An Improved Spectrophotometric Method for Determination of Penicillins Alone and in Pharmaceutical Dosage Forms

Abstract

A new spectrophotometric method for determining penicillins has been developed. A known volume of the penicillin solution is heated at 95[ddot]C for 70 min with ammonium molybdate, in sulphuric acid medium and the absorbance of the blue species formed is measured at 670 nm. The method has been successfully applied for the determination of thirteen commercially available penicillins. Beer's law is valid for up to 35-90 μg/ml of antibiotic (according to the penicillin). The procedure has been used for analysing some pharmaceutical preparations for these drugs, e.g., injections and capsules. The sensitivity of the method is largely increased with respect to the vanadate method previously described.     

青霉素类药物的共振光散射光谱分析

本文研究了青霉素钠-碱性品红缔合物的共振散射光谱,建立了pH =7.5的C-L缓冲溶液中,共振光散射法测定青霉素钠的新方法.线性回归方程△IRu=1.74+5.17C,相关系数R=0.9981,检测限3.16×10-7mol/L.该方法简单快速,灵敏度高,对实际样品进行了测定,得到了令人满意的结果.     

Spectrophotometric determination of tetracyclines and cephalosporins with ammonium vanadate

A spectrophotometric method for the determination of some tetracyclines as well as some cephalosporins is described. The drug is boiled with ammonium vanadate solution in sulphuric acid medium for 10 min and the absorbance of the colour developed is measured at 750 nm. The proposed method can be successfully applied to the determination of tetracycline hydrochloride, oxytetracycline hydrochloride, doxycycline hyclate, demeclocycline hydrochloride, chlortetracycline hydrochloride, cephalothin sodium, cephaloridine and cephapirin sodium. These drugs can be determined either in pure form or in pharmaceutical preparations.     

Analytical applications of the photochemical action of light: Determination of oxalic acid by photo-oxidation in the presence of ferric salts

A new method has been developed for the determination of oxalic acid. This depends upon the photochemical oxidation of oxalic acid in. the presence of ferric sulphate. The method involves exposing a measured volume of oxalic acid solution, with an excess of ferric alum and some sulphuric acid,tosunlight in quartz or pyrex beaker for 15 to 30 minutes. The progress of the reaction is indicated by the disappearance of the yellow colour of the ferricoxalate complex from the solution. After completion of the reaction, the ferrous salt formed is determined using standard sodium vanadate and either diphenylbenXXXdine or diphenylamme-sulphonate as internal indicator in the presence of sufficient phosphoric acid. Formic acid does not interfere in the photochemical method of deteminination.     

A new volumetric method for the determination of molybdenum(VI)

Summary A new volumetric method has been developed for the determination of molybdenum(VI). The method consists in the reduction of molybdenum(VI) by heating with a slight excess of hydrazine sulphate in 1 to 2 M hydrochloric acid medium for ten minutes on a water bath. The mixture is cooled and the molybdenum(V) obtained determined by titration with a standard solution of ceric sulphate at an overall acidity of 4 N hydrochloric acid, using diphenyl benzidine as indicator and adding 5 ml of syrupy phosphoric acid for 50 ml of the mixture. Alternately the molybdenum(V) can be titrated with a standard solution of ceric sulphate at an overall acidity of 3 N hydrochloric acid using ferroin as indicator and adding 5 ml of syrupy phosphoric acid for 50 ml of the titration mixture. The molybdenum(V) can also be titrated with a standard solution of sodium vanadate in 8 N sulphuric acid medium, using N-phenyl anthranilic acid as indicator. Alternately, the titration with sodium vanadate can be made with diphenyl benzidine as indicator in 4 N acid medium, adding 5 ml of syrupy phosphoric acid and 1 ml of 1.0 M oxalic acid to catalyse the indicator action. The method now proposed is much more convenient than the methods currently available. It is simple because it does not require any costly chemicals or complicated apparatus. Furthermore, it has the advantages of great rapidity and excellent precision.     

Kinetic fluorimetric determination of traces of vanadium(V) by means of a catalysed autoxidation process

A kinetic method for determination of traces of vanadium(V) (0.04-0.5 ppm) is described. It is based on the catalytic action of vanadate in the autoxidation of sodium 4,8-diamino-1,5-dihydroxyanthraquinone-2,6-disulphonate, giving rise to kinetic curves characterized by an induction period before the appearance of a product exhibiting an intense red fluorescence in acidic solution. This product has been investigated and the experimental variables and interferences have been studied.     

Analytical applications of the photochemical action of light: Determination of ferric iron by photochemical reduction in the presence of citric and mandelic acids

A new method has been developed for the determination of ferric sulphate through its photochemical reduction with citric and mandelic acids in sunlight. The method consists in irradiating with sunlight a measured volume of the ferric sulphate solution together with an excess of citric or mandelic acid in a quartz or pyrex glass beaker until reduction is complete. The ferrous salt formed is determined by titration with a standard solution of sodium vanadate in the presence of the proper concentration of sulphuric and phosphoric acids, employing diphenylbenzidine or diphenylamine sulphonate as internal indicators. The photoreduction is greatly retarded by sulphuric acid.     

