A Selective Spectrofluorimetric Method for the Determination of Some α-Aminocephalosporins in Formulations and Biological Fluids

New spectrofluorimetric method for determination of cephalosporins in pharmaceutical formulations

A simple, accurate, precise spectrofluorimetric method has been proposed for the determination of three cephalosporins, namely, cefixime (cefi), cephalexine (ceph), and cefotaxime sodium (cefo) in pharmaceutical formulations. This method is based on a reaction between cephalosporins with 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt (HPTS) in alkaline medium, at pH 12.0 for cefi and 13.0 for ceph and cefo to give highly fluorescent derivatives extracted with chloroform and subsequent measurements of the formed fluorescent products at 520, 500 and 510 nm after excitation at 480, 470 and 480 nm for cefi, ceph and cefo respectively. The optimum experimental conditions have been studied. Beer's law is obeyed over concentrations of 10-60 ng/mL, 5-35 ng/mL and 10-60 ng/mL for cefi, ceph and cefo, respectively. The detection limits were 4.20 ng/mL, 2.54 ng/mL and 4.09 ng/mL for cefi, ceph and cefo, respectively, with a linear regression correlation coefficient of 0.99783, 0.99705 and 0.9978 and recoveries in ranges 96.96-105.77, 96.13-102.55 and 95.45-105.39% for cefi, ceph and cefo, respectively. This method is simple and can be applied for the determination of cefi, ceph and cefo in pharmaceutical formulations in quality control laboratories.

Kinetic spectrophotometric determination of certain cephalosporins in pharmaceutical formulations

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.

Analysis of cephalosporin antibiotics

A comprehensive review with 276 references for the analysis of members of an important class of drugs, cephalosporin antibiotics, is presented. The review covers most of the methods described for the analysis of these drugs in pure forms, in different pharmaceutical dosage forms and in biological fluids.

Colourimetric and AAS determination of cephalosporins using Reineck's salt

Two simple, accurate, sensitive and selective procedures for the determination of eight cephalosporins are described. These procedures are based on the formation of ion-pair complexes between the drugs and ammonium reineckate, the formed precipitates are quantitatively determined either colourimetrically or by atomic absorption spectrometrically. The methods consist of reacting drugs with Reinecke's salt in an acidic medium at 25+/-2 degrees. The first colourimetric procedure (procedure I) is based on dissolving the formed precipitate with acetone, the volume was completed quantitatively and the absorbance of the solution was measured at 525 nm against pure solvent blank. Also, the formed precipitates on the atomic absorption spectrometric procedure (procedure II) are quantitatively determined directly or indirectly through the chromium precipitate formed or the residual unreacted chromium in the filtrate at 358.6 nm. The optimum conditions for precipitation have been carefully studied. Beer's law is obeyed for the studied drugs in the range 5-35 microg ml(-1) with correlation coefficients not less-than 0.9989. Both procedures I and II hold well accuracy and precision when applied to the analysis of the cited cephalosporins in different dosage forms with good recovery percent ranged from 98.7+/-0.90 to 100.1+/-0.74 without interference from additives.

Selective spectrophotometric determination of phenolic beta-lactam antibiotics

Two simple and selective spectrophotometric methods were developed for the quantitative determination of cefoperazone sodium, cefadroxil monohydrate, cefprozil anhydrous and amoxicillin trihydrate in pure forms as well as in their pharmaceutical formulations. The methods are based on the selective oxidation of these drugs with either Ce (IV) or Fe (III) in acid medium to give an intense yellow coloured product (lambda(max)=397 nm). The reaction conditions were studied and optimized. Beer's plots were obeyed in a general concentration range of 5-30 microg ml(-1) with correlation coefficients not less than 0.9979 for the four drugs with the two reagents. The methods are successfully applied to the analysis of pharmaceutical formulations containing amoxicillin, either alone or in combination with potassium clavulanate, flucloxacillin or dicloxacillin. They were also applied to the analysis of the other three studied drugs in vials, capsules, tablets and suspensions with good recovery; percent ranged from 99.7 (+/-0.46) to 100.32 (+/-1.05) in the Ce (IV) method and 99.6 (+/-0.50) to 100.3 (+/-1.32) in the Fe (III) method. Interferences from other antibiotics and additives products were investigated.

Spectrofluorometric determination of alpha-aminocephalosporins in biological fluids and pharmaceutical preparations

A selective and highly sensitive fluorometric method was developed for the determination of four alpha-aminocephalosporins, namely cefaclor, cefadroxil, cephalexin and cephradine. The method involves the reaction of the target compounds with fluorescamine at a specific pH, ranging from 7.8 to 8.4. The produced derivatives exhibit maximum fluorescence intensities at 472-478 nm after excitation at 370-372 nm. The method is highly specific because other alpha-aminocephalosporins whose alpha amino group was blocked do not react similarly and hence do not interfere. At the specific pH range of the reaction where no degradation may occur with that medium the proposed method can be utilised as a stability-indicating assay. The different experimental parameters affecting the derivatisation reaction were carefully studied and incorporated into the procedure. Under the described conditions, the proposed method is linear over the concentration range of 0.05(-1) microg/ml(-1) for both cefaclor and cephalexin, and 0.05-0.65 and 0.025-0.5 microg/ml(-1) for cefadroxil and cepharadine, respectively and the coefficients of determination were greater than 0.999 (n = 3). The recoveries of the title compounds from spiked serum ranged from 88.6 to 89.7% and from spiked urine from 92.2 to 93.3% with a limit of quantitation (LOQ) of 25-50 ng/ml(-1) and limit of detection (LOD) of 5 ng/ml(-1) (S/N = 2) for all drugs. The mechanism of the fluorometric reaction is proposed and the advantages of the proposed method are discussed.

Indirect polarographic and cathodic stripping voltammetric determination of cefaclor as an alkaline degradation product

Cefaclor is not reducible at a mercury electrode, but it can be determined polarographically and by cathodic stripping voltammetry as its initial alkaline degradation product which is obtained in high yield by hydrolysis of cefaclor in Britton-Robinson (B-R) buffer pH 10 at 50 degrees C for 30 min (reduction peak at pH 10, -0.70 V). Differential pulse polarographic calibration graphs are linear up to at least 1 x 10(-4) mol/l(-1). Recoveries of 93% of the cefaclor (n = 3) were obtained from urine spiked with 38.6 microg/ml(-1) using this polarographic method with 1 ml urine made up to 10 ml with pH 10 buffer. Using cathodic stripping voltammetry and accumulating at a hanging mercury drop electrode at - 0.2 V for 30 s, linear calibration graphs were obtained from 0.35 to 40 microg/ml(-1) cefaclor in B-R buffer pH 10. A relative standard deviation of 4.2% (eta = 5) was obtained, and the limit of detection was calculated to be 2.9 ng/ml(-1). Direct determination of cefaclor in human urine (1 ml of urine was made up to 10 ml with pH 10 buffer) spiked to 0.39 microg/ml(-1) was made (recovery 98.6%).