Pharmaceuticals and related drugs

Review for Analytical Methods for the Determination of Sodium Cephalothin

Infections are the second leading cause of global morbidity and mortality, therefore it is highly important to study the antimicrobial agents such as cephalosporins. Cephalothin, an antimicrobial agent that belongs to the class of cephalosporins, has bactericidal activity and it is widely used in the Brazilian health system. In literature, some analytical methods are found for the identification and quantification of this drug, which are essential for its quality control, which ensures maintaining the product characteristics, therapeutic efficacy and patient's safety. The aim of this article is to review the available information on analytical methods for cephalothin. Thus, this study presents a literature review on cephalothin and the analytical methods developed for the analysis of this drug in official and scientific papers. It is essential to note that most of the developed methods used toxic and hazardous solvents, which makes necessary industries and researchers choose to develop environmental-friendly techniques, which will contribute to the harmonization of science, human, and environmental health.

An Overview of Analytical Determination of Diltiazem, Cimetidine, Ranitidine, and Famotidine by UV Spectrophotometry and HPLC Technique

This review article recapitulates the analytical methods for the quantitative determinations of diltiazem and three H2receptor antagonists (cimetidine, ranitidine, and famotidine) by one of the spectroscopic technique (UV spectrophotometery) and separation technique such as high-performance liquid chromatography (HPLC). The clinical and pharmaceutical analysis of these drugs requires effective analytical procedures for quality control, pharmaceutical dosage formulations, and biological fluids. An extensive survey of the literature published in various analytical and pharmaceutical chemistry-related journals has been compiled in its review. A synopsis of reported spectrophotometric and high-performance liquid chromatographic methods for individual drug is integrated. This appraisal illustrates that majority of the HPLC methods reviewed are based on the quantitative analysis of drugs in biological fluids, and they are appropriate for therapeutic drug monitoring purpose.

Raman and IR spectroscopic studies of fenamates--conformational differences in polymorphs of flufenamic acid, mefenamic acid and tolfenamic acid

Solid-state Raman and IR spectra of two polymorphic forms of each of three fenamates (flufenamic acid, mefenamic acid and tolfenamic acid) display subtle but highly reproducible differences. Many of these spectral differences can be ascribed to different conformations of these molecules, involving two of four possible orientations of one substituted benzene ring with respect to the other. Interpretation of the vibrational spectra in terms of conformational differences has been facilitated by DFT calculations at the B3LYP/cc-pVDZ level for each conformer. The calculated spectra are compared with the experimental spectra in order to identify the conformers present in two polymorphic forms in each case, and detailed band assignments are obtained from the DFT calculations.

Infrared studies of the polymorphic states of the fenamates

Infrared spectroscopy has been used to characterize the polymorphic purity as well as to study the thermal conversion of three of the more common fenamates between their different crystalline forms via measuring changes in the NH stretch region that occur between 3300 and 3350 wavenumbers. Shifts in band frequency for mefenamic acid result from differences in internal hydrogen bonding between the NH group and either the carbonyl or hydroxyl groups of the acid moiety. Due to out-of-plane rotations about the central N-C(ring2) bond additional polymorphic states have been suggested for flufenamic and tolfenamic acids. Rates of conversion are given for flufenamic, mefenamic, and tolfenamic acids at temperatures between 85 and 160 degrees C depending on the polymorphic transition for a particular analyte. Subsequently, these rates are used to calculate the activation energy for the observed polymorphic transition. Values of 71.6, 49.0, and 50.8 kcal/mol are obtained respectively for (1) the polymorph I to II transition of mefenamic acid, (2) the polymorph I to II transition of tolfenamic acid, and (3) the polymorph III to I transition of flufenamic acid.

