in the Presence of its Oxidative Degradation Product

Abstract Four stability indicating spectrophotometric methods have been developed for selective determination of phenazopyridine hydrochloride (PAP) in the presence of its oxidative degradation product 2,3,6-triaminopyridine (TAP). The described spectrophotometric methods namely; first derivative (1D), ratio difference spectrophotometric method (RDSM), first derivative of ratio spectra (1DD, and dual wavelength (DW). For 1D method, the peak amplitudes at 370 nm were measure, while the difference between 428 and 276 nm in peak amplitudes were measured for RDSM. On the other hand, the peak amplitudes at 360 nm were measured for 1DD, while the difference in the absorbance between 425 and 256 nm were measured for DW. The regression analysis data for the calibration plots of PAP showed a good linear relationship over the concentration range of 1-14 μg/ml by the four proposed methods. The proposed methods have been successfully applied to the assay of PAP in pharmaceutical formulation. Also, the obtained results have been statistically compared to a reported HPLC method to give a conclusion that there is no significant difference between the investigated methods and the reported one with respect to validation parameters.

Simultaneous Spectrophotometric Determination of Elbasvir and Grazoprevir in a Pharmaceutical Preparation

Three UV spectrophotometric methods have been developed for the simultaneous determination of two new Food and Drug Administration-approved drugs, elbasvir (EBV) and grazoprevir (GRV), in their combined pharmaceutical dosage form. These methods include dual wavelength (DW), classic least-squares (CLS), and principal component regression (PCR). To achieve the DW method, two wavelengths were chosen for each drug in a way to ensure the difference in absorbance was zero from one drug to the other. GRV revealed equal absorbance at 351 and 315 nm, for which the distinctions in absorbance were measured for the determination of EBV. In the same way, distinctions in absorbance at 375 and 334.5 nm were measured for the determination of GRV. Alternatively, the CLS and PCR models were applied to the spectra analysis because the synchronous inclusion of many unreal wavelengths rather than using a single wavelength greatly increased the precision and predictive ability of the methods. The proposed methods were successfully applied to the assay of these drugs in their pharmaceutical formulation. The obtained results were statistically compared with manufacturing methods. The results conclude that there was no significant difference between the proposed methods and the manufacturing method with respect to accuracy and precision.

High Performance Liquid Chromatography Based on Computational Study for the Determination of Etilefrine Hydrochloride in the Presence of its Oxidative Degradation Product

Abstract A simple, sensitive, specific and accurate stability indicating HPLC method was developed for the determination of etilefrine hydrochloride (ETF) in presence of its oxidative degradate. Computational and theoretical studies were done electronically and geometrically to investigate the affinity of ETF and its oxidative degradate to the stationary phase. The analysis was carried out on an ODS SUPELCO C18 (25 cm X 4.6 mm, 5 μm particle size) using a mobile phase consisting of [0.1M phosphate buffer, pH 4: acetonitrile (30:70, v/v)]. The analysis was performed at ambient temperature with a flow rate of 1 mL/min and UV detection at 220 nm. The proposed method can selectively analyzes the drug in presence of up to 80% of its oxidative degradate with mean recovery ± RSD % of 99.54±0.503. The proposed method was extensively validated according to the ICH guidelines and used for estimation of ETF in tablets and the obtained results were statistically compared with those of the reported method by applying t-test and F-test at 95% confidence level and no significant difference was observed regarding accuracy and precision.

Different Spectrophotometric Methods Manipulating Ratio Spectra Applied for the Analysis of Aclidinium in Duaklir® Genuair® Inhalation Powder

Two simple, accurate, and selective spectrophotometric methods were developed to determine aclidinium in the presence of formoterol as interferent compound in Duaklir Genuair inhalation powder. The methods under study are ratio derivative and ratio subtraction spectrophotometric methods. These methods are based on different mathematical processing of the obtained ratio spectra. The methods are linear over the concentration range of 5–50 µg/mL for aclidinium and validated according to the ICH guidelines. The accuracy and precision are found to be within the acceptable limits and assessed by applying the standard addition technique. The specificity of the proposed methods was tested using laboratory-prepared mixtures. Furthermore, the methods were statistically compared to the reported RP-HPLC method, and good results were obtained.