Vanadametry Estimation of Thiosulphate

1.(a) We have found that sodium thiosulphate is quantitatively oxidized to tetrathionate in five minutes at room temperature (28°) by excess sodium vanadate in a medium containing sulphuric acid at 0.06N to 0.1N concentration and a little copper sulphate as catalyst. (b) Quantitative emulation of sodium thiosulphate to tetrathionate has also been achieved by the action of excess sodium vanadate during five minutes at room temperature in a medium containing 2.0N—8.0N acetic acid and a little copper salt as catalyst. Further oxidation to sulphate does not occur, even if the mixture is heated to boiling. (c) The excess of unreacted vanadate in 1(a) and 1(b) can be titrated with a standard solution of ferrous ammonium sulphate using diphenylbenzidine as indicator, after adding the requisite quantity of syrupy phosphoric acid. 2. On the other hand, sodium thiosulphate is easily and quantitatively oxidized to sulphate at room temperature, when. acted upon by excess sodium vanadate in a medium containing hydrochloric acid at an overall concentration of 5-6N and 1.0 ml of iodine monochloride as catalyst. The time required for reaction is ten minutes. The unreacted vanadate can be estimated by titration with a standard solution of ferrous ammonium sulphate, using N-phenylanthranilic acid as indicator or with diphenylbenzidine as indicator after suitably diluting and adding phosphoric acid.     

Precipitation of metal-cupferron complexes from homogeneous solution-II: determination of titanium

The cupferron complex of titanium has been precipitated by the addition of phenylhydroxylamine and sodium nitrite to a cold acidic solution of the metal. Details of the method are given. Separation of titanium from aluminium, borate, phosphate and vanadate is described.     

Spectrophotometric determination of vanadium with 1,10-phenanthroline

A simple and sensitive spectrophotometric method for the determination of vanadium based upon the reaction of vanadate with 1,10-phenanthroline in the presence of sodium dithionite in ammoniacal solution is described. The absorbance of the complex measured at 645 nm follows Beer's law for solutions containing 30-400 microg of vanadium in 100 ml of solution. A 10-fold excess of molybdenum, tungsten, phosphorus or chromium does not interfere. The molar absorptivity is 8.0 x 10(3) 1 mole(-1) cm(-1). The complex is shown to be tris-1,10-phenanthroline vanadium(II). The method has been applied successfully to the determination of vanadium in bauxite.     

X-ray powder diffraction patterns for certain beta-lactam, tetracycline and macrolide antibiotic drugs.

X-ray powder diffraction (XRD) data for eight beta-lactam viz., ampicillin sodium, ampicillin trihydrate, penicillin G procaine, benzathine penicillin, benzyl penicillin sodium, cefalexin, cefotaxime sodium and ceftriaxone sodium; three tetracyclines viz., doxycycline hydrochloride, oxytetracycline dihydrate and tetracycline hydrochloride; and two macrolide viz., azithromycin and erythromycin estolate antibiotic drugs were obtained using a powder diffractometer. The drugs were scanned from Bragg angles (2theta) of 10 degrees to 70 degrees. The obtained data were tabulated in terms of the lattice spacing (A) and relative line intensities (I/I(I)). This new information may be useful for identifying these drugs from confiscated materials, which has been frequently encountered in forensic laboratories.     

Determination of iodide with potassium dichromate and sodium vanadate in the presence of acetone

The determination of iodide with potassium dichromate and sodium vanadate in 6-8M phosphoric acid medium by potentiometric or visual titration is described. Ferroin and barium diphenylamine sulphonate (BDAS) are used as the indicators in the visual titration with potassium dichromate and sodium vanadate respectively. Acetone is used to stabilize the iodonium ions liberated, in the visual titration. Iodide can also be determined with sodium vanadate in 2-4M sulphuric acid medium with BDAS as indicator in the presence of oxalic acid as catalyst and acetone to stabilize the liberated iodine cations. The visual procedures are applied for the determination of iodide in tincture of iodine. The formal potentials of the iodine/iodide couple in various phosphoric acid media are reported.     

Studies on residual antibacterials in foods. III. High-performance liquid chromatographic determination of penicillin G in animal tissues using an on-line pre-column concentration and purification system

A simple and reproducible method for the determination of residual penicillin G in edible animal tissues by high-performance liquid chromatography (HPLC) is described. The method consists in an off-line clean-up step using a basic aluminium oxide column and a Sep-Pak C18 cartridge and an on-line pre-column concentration and purification system. The procedure shows good sensitivity and precision. The recoveries from cattle liver, kidney and muscle fortified with 1 microgram/g of sodium penicillin G were 75.0-92.6% and the relative standard deviations were 2.35-4.06%. The detection limit corresponded to 0.05 micrograms/g of sodium penicillin G in animal tissues.     