Development and validation of a capillary electrophoresis method for the determination of codeine, diphenhydramine, ephedrine and noscapine in pharmaceuticals

The present work describes a simple, accurate and rapid method for the separation and simultaneous determination of codeine, diphenhydramine, ephedrine and noscapine present in cough-cold syrup formulations by capillary zone electrophoresis. Factors affecting the separation were the buffer pH and concentration, applied voltage, and presence of additives. Separations were carried out in less than 10 min with a 20 mM sodium tetraborate buffer, pH 8.50. The carrier electrolyte gave baseline separation with good resolution, great reproducibility and accuracy. Calibration plots were linear over at least three orders of magnitude of analyte concentrations, the lower limits of detection being within the range 0.42-1.33 microg ml(-1). Detection was performed by UV absorbance at wavelengths of 205 and 250 nm. Quantification of the components in actual syrup formulations was calculated against the responses of freshly prepared external standard solutions. The method was validated and met all analysis requirements of quality assurance and quality control. The procedure was fast and reliable and commercial pharmaceuticals could be analyzed without prior sample clean-up procedure.

Capillary electrophoretic method for determination of protease inhibitor indinavir sulfate used in human immunodeficiency virus therapy

A simple, fast and reliable capillary electrophoresis (CE) method for determination of indinavir sulfate, a potent protease inhibitor used in human immunodeficiency virus (HIV) therapy, in commercial and simulated capsule formulations is described. The analysis was performed in a 75microm i.d. uncoated fused-silica capillary with 27cm length (effective length of 19.4cm) using a 20mmoll-1 phosphate buffer at pH 2.52. Samples were injected hydrodynamically by applying 0.5psi pressure during 2s. The applied voltage was 28kV. Direct UV detection at 214nm led to an adequate sensitivity without interference from sample excipients and known impurities. For quantitative purposes, diazepam was used as internal standard. Under optimized conditions, the migration times for indinavir sulfate and diazepam were 1.06 and 1.66min, respectively. Analytical curve of peak area ratios versus concentration in the range of 20.0-100.0microg/ml gave a coefficient of correlation of 0.9992, establishing the method linearity. The limits of detection and quantitation were 4.61 and 14.0microg/ml, respectively. The within-day precision expressed as relative standard deviation was <1.5% for 10 consecutive sample injections. An average recovery of 100.81+/-0.56% at three concentration levels was obtained. Based on the performance characteristics, the proposed methodology was found suitable for the determination of indinavir sulfate in capsule formulations, presenting additional advantages inherent to the CE technology, such as low consumption of reagents and column endurance.

An overview of the recent trends in development of HPLC methods for determination of impurities in drugs

An extensive survey of the literature published in various analytical and pharmaceutical chemistry related journals has been conducted and the high-performance liquid chromatography (HPLC) methods which were developed and used for determination of process-related impurities in drugs have been reviewed. This review covers the time period from 1995 to 2001 during which around 450 analytical methods including all types of chromatographic and hyphenated techniques were reported. HPLC with UV detection was found to be the technique of choice for many workers and more than 200 methods were developed using LC-UV alone. A critical analysis of the reported data has been carried out and the present state-of-art of HPLC for determination of impurities of analgesic, antibiotic, anti-viral, anti-hypertensive, anti-depressant, gastro-intestinal and anti-neoplastic agents has been discussed.

Simultaneous determination of naphazoline, diphenhydramine and phenylephrine in nasal solutions by capillary electrophoresis

A capillary zone electrophoresis (CZE) method has been developed to separate and quantitate naphazoline (NAPH), dyphenhydramine (DIP) and phenylephrine (PHE) in nasal solutions. Samples were diluted 1:25 in ultrapure water and injected at the anodic end. A central composite design has been used to optimise the experimental conditions for a complete and fast separation of the active ingredients studied. Critical parameters such as voltage, pH and buffer concentration have been studied to evaluate how they affect responses such as resolution and migration times. Separation was performed on a silica capillary with 75 microm I.D. and 70 cm total length at an applied voltage of 17.7 kV with a phosphate run buffer of pH 3.72 and 0.063 mol l(-1). Calibration curves were prepared for NAPH, DIP and PHE. For each analyte, the correlation coefficients were >0.999 (n=15). The RSD% of six replicate injections for each analyte were reasonably good. The method was applied to the quantitation of the three components in a commercial dosage form. The proposed method has the advantage of needing a very simple sample pretreatment and being faster than a typical HPLC chromatographic method.