Kanakapura Basavaiah

Extractive spectrophotometric determination of some phenothiazine derivatives in pharmaceutical preparations.

A simple, accurate, rapid and sensitive spectrophotometric method has been developed for the assay of six phenothiazine derivatives in bulk drug and their pharmaceutical preparations. The method is based on ion-pair complex reaction of phenothiazines with bromocresol green in aqueous acidic buffer. The chromogen, being extractable with chloroform, could be measured quantitatively at 420 nm. All variables were studied in order to optimize the reaction conditions. The proposed method has been successfully applied to the analysis of the bulk drugs and their dosage forms, tablets and injections. No interference was observed from common pharmaceutical adjuvants. Statistical comparison of the results with those of an official method shows excellent agreement and indicates no significant difference in precision.

Sensitive spectrophotometric determination of amlodipine and felodipine using iron(III) and ferricyanide.

A simple, accurate, sensitive and economical procedure for the estimation of amlodipine besylate and felodipine, both in pure form and in formulations has been developed. The method is based on the reduction of iron(III) by the studied drugs in acid medium and subsequent interaction of iron(II) with ferricyanide to form Prussian blue. The product exhibits absorption maximum at 760 nm in both cases. Beers law is obeyed in the concentration ranges 5.0-15.0 and 1.5-5.0 microg/ml, for amlodipine and felodipine, respectively. The molar absorptivities are 1.76 x 10(4) and 4.24 x 10(4) l/mol cm. The corresponding Sandell sensitivities are 23.18 and 9.06 ng/cm(2). The limits of detection as well as quantification are reported. Seven replicate analyses of solutions containing three different concentrations of each drug were carried out and the percent error and the RSD values have been reported. The proposed method was applied to the determination of these drugs in pharmaceutical formulations and the results demonstrate that the method is equally accurate and precise as the official methods as found from the t- and F-values. The reliability of the method was established by recovery studies using standard-addition technique.

Titrimetric and spectrophotometric assay of some antihistamines through the determination of the chloride of their hydrochlorides

Two simple, rapid and reliable methods for the determination of four antihistamines based on the measurement of the chloride of their hydrochlorides are described. In the titrimetric method, the chloride content of each drug is determined by titrating with mercury(II) nitrate using diphenylcarbazone-bromothymol blue as indicator. In the spectrophotometric method, to a fixed concentration of mercury(II)-diphenylcarbazone complex different amounts of drug are added and the decrease in absorbance of mercury(II)-diphenylcarbazone complex, consequent to the replacement of diphenylcarbazone of the complex by the chloride of the drug, was measured at 540 nm. The stoichiometry of the reaction that forms the basis for titrimetry is assessed. Different variables affecting the color formation in spectrophotometry were studied and optimized. At the wavelength of maximum absorption, Beers law is obeyed in the 0-100 microg ml(-1) range. The molar absorptivity and Sandell sensitivity are calculated. The proposed methods were applied for the analysis of pharmaceutical formulations containing these drugs. Statistical treatment of the experimental results indicates that the procedures are precise and accurate. Excipients used as additives in pharmaceutical formulations did not interfere in the proposed procedures as shown by the recovery studies.

Simple spectrophotometric determination of acyclovir in bulk drug and formulations.

A simple and cost effective spectrophotometric method is described for the determination of acyclovir in bulk drug and in formulations. The method is based on the formation of blue coloured chromogen when the drug reacts with Folin-Ciocalteu (F-C) reagent in alkaline medium. The coloured species has an absorption maximum at 760 nm and obeys Beers law in the concentration range 50-450 microg ml(-1). The absorbance was found to increase linearly with increasing concentration of acyclovir, which is corroborated by the calculated correlation coefficient value of 0.9998 (n = 9). The apparent molar absorptivity and Sandell sensitivity were 1.65 x 10(2) l mol(-1) cm(-1) and 1.36 microg cm(-2), respectively. The slope and intercept of the equation of the regression line are 6.87 x 10(-4) and 8.33 x 10(-3), respectively. The limit of detection was 5.68 microg ml(-1) and the limit of quantification was 18.95 microg ml(-1). The proposed method was successfully applied to the determination of acyclovir in pharmaceutical formulations. The reliability of the assay method was established by parallel determination by standard-addition method, and by recovery studies. The results demonstrated and the procedure is at least as accurate, precise and reproducible (RSD < 2%) as the official method, while being simple and less time consuming. A statistical analysis indicated that there was no significant difference between the results obtained by the proposed procedure and those of the official method.

