Drugs In Pure Forms Research Articles

Spectrophotometric Analysis of Selective Serotonin Reuptake Inhibitors Based on Formation of Charge-Transfer Complexes with Tetracyanoquinodimethane and Chloranilic Acid

A simple, accurate, and sensitive spectrophotometric method for analysis of selective serotonin reuptake inhibitors (SSRIs) has been developed and validated. The analysis was based on the formation of colored charge-transfer complexes between the intact molecule of SSRI drug as an n-electron donor and each of tetracyanoquinodimethane (TCNQ) or p-chloranilic acid (pCA) as electron acceptors. The formed complexes were measured spectrophotometrically at 842 and 520 nm for TCNQ and pCA, respectively. Different variables and parameters affecting the reactions were studied and optimized. Under the optimum reaction conditions, linear relationships with good correlation coefficients (0.9975-0.9996) were found between the absorbances and the concentrations of the investigated drugs in the concentration ranges of 4-50 and 20-400 microg/mL with TCNQ and pCA, respectively. With all the investigated drugs, TCNQ gave more sensitive assays than pCA; the limits of assay detection were 2.5-4.8 and 20-40 microg/mL with TCNQ and pCA, respectively. The intra- and interassay precisions were satisfactory; the relative standard deviations did not exceed 2%. The proposed procedures were successfully applied to the analysis of the studied drugs in pure form and pharmaceutical formulations with good accuracy; the recovery values were 98.4-102.8 +/- 1.24-1.81%. The results obtained from the proposed method were statistically comparable with those obtained from the previously reported methods.

CHEMOMETRICS ASSISTED SPECTROPHOTOMETRIC METHOD FOR SIMULTANEOUS DETERMINATION OF CERTAIN FLUOROQUINOLONES AND THEIR DECARBOXYLATED DEGRADANTS

Simple multivariate spectrophotometric procedure for simultaneous determination of levofloxacin and norfloxacin as representative examples of fluoroquinolones and their decarboxylated degradation products is described. The method is based on the spectrophotometric measurements of the studied drugs and their degradants in 0.1 M hydrochloric acid solutions in the general range of 200-370 nm together with multivariate calibration analysis. The components of mixtures composed of either levofloxacin or norfloxacin and the corresponding degradant. show a considerable degree of spectral overlapping (85.1-87.4%). Resolution of the binary mixtures under investigation has been accomplished mainly by using classical least squares (CLS) analysis. The method is applied successfully for determination of each drug in pure form, laboratory prepared degraded samples and in expired commercial dosage forms and good recoveries were obtained. Results were compared to those obtained by reported procedures for the same combinations and the required statistical parameters were calculated. The degradation rates for the studied drugs at 150° in 2 M HCl were also studied using the proposed procedure. The calculated first order rate constants for the decarboxylation of the studied drugs were found 0.109 and 0.082 hour-1 and the t1/2 were 6.32 and 8.50 hours for levofloxacin and norfloxacin respectively

A validated spectrofluorimetric method for determination of some psychoactive drugs

Five psychoactive drugs namely, chlorpromazine HCl, thioridazine HCl, clomipramine HCl, imipramine HCl and desipramine HCl were analyzed by a simple spectrofluorimetric method. The method is based on oxidation of the studied drugs using cerium(IV) in presence of sulphuric acid and monitoring the fluorescence of the formed cerium(III) at λ ex. = 254 nm and λ em. = 355 nm. All variables affecting the reaction conditions such as; cerium(IV) concentration, sulphuric acid concentration, heating time, temperature and dilution solvents were carefully studied. The effect of potential interference due to common ingredients as glucose, sucrose, lactose, citric acid and propylene glycol were investigated. A validation study of the proposed method was carried out according to USP 2002. Beer's law was obeyed for all the studied drugs in the concentration range of 0.05–1.3 μg/ml. Limits of detection range was 0.035–0.038 μg/ml and limits of quantitation of 0.116–0.125 μg/ml were obtained. The method was successfully applied for the assay of the studied drugs in pure form and in pharmaceutical dosage forms. Results were compared with official methods. The t- and F-values were calculated and compared with the theoretical values, which indicate high accuracy and good precision of the proposed method.

Extractive Spectrophotometric Methods for the Determination of Oxomemazine Hydrochloride in Bulk and Pharmaceutical Formulations Using Bromocresol Green, Bromocresol Purple and Bromophenol Blue

Three simple, sensitive and accurate spectrophotometric methods have been developed for the determination of oxomemazine hydrochloride in bulk and pharmaceutical formulations. These methods are based on the formation of yellow ion-pair complexes between the examined drug and bromocresol green (BCG), bromocresol purple (BCP), and bromophenol blue (BPB) as sulphophthalein dyes in acetate-HCl buffer of pH 3.6, 3.4, and 4.0, respectively. The formed complexes were extracted with dichloromethane and measured at 405 nm for all three systems. The best conditions of the reactions were studied and optimized. Beer's law was obeyed in the concentration ranges 2.0-12, 2.0-13, and 2.0-14 microg mL(-1) with molar absorptivities of 3.2 x 10(4), 3.7 x 10(4), and 3.1 x 10(4) L mol(-1) cm(-1) for the BCG, BCP, and BPB methods, respectively. Sandell's sensitivity, correlation coefficient, detection and quantification limits are also calculated. The proposed methods have been applied successfully for the analysis of the drug in pure form and in its dosage forms. No interference was observed from common pharmaceutical excipients. Statistical comparison of the results with those obtained by HPLC method shows excellent agreement and indicates no significant difference in accuracy and precision.

