Cephradine monohydrate

A simple, selective, and precise densitometric method for analysis of four alpha-aminocephalosporins, namely cefaclor monohydrate, cefadroxil monohydrate, cefalexin anhydrous, and cefradine anhydrous, both in bulk drugs and in formulations was developed and validated. The method employed thin-layer chromatography (TLC) aluminium sheets precoated with silica gel G 60 F(254) as the stationary phase. The solvent system consists of ethyl acetate-methanol-water with different ratios for all studied drugs (R(f) values of 0.40-0.60). The separated spots were visualized as blue to violet color after spraying with ninhydrin reagent. The linear regression analysis data for the calibration plots of all studied drugs produced a good linear relationship with correlation coefficients ranging from 0.9990 to 0.9996 and coefficients of determination ranging from 0.9986 to 0.9992 over the concentration range 2-10 microg/spot. The limits of detection and quantitation for all studied drugs ranged from 0.09 to 0.23 and from 0.27 to 0.84 microg/spot, respectively. The developed method was applied successfully for the determination of the studied drugs in their pharmaceutical dosage forms with good precision and accuracy. Also, the method can be employed as a promising stability-indicating assay.

The solubility of aminocephalosporins in aqueous solution at 37 degrees and an ionic strength of 0.5 exhibited U-shaped curves against pH. At their isoelectric pH, cephradine monohydrate was the most soluble, followed by cephalexin monohydrate and cephaloglycin dihydrate, with intrinsic solubilities of 26.0, 17.2, and 14.8 mg/ml, respectively. The dissolution rate constants from the rotating disk were also determined as a function of the pH of the dissolution medium and interpreted reasonably by the simultaneous dissociation equilibrium reaction and the diffusion kinetics model. Energies for the solubility and dissolution were determined for these three aminocephalosporins.

An accurate, reliable, specific and sensitive kinetic spectrofluorimetric method was developed for the determination of seven cephalosporin antibiotics namely cefotaxime sodium, cephapirin sodium, cephradine dihydrate, cephalexin monohydrate, cefazoline sodium, ceftriaxone sodium and cefuroxime sodium. The method is based on their degradation under an alkaline condition producing fluorescent products. The factors affecting the degradation and the determination were studied and optimized. The reaction is followed spectrofluorimetrically by measuring the rate of change of fluorescence intensity at specified emission wavelength. The initial rate and fixed time methods were used for the construction of calibration graphs to determine the concentration of the studied drugs. The calibration graphs are linear in the concentration ranges 0.2-1.2 microg mL(-1) and 0.2-2.2 microg mL(-1) using the initial rate and fixed time methods, respectively. The results were statistically validated and checked through recovery studies. The method has been successfully applied for the determination of the studied cephalosporins in commercial dosage forms. The high sensitivity of the proposed method allows the determination of investigated cephalosporins in human plasma. The statistical comparisons of the results with the reference methods show an excellent agreement and indicate no significant difference in accuracy and precision.

Wastewater treatment plants (WWTPs) are regarded as one of the most important sources of antibiotics in the environment. The occurrence, seasonal variation and removal efficiency of 21 antibiotics and 10 metabolites, including five sulfonamides and three of their metabolites, six quinolones, two macrolides, two β-Lactams and five tetracyclines and seven of their metabolites, were investigated in five WWTPs in different seasons in the Jiulongjiang River Region, South China. 16 antibiotics and 6 metabolites in summer and 14 antibiotics and 6 metabolites in winter were found, respectively. The most frequently detected antibiotics were sulfamethazine, sulfamethoxazole, n-acetyl sulfamethazine, n-acetyl sulfamethoxazole, ofloxacin, cephalexin monohydrate and cephradine; of these, the concentration of cephradine was the highest in most of the influent and effluent samples. The highest level of total antibiotics was found in Longyan City WWTPs, where there are more population and swine farms. Seasonal variation of the antibiotics in wastewater samples was also studied. The concentrations of antibiotics in winter were higher than those in summer. The antibiotics could not be removed completely by the WWTPs, and the mean removal efficiency ranged from -71.6 to 56.3%. Of all the antibiotics, the tetracyclines were removed comparatively more efficiently, probably due to their adsorption to sludge. The low removal efficiency of antibiotics in WWTPs could be one of the important reasons for the presence of antibiotics in the environment in Jiulongjiang Region.

Clinical pharmacology of 3-(5-methyl-1,3,4-thiadiazol-2-ylthiomethyl)-8-oxo-7-(tetrazol-1-ylacetamido)-5-thia-1-azabicyclo-(4,2,0)oct-2-en-carbonic acid (cefazolin) and D-7-[2-amino-(cyclohexa-1,4-dien-1-yl)-acetamido]-3-methyl-8-oxo-5-thia-1-aza-(4,2,0)-oct-2-ene-2-carbonic acid monohydrate (cefradine) was compared in young and old adults without renal disease after i.v. injection of 1 g. Mean serum levels of cefazolin after 4 h and 6 h were significantly higher in old persons (25.0 and 14.7 mug/ml, resp.) than in young persons (16.2 and 7.8 mug/ml, resp.). Serum concentrations of cefradine after 2 and 4 h were found also higher in the aged (11.2 and 4.4 mug/ml, resp.) than in young adults. Half-life of cefazolin was prolonged from normally 94 min to 189 min, half-life of cefradine from 32 min to 72 min. Skin blister fluid punctured once for antibiotic assay contained less cefazolin in old persons (after 4 and 6 h only 22.4 and 17.4 mug/ml, resp.) than in young persons (32.7 and 27.6 mug/ml, resp.). Cefradine levels in skin blister fluid 0.5 and 1 h after i.v. injection showed also a significant difference (11.4 and 11.9 mug/ml, resp.) in old persons, 17.3 and 16.5 mug/ml, resp., in young persons). Elimination constants (alpha, beta, kel, k12, k21) were always lower in geriatric patients. Renal clearance of cefazolin was reduced from 83 ml/min to 43 ml/min, and renal clearance of cefradine from 378 ml/min to 152 ml/min. After i.v. injection of 1 g 6-sulfanilamido-2,4-dimethyl-pyrimidine (sulfisomidine) total content of the drug in blood was higher in elderly people than in young persons, but proportion of acetylated sulfisomidine was nearly the same in both groups (15%). It is supposed that higher serum levels of some drugs in old persons (over 70 years) can be explained by impaired renal excretion and slower tissue penetration of the compound from the blood.

A simple, reliable, and sensitive kinetic spectrophotometric method was developed for determination of eight cephalosporin antibiotics, namely, Cefotaxime sodium, Cephapirin sodium, Cephradine dihydrate, Cephalexin monohydrate, Ceftazidime pentahydrate, Cefazoline sodium, Ceftriaxone sodium, and Cefuroxime sodium. The method depends on oxidation of each of studied drugs with alkaline potassium permanganate. The reaction is followed spectrophotometrically by measuring the rate of change of absorbance at 610 nm. The initial rate and fixed time (at 3 minutes) methods are utilized for construction of calibration graphs to determine the concentration of the studied drugs. The calibration graphs are linear in the concentration ranges 5-15 mug mL(-1) and 5-25 mug mL(-1) using the initial rate and fixed time methods, respectively. The results are validated statistically and checked through recovery studies. The method has been successfully applied for the determination of the studied cephalosporins in commercial dosage forms. Statistical comparisons of the results with the reference methods show the excellent agreement and indicate no significant difference in accuracy and precision.