Determination of Cephalexin Monohydrate in Pharmaceutical Dosage Form by Stability-Indicating RP-UFLC and UV Spectroscopic Methods

Highly Specific Voltammetric Detection of Cephalexin in Tablet Formulations and Human Urine Samples Using a Poly(2,4,6-2',4',6'-hexanitrodiphenylamine)-Modified Glassy Carbon Electrode

β-Lactam antibiotics are employed to treat bacterial illnesses. Despite a high level of clinical success, they have encountered serious resistance that demands a high-dose regimen and a new pharmacokinetic combination. This requires continuous monitoring of their levels in pharmaceutical and biological samples. In this study, an electrochemical sensor was developed for the determination of cephalexin (CLN) in pharmaceutical formulations and biological fluid samples. The sensors were developed by modifying a glassy carbon electrode (GCE) using a conducting polymer (dipicrylamine) by potentiodynamic electropolymerization. Characterization (using cyclic voltammetry and electron impedance spectroscopy) results revealed modification of the electrode surface, leading to an enhanced effective electrode surface area and their conductivity. The appearance of an irreversible oxidative peak at much-reduced potential with 5-fold current enhancement at a poly(dipicrylamine)-modified glassy carbon electrode (poly(DPA)/GCE) verified the electrocatalytic role toward CLN. Under optimized conditions, a wider linear concentration range (5 × 10-8 to 3.0 × 10-4 M), lowest limit of detection (LoD) (2.5 nM), detected amount of each tablet brand above 97.00% of the labeled value (showing excellent agreement between the detected amount and company label), and excellent % recovery results in pharmaceutical and biological samples were obtained with an excellent interference recovery error of less than 4.05%. Its excellent accuracy, selectivity, reproducibility, and stabilities and only requiring a simple electrode modification step combined with its readily available and nontoxic modifier, which sets it apart from most previously reported methods, have validated the present method's potential applicability for determining CLN in biological and pharmaceutical samples.

Potentiodynamic Poly(resorcinol)-Modified Glassy Carbon Electrode as a Voltammetric Sensor for Determining Cephalexin and Cefadroxil Simultaneously in Pharmaceutical Formulation and Biological Fluid Samples

This study covers the development of a fast, selective, sensitive, and stable method for the simultaneous determination of cephalosporins (cephalexin (CLN) and cefadroxil (CFL)) in biological fluids and tablet samples using potentiodynamic fabrication of a poly(resorcinol)-modified glassy carbon electrode (poly(reso)/GCE). The results of cyclic voltammetry and electrochemical impedance spectroscopy supported the modification of the GCE by a polymer layer that raised the electrode surface area and conductivity. At the poly(reso)/GCE, an irreversible oxidative peak with four- and fivefold current enhancement for CLN and CFL, respectively, at a substantially lower potential demonstrated the catalytic action of the modifier. Under optimized solution and parameters, the peak current response at the poly(reso)/GCE revealed a linear dependence on the concentration of CLN and CFL within the range 0.1-300 and 0.5-300 μM, respectively, with a limit of detection (LoD) of 3.12 and 8.7 nM, respectively. The levels of CLN in four selected tablet brands and CFL in two tablet brands were in the vicinity of 91.00-103.65% and 97.7-98.83%, respectively, of their nominal values. The recovery results for CLN in pharmaceutical samples were in the range of 99.00-100.67% and for CFL 97.9-99.75% and for blood serum and urine samples 99.55-100.55% and 99.33-100.34% for CLN and 97.13-100.60% and 96.73-102.50% for CFL, respectively. Interference recovery results with errors less than 4.81%, lower LoD, wider dynamic range, excellent recovery results, and good stability of the modifier compared to those for the previously reported methods validated the use of the poly(reso)/GCE for determining CLN and CFL simultaneously in various real samples.

Simultaneous Quantification of Cephalexin and Sodium Benzoate in their Dosage forms by high analytical technique. Application of Lean Six Sigma and In-Vitro Dissolution studies

OBJECTIVES

The aim of the present work is to develop and validate a novel and simple Chromatographic and MCR methods for simultaneous quantification of cephalexin (CPH) and sodium benzoate (SDM) in their dosage form and application of Lean Six Sigma (LSS) to reduce variation and improve quality.

METHODS

Isocratic separation is performed using Agilent XDB-C8 (4.6mm×250mm) 5μm, with a mobile phase consisting of acetonitrile: water (30: 70, v/v) containing 0.1% orthophosphoric acid (OPA) at flow rate of 1.5mL/min and wavelength 254nm with injection volume of 20μL for HPLC and Agilent ZORBAX SB-C18 column (50mm×2.1mm, 1.8μm particle size) at flow rate 0.25mL/min, injection volume 0.8μL for UPLC. MCR spectrophotometric method is successfully applied for resolving spectral overlap of drugs at 240nm and 250nm for CPH and SDM, respectively. Comparative invitro dissolution studies are established on Generic product; Rivalexin and Lexin 250mg/5mL, consequently it had been considered equivalent and like the innovator product; Cephalexin USP 250mg/5mL using different USP media.

RESULTS

Good Linearity and recovery are achieved over the concentration range of 10-300, and 5-50μg/mL for the studied drugs. Process Capability Index (Cpk) is >1.33 and still capable during all stages of the product release.

CONCLUSION

The proposed method is accurate and could be applied to dosage form and LSS to interpret the data of quality attributes.

A Simple and Specific Stability- Indicating RP-HPLC Method for Routine Assay of Adefovir Dipivoxil in Bulk and Tablet Dosage Form

A simple and reliable stability-indicating RP-HPLC method was developed and validated for analysis of adefovir dipivoxil (ADV).The chromatographic separation was performed on a C₁₈ column using a mixture of acetonitrile-citrate buffer (10 mM at pH 5.2) 36:64 (%v/v) as mobile phase, at a flow rate of 1.5 mL/min. Detection was carried out at 260 nm and a sharp peak was obtained for ADV at a retention time of 5.8 ± 0.01 min. No interferences were observed from its stress degradation products. The method was validated according to the international guidelines. Linear regression analysis of data for the calibration plot showed a linear relationship between peak area and concentration over the range of 0.5-16 μg/mL; the regression coefficient was 0.9999and the linear regression equation was y = 24844x-2941.3. The detection (LOD) and quantification (LOQ) limits were 0.12 and 0.35 μg/mL, respectively. The results proved the method was fast (analysis time less than 7 min), precise, reproducible, and accurate for analysis of ADV over a wide range of concentration. The proposed specific method was used for routine quantification of ADV in pharmaceutical bulk and a tablet dosage form.

Photocatalytic activity of NiS, NiO and coupled NiS–NiO for degradation of pharmaceutical pollutant cephalexin under visible light

Highly efficient visible light cephalexin degradation obtained by photocatalyst prepared by immobilization of NiS, and NiO on the Fe₃O₄@PPY support.