Spectrophotometric Determination of Aciclovir, Cefepirne Hydrochloride, Etamsylate and Metoclopramide Hydrochloride Usina 1,10 Phenanttrroline—Fe(lll) Reaqent

A simple, rapid, sensitive and accurate method for the determination of aciclovir, cefepime HCI, etamsylate and metoclopramide HCI in pure form and in pharmaceutical formulations is developed.The method is based on the fomabon of tris(o-phenanthroline) iron(ll) complex (Ferroin) upon the reaction of the ated drugs wrth iron(lll )-o- phenanthroline mixture. The ferroin complex is colorimetncally measured at λmax 510 nm against a reagent blank. 0ptimization of the experimental conditions is described. Beer's law is obeyed in the concentration range from 0.25–30 µg ml−1 with molar absorpitivities (ε) ranging from 4.796 x 103–9.51 2 x 104 L.mol−1.cm−1 and Sandell sensitivities (S) of 2.129 x 10−3–34.5 x 10−3 µg cm−2. The developed method is applied successfully for the determination of the cited drugs in pure forms and in the corresponding pharmaceutical formulations without any interferences from common excipients.

Spectrophotometric Determination of Ampicillin, Amoxycillin, and Carbenicillin Using Folin-Ciocalteu Phenol Reagent

A spectrophotometric method for the determination of penicillins (ampicillin, amoxycillin and carbenicillin) using Folin-Ciocalteu reagent (FC reagent) is described. The reaction mixture of penicillin and FC reagent (pH ∼ 2.25) was heated in a thermostated water bath (95 ± 2°C) and the resulting blue color due to the formation of heteropoly blues was detected spectrophotometrically at the corresponding λmax for these penicillins. The experimental conditions were optimized and Beer's law was obeyed over the applicable concentration ranges. The precision of the proposed method was checked using 10 replicate determinations of a specified amount of these penicillins. The proposed method was applied successfully for the analysis of these drugs in pure form and pharmaceutical preparations. The results obtained from the proposed and reference methods were compared statistically using the Student's t and F-variance ratio tests. A statistical analysis of the results is reported.

Study of Reactions of Triiodide and Alizarin Red S with Some Important Phenothiazines. Development of an Indirect Titrimetric and a Spectrophotometric Method for the Assay of Phenothiazine Derivatives

AbstractThe reactions of a triiodide ion and alizarin red S with some N‐substituted phenothiazine drugs have been studied for the development of two simple, rapid, sensitive and accurate indirect titrimetric and extractive‐spectrophotometric methods for determining these drugs. Spectroscopic studies and chemical analysis showed that the protonated forms of phenthiazines, (PhenH2)2+, react with triiodide ions forming highly stable and insoluble ion pair products as (PhenH2)(I3)2. Formation of ion association complexes have been applied to the development of an indirect visual titrimetric method for the determination of chlorpromazine hydrochloride (CPH), trifluoperazine hydrochloride (TFPH), fluphenazine hydrocholoride (FPH) and promethazine hydrochloride (PMH) over the range 10−5–10−2 M. The extractional‐spectrophotometric method is based on the formation of (1:1) ion‐association complexes between drugs and alizarin red S as chromogenic reagents in acidic citrate buffer that are extractable into chloroform with an absorption maximum at 425 nm. The effect of different factors such as organic solvents, pH, and reagents concentration, were studied. CPH, TFPH and FPH can be determined over the range 9–57, 14–77 and 7–71 ppm, respectively. The proposed methods were applied for the analysis of the studied drugs in pure forms and their commercial preparations. Results are in good agreement with those obtained by official methods.

Spectrophotometric and potentiometric determination of piroxicam and tenoxicam in pharmaceutical preparations.