Flow-injection chemiluminescence determination of penicillin antibiotics in drugs and human urine using luminol-Ag(III) complex system

A chemiluminescent (CL) system based on the reaction of an Ag(III) complex with luminol in alkaline medium is presented. Gamma order of magnitude penicillin species antibiotics could dramatically enhance CL intensities. Coupled with flow injection analysis (FIA), a novel sensitive chemiluminescent analytical technique for some penicillin antibiotics in drugs and urine samples is introduced. Under optimum conditions, benzylpenicillin sodium, amoxicillin, ampicillin and cloxacillin sodium were determinated. Detection limits of this method are 70 ng/mL for benzylpenicillin sodium, 67 ng/mL for amoxicillin, 169 ng/mL for ampicillin and 64 ng/mL for cloxacillin sodium. For the spiked urine samples, the recoveries of the four drugs were in the range of 106–112% for benzylpenicillin sodium, 104–110% for amoxicillin, 104–106% for ampicillin, and 103–105% for cloxacillin sodium. Based on the fluorescence spectra, free radical trapping experiment, and chemiluminescent spectra, a possible reaction mechanism is suggested.     

Detection of Penicillin via Surface Plasmon Resonance Biosensor

A method of using Au colloid to capture the decomposed product of penicillin, penicillamine, on a surface plasmon resonance(SPR) biosensor for the quantitative determination of penicillin was developed. Based on the decomposition of penicillin to generate penicillamine and penilloaldehyde, a high sensitive biosensor for detecting penicillin was also developed. In our experiment, it was penicillamine rather than penicillin that has been measured. This is because penicillamine contains a functional group that makes it self-assembling on Au colloid to increase the molecular weight so as to improve the surface plasmon resonance signal. On a UV-Vis spectrophotometer, a high concentration of penicilliamine-Au complex was determined, indicating that penicillamine was already well combined with Au colloid. The method, using the combination of Au colloid with penicillamine, proved to detect penicillin.     

Determination of thiourea and some of its organic derivatives with sodium vanadate, hexacyanoferrate(III), Cerium(IV) sulphate, manganese(III) and manganese(IV)

The determination of thiourea and some of its organic derivatives with sodium vanadate, hexacyanoferrate(III), cerium(IV) sulphate, manganese(III) and manganese(IV) is described. A mixture of iodate and iodide is used as catalyst. Ferroin, N-phenylanthranilic acid and p-ethoxychrysoidine can be used as indicators.     

Determination of penicillin G in bovine plasma by high-performance liquid chromatography after pre-column derivatization.

A simple, selective, and sensitive liquid chromatographic method with ultraviolet detection was developed for the analysis of penicillin G in bovine plasma. The assay utilizes a simple extraction of penicillin G from plasma (with a known amount of penicillin V added as internal standard) with water, dilute sulphuric acid and sodium tungstate solutions, followed by concentration on a conditioned C18 solid-phase extraction column. After elution with 500 microliters of elution solution, the penicillins are derivatized with 500 microliters of 1,2,4-triazole-mercuric chloride solution at 65 degrees C for 30 min. The penicillin-mercury mercaptide complexes are separated by reversed-phase liquid chromatography on a C18 column. The method, which has a detection limit of 5 ng/ml (ppb) in bovine plasma, was used to quantitatively measure the concentrations of penicillin G in plasma of steers at a series of intervals after the intramuscular administration of a commercial formulation of procaine penicillin G.     

Vanadametry

Summary A vanadametric method has been developed which has definite advantages over iodimetric assay and bromimetric assay for the estimation of isonicotinic acid hydrazide in tablets. The excepients such as lactose, glucose and starch do not interfere in the estimation of the hydrazide with vanadate. Unlike iodimetric and bromimetric assays, the vanadametric assay is rapid.See also Z. analyt. Chem. 160, 117 (1958).     

Volumetric determination of iron (III) with hydroxylamine as a reducing agent

Summary A new volumetric method has now been developed for the determination of iron(III) through reduction to iron(II) with excess of hydroxylamine. The reduction is completed at the temperature of the boiling water bath in 10 min, keeping the acidity at 0.2–0.5 N sulphuric acid. The mixture is cooled and treated with enough 1 1 sulphuric acid to bring up the acidity to 6 N. It is then titrated with a standard solution of sodium vanadate, using N-phenyl anthranilic acid as inside indicator. Diphenyl benzidine, barium diphenyl sulphonate, or 1,10-phenanthroline cannot be used as indicators in this titration, because of the interference of the unreacted hydroxylamine.The method has been found to be very precise, and convenient. It has also the advantage that it is subject to fewer interferences than the existing methods.One of us, Mrs. G. Somidevamma, desires to thank the Ministry of Education Government of India for the award of Research Fellowship which enabled her to take part in this investigation.