Application of potassium dichromate and iron-thiocyanate in the spectrophotometric investigations of phenothiazines.

A spectrophotometric procedure for the determination of phenothiazines in pure form and in a number of their pharmaceutical preparations has been developed that offers the advantages of simplicity, accuracy, precision and sensitivity over many other methods. The method is based on the oxidation of phenothiazines by a known excess amount of potassium dichromate followed by the estimation of unreacted amount of dichromate by reacting with excess of iron(II) and measuring the iron(III) formed by complexing with thiocyanate. The reacted oxidant corresponds to the drug content. Different variables affecting the reaction between drugs and dichromate were studied and optimized. At the maximum absorption of 480 nm, Beers law is obeyed in the range 2.5-29.75 microg/ml. The molar absorptivity and Sandell sensitivity of the procedure were calculated in addition to detection limit. Statistical treatment of the experimental results indicates that the procedure is precise and accurate. Excipients used as additives in pharmaceutical formulations did not interfere in the proposed procedure. The reliability of the method was established by parallel determination against the official BP methods. The procedure described was successfully applied to the determination of the bulk drugs and in pharmaceutical formulations.

Gradient HPLC analysis of raloxifene hydrochloride and its application to drug quality control

Gradient HPLC analysis of raloxifene hydrochloride and its application to drug quality control A rapid, sensitive and selective method for the determination of raloxifene hydrochloride (RLX) in pure drug and in tablets was developed using gradient high performance liquid chromatography (HPLC). The devised method involved separation of RLX on a reversed phase Hypersil ODS column and determination with UV detection at 284 nm. The standard curve was linear (R = 0.999) over the concentration range of 50--600 μg mL-1 with a detection limit of 0.04 μg mL-1 and a quantification limit of 0.16 μg mL-1. Intra-day and inter-day precision and accuracy of the method were established according to the current ICH guidelines. Intra-day RSD values at three QC levels (250, 450 and 550 μg mL-1) were 0.2--0.5%, based on the peak area. The intra-day relative error (er) was between 0.2 and 0.5%. The developed method was successfully applied to the determination of RLX in tablets and the results were statistically compared with those obtained by a literature method. Accuracy, evaluated by means of the spike recovery method, was the excellent with percent recovery in the range 97.7--103.2 with precision in the range 1.6--2.2%. No interference was observed from the co-formulated substances. The method was economical in terms of the time taken and the amount of solvent used. Gradijentna HPLC analiza raloksifen hidroklorida i primjena u kontroli kvalitete Koristeći gradijentnu tekućinsku kromatografiju visoke učinkovitosti razvijena je brza, osjetljiva i selektivna metoda za određivanje raloksifen hidroklorida (RLX), čiste supstancije i u tabletama. U radu je primijenjena reverzno-fazna kolona Hypersil ODS te UV detekcija pri 284 nm. Standardna krivulja bila je linearna (R = 0,999) u koncentracijskom području 50--600 μg mL-1. Granica detekcije bila je 0,04 μg mL-1 a granica određivanja 0,16 μg mL-1. Repetabilnost, intermedijalna preciznost i ispravnost ispitivane su prema važećim ICH uputama. Mjerenjem površine ispod pika na tri koncentracijske razine (250, 450 i 550 μg mL-1) procijenjena je repetabilnost na 0,2--0,5%. Relativna pogreška procijenjena unutar jednog dana (er) bila je između 0,2 i 0,5%. Razvijena metoda uspješno je primijenjena za određivanje RLX u tabletama. Rezultati su statistički uspoređeni s rezultatima dobivenim prema ranije objavljenoj metodi. Analitički povrat bio je u rasponu 97,7--103,2 uz preciznost od 1,6 do 2,2%. Nije primijećena interferencija pomoćnih tvari. Metoda je ekonomična s obzirom na utrošeno vrijeme i količine upotrebljenog otapala.