Two simple and accurate methods are described for the determination of piroxicam and tenoxicam in their pharmaceutical preparations. The spectrophotometric method involves the oxidation of these drugs with potassium iodate in acid medium with the liberation of iodine and subsequent extraction with cyclohexane followed by measuring the absorbance at lambda=522 nm. Beer's law is obeyed in the concentration range of 0.05-1.1 and 0.05-0.6 mg x ml(-1) for piroxicam and tenoxicam, respectively. The apparent molar absorptivities of the resulting coloured products are found to be 2.7 x 10(3) and 2.5 x 10(3) l mol(-1) x cm(-1), whereas Sandell sensitivities are 0.012 and 0.013 g x cm(-2) for piroxicam and tenoxicam, respectively. The potentiometric method involves the direct titration of both drugs with N-bromosuccinimide in acid medium and the end point is determined potentiometrically using platinum indicator electrode. Piroxicam and tenoxicam can be determined quantitatively in the concentration range of 0.33-3.37 and 0.33-4.08 mg x ml(-1) for tenoxicam and piroxicam, respectively. The standard deviation and relative standard deviation values are found to be ranged from 0.05-0.07 and 0.37-0.98% and 0.025-0.078 and 0.25-1.2% for tenoxicam and piroxicam, respectively. The two methods are accurate within +/-1.0%. Optimum conditions affecting both methods are studied. The proposed methods are applied for the determination of the drugs in pure form and in commercial pharmaceutical preparations.

Triiodide ion and alizarin red S as two new reagents for the determination of clotrimazole and ketoconazole

The reactions of a triiodide ion and alizarin red S with two important antifungal drugs containing an imidazole ring (ketoconazole (KC) and clotrimazole (CT)) have been studied for the development of two simple, rapid, sensitive and accurate indirect titrimetric and extractive-spectrophotometric methods for determining the concentration of these drugs. Spectroscopic studies and chemical analysis showed that the protonated forms of KC and CT react with triiodide ion forming highly stable and insoluble ion-pair products such as (KCH 2)(I 3) 2 and (CTH)I 3. Formation of ion-association complexes have been applied to the development of an indirect visual titrimetric method for the determination of KC and CT over the range 10 −5–10 −2 M. The extractive-spectrophotometric method is based on the formation of (1:1) ion-association complexes between drugs and alizarin red S as chromogenic reagent in acidic citrate buffer that are extractable into chloroform with an absorption maximum at 425 nm. The system obeyed Beer's law in the concentration range 2.5–50 and 2.7–80 μg ml −1 for CT and KC, respectively. The proposed methods were applied for the analysis of the studied drugs in pure forms and their commercial preparations. Results are in good agreement with those obtained by official methods.

Simultaneous Determination of Promethazine, Chlorpromazine, and Perphenazine by Multivariate Calibration Methods and Derivative Spectrophotometry

Partial least-squares (PLS) regression, singular value decomposition-based PLS, and an artificial neural network (ANN) were tested as calibration procedures for the simultaneous determination of promethazine, chlorpromazine, and perphenazine by both conventional and derivative spectrophotometry. Comparison of the results revealed that the application of the ANN to the derivative spectra is superior to the application of the 2 PLS methods used. Different binary and ternary synthetic mixtures of the phenothiazine drugs in pure form and in tablets were analyzed by the proposed method, and acceptable results were obtained.

A highly sensitive spectrophotometric method for the determination of some phenothiazine antipsychotics using chloramine-T and indigocarmine.

A new simple, accurate and precise spectrophotometric method for the determination of six phenothiazine drugs in pure form and in dosage forms is described. The method is based on the oxidation of the studied drugs by a known excess of Chloramine-T in hydrochloric acid medium and subsequent determination of the unreacted oxidant by reacting it with indigocarmine in the same acid medium. The reacted oxidant corresponds to the drug content. The colored species exhibits maximum absorption at 610 nm. The apparent molar absorptivity values and Sandell sensitivity values are in the range 1.53 x 10(4)-2.96 x 10(4) l mol-1 cm-1 and 13.75-37.15 ng cm-2, respectively. The method is highly sensitive and suitable for 1-15 micrograms ml-1 concentrations with the detection limits being in the range, 0.0651-0.1724 microgram ml-1. The method was successfully applied to the studied drugs in their dosage forms. The results are reproducible within +/- 1% and compare favorably with those obtained by the procedures of the British Pharmacopeia.

SPECTROPHOTOMETRIC DETERMINATION OF SOME PHARMACEUTICAL COMPOUNDS USING 2,2-DIPHENYL-1-PICRYLHYDRAZYL

A simple, rapid and sensitive spectrophotometric procedure for the assay of some drugs has been developed. The method is based on the reaction of the studied drugs with 2,2-diphenyl-1-picrylhydrazyl (DPPH). The latter is employed to abstract a hydrogen atom from the drugs thereby promoting a process of radical coupling. This results in a reduction of the violet color of DPPH with the formation of the yellow colored 2,2-diphenyl-1-picrylhydrazine (DPPH2). The decrease in the intensity of the violet color is used to measure the concentration of the drugs. All measurements are made at λ= 520 nm on methanolic solutions of the reagent and drugs. Beer's law is obeyed in the ranges of 5-30 µg/ml (for aceclofenac, diclofenac sodium and thiaprofenic acid), 2-15 µg/ml (for tenoxicam, furosemide and lansoprazole) and 2-12 µg/ml (for benoxinate hydrochloride and ritodrine). The validity