Amoxicillin

Quantitative analysis of solid dosage forms of cefixime using Raman spectroscopy

Quantification of antibiotics is of significant importance because of their use in the prevention and treatment of different diseases. Cefixime (CEF) is a cephalosporin antibiotic that is used against bacterial infections. In the present study, Raman spectroscopy has been applied for the identification and quantification of Raman spectral features of cefixime with different concentrations of Active Pharmaceutical Ingredient (API) and excipients in solid dosage forms. The changes in Raman spectral features of API and excipients in the solid dosage forms of cefixime were studied and Raman peaks were assigned based on the literature. Multivariate data analysis techniques including the Principal Component Analysis (PCA) and Partial Least Squares Regression analysis (PLSR) have been performed for the qualitative and quantitative analysis of solid dosage forms of cefixime. PCA was found helpful in differentiating all the Raman spectral data associated with the different solid dosage forms of cefixime. The coefficient of determination (R²), mean absolute error (MAE), and mean relative error (MRE) for the calibration data-set were 0.99, 0.72, and 0.01 respectively and for the validation data-set were 0.99, 3.15, and 0.02 respectively, that shows the performance of the model. The root mean square error of calibration (RMSEC) and root mean square error of prediction (RMSEP) were found to be 0.56 mg and 3.13 mg respectively.

Simple and reliable extraction and a validated high performance liquid chromatographic assay for quantification of amoxicillin from plasma

This study presents the development of an efficient extraction protocol for amoxicillin from plasma with improved solubility and stability using pH control. Solubility and stability of amoxicillin in commonly used extraction solvents were determined using a newly developed stability-indicating high-performance liquid chromatography (HPLC) method. Following this, protein precipitation (PP) mediated sample purification protocol was developed and validated along with the HPLC method for the extracted amoxicillin from rabbit plasma. The protocol was applied in a pharmacokinetic study in rabbits. A five-fold increase in solubility and two-fold increase in stability of amoxicillin was found by addition of acetate buffer (0.1 M, pH 5.0) in acetonitrile. PP mediated extraction protocol containing acetate buffer-acetonitrile (1:18 v/v) resulted in an extraction recovery of >80% for all the samples. The HPLC assay following extraction was found linear (R²   >0.9999) over the range of 0.2-20 µg/mL with a lower limit of quantification of 0.2 µg/mL. The accuracy of the quality control samples was found between 97-115% and the relative standard deviation (RSD) was found to be below 6% for all samples. The samples were stable in the mobile phase (pH 5.0) for 72 h post-extraction. Amoxicillin-spiked plasma samples were found stable for up to three freeze-and-thaw cycles but, nearly 50% samples had degraded following storage for two months at -20 °C. Pharmacokinetic analysis indicated a half-life of amoxicillin of nearly 1 h following intravenous injection in rabbits, which is similar to that in humans. Thus, a simple and repeatable, extraction protocol was developed using pH control for quantification of amoxicillin from plasma based on its physicochemical properties.

Optimizing of pharmaceutical active compounds biodegradability in secondary effluents by β-lactamase from Bacillus subtilis using central composite design

Biodegradation of pharmaceuticals active compounds (PACs) in secondary effluents by using B. subtilis 2012WTNC as a function of β-lactamase was optimized using response surface methodology (RSM) designed by central composite design (CCD). Four factors including initial concentration of bacteria (1-6 log₁₀ CFU mL^-1), incubation period (1-14 days), incubation temperature (20-40 °C) and initial concentration of PACs (1-5 mg L^-1) were investigated. The optimal operating factors for biodegradation process determined using response surface methodology (RSM) was recorded with 5.57 log₁₀ CFU mL^-1 of B. subtilis, for 10.38 days, at 36.62 °C and with 4.14 mg L^-1 of (cephalexin/amoxicillin) with R² coefficient of 0.99. The biodegradation was 83.81 and 93.94% respectively. The relationship among the independent variables was significant (p < 0.05) with 95% of confidence level at the best operating parameters. The bioassay for PACs after the degradation process revealed that no residual antibiotic activity was detected of amoxicillin and cephalexin against E. coli and S. aureus after degradation using B. subtilis which reflects the higher potential of bacteria to biodegrade PACs in secondary effluents. B. subtilis has the potential for biodegradation of PACs in the secondary effluents.

Application of 1H nuclear magnetic resonance spectroscopy to the analysis of beta-lactam antibiotics and their common degradation products

The (1)H NMR characteristics of the majority of penicillin and cephalosporin beta-lactam antibiotics in world-wide clinical use are presented. Some of the data are novel and include several high resolution (220, 400 MHz) spectra. The influence of solvent and ionisation state upon spectral parameters is discussed and a scheme of analysis proposed for identifying an unknown beta-lactam sample. Spectral features of common degradation products of benzylpenicillin and other penicillins are provided and the use of (1)H NMR spectroscopy in monitoring the breakdown of penicillin antibiotics described. Other aspects discussed are NMR studies of the stereochemistry, association and protein binding of beta-lactam antibiotics.

Solid-state fluorescence of the trihydrate phases of ampicillin and amoxicillin

The purpose of this work was to study the effects of crystal structure on the solid-state photoluminescence of the trihydrate phases of ampicillin and amoxicillin, and to contrast these spectra with analogous spectra obtained on the molecules dissolved in a solution phase. The polymorphic identity of the analytes was established using x-ray powder diffraction and Fourier transform infrared absorption spectroscopy, and the solid-state luminescence spectra obtained under ambient conditions. It was found that the solid-state excitation and emission spectra of ampicillin trihydrate and amoxicillin trihydrate were dominated by energy transfer and exciton effects, which were manifested as decreases in the energy of the excitation and emission bands of the solid-state systems relative to those of the free molecule in solution. The photoluminescence data revealed that in spite of the known structural similarity of ampicillin trihydrate and amoxicillin trihydrate, the magnitude of the Davydov splitting, and the degree of band energy shifting differed between the 2 systems. This finding indicates that the small differences in crystal structure existing between the 2 compounds leads to measurable differences in the patterns of energy transfer.