Spectrophotometric determination of ceterizine hydrochloride with Alizarin Red S

A simple, rapid and sensitive spectrophotometric method has been developed for the assay of ceterizine hydrochloride (CTZH) in bulk drug and its pharmaceutical preparations. This method is based on the ion-pair complex reaction between CTZH and Alizarin Red S in Clarks-Lubs buffer. The chromogen being extractable with chloroform, could be measured quantitatively at 440 nm. All variables were studied to optimise the reaction conditions. Regression analysis of Beers Law plot showed good correlation in the concentration range 2.5-22 microg ml(-1). The method has a detection limit of 0.1328 microg ml(-1). The proposed method has been successfully applied for the analysis of the bulk drug and its dosage forms such as tablets and syrups. No interference was observed from common pharmaceutical adjuvants.

Rapid titrimetric and spectrophotometric methods for salbutamol sulphate in pharmaceuticals using N-bromosuccinimide

Rapid titrimetric and spectrophotometric methods for salbutamol sulphate in pharmaceuticals using N-bromosuccinimide One titrimetric and two spectrophotometric methods which are simple, sensitive and rapid are described for the assay of salbutamol sulphate (SBS) in bulk drug and in tablet dosage forms using N-bromosuccinimide (NBS) and two dyes, rhodamine-B and methylene blue, as reagents. In titrimetry, aqueous solution of salbutamol sulphate is treated with a measured excess of NBS in acetic acid medium and after the oxidation of SBS is complete, the unreacted oxidant is determined iodometrically. Spectrophotometric methods entail addition of a known excess of NBS in acid medium followed by the determination of residual oxidant by reacting with a fixed amount of either rhodamine B and measuring the absorbance at 555 nm (method A) or methylene blue and measuring the absorbance at 665 nm (method B). In all methods, the amount of NBS reacting corresponds to the amount of SBS content. Titrimetric method is applicable over 1.74 x 10-4 - 8.68 x 10-4 mol L-1 range and the reaction stoichiometry is found to be 1:6 (SBS:NBS). In spectrophotometric methods, the absorbance is found to increase linearly with the concentration of SBS, which is corroborated by the correlation of coefficients of 0.9993 and 0.9988 for method A and method B, respectively. The systems obey Beers law for 0.25-1.75 μg mL-1 (method A) and 0.5-5.0 μg mL-1 (method B). The calculated apparent molar absorptivity values were found to be 2.10 x 105 and 6.16 x 104 L mol-1 cm-1, for method A and method B, respectively. The limits of detection and quantification are also reported for both spectrophotometric methods. Intraday and inter-day precision and accuracy for the developed methods were evaluated. The methods were successfully applied to the assay of SBS in tablet and capsule formulations and the results were statistically compared with those of a reference method. No interference was observed from common tablet adjuvants. The accuracy and reliability of the methods were further ascertained by recovery experiments via the standard-addition technique.

Titrimetric micro determination of some phenothiazine neuroleptics with potassium hexacyanoferrate(III)

Three simple, rapid and accurate titrimetric procedures using potassium hexacyanoferrate(III) have been developed for the micro determination of five phenothiazine drugs in pure form and in dosage forms. The procedures are based on the oxidation of phenothiazines in an acid medium to colourless sulphoxides via orange or purple coloured products. In the first procedure, phenothiazines are titrated directly in H(2)SO(4)-H(3)PO(4) medium to a colourless end point. In the second method, a known excess of the oxidant is added and after a specified time, the residual oxidant is determined iodometrically. The third method employs electrometric end-point detection. The optimum reactions conditions and other analytical parameters are evaluated. The influence of the substrates commonly employed as excipients with phenothiazine drugs has been studied. Statistical comparison of the results with those of an official method shows excellent agreement and indicates no significant difference in precision.

Simple high-performance liquid chromatographic method for the determination of acyclovir in pharmaceuticals.

An assay method for the determination of acyclovir from pharmaceutical preparations has been developed for assessment of product quality utilising high-performance liquid chromatography. The chromatographic conditions comprised a reversed-phase C18 column (250 x 4.6 mm i.d.) with a mobile phase of acetonitrile-20 mmol l(-1) aqueous ammonium acetate buffer of pH 4.5 (40:60). The flow rate was 0.8 ml min(-1) and UV detection was used at 250 nm. Calibration graph was linear in the range 1.98-59.4 microg ml(-1). The method has been validated according to current guidelines including assay of pharmacopoeial standard tablets. Recoveries ranged from 96.64 to 99.53%. The exipients present in the tablets did not interfere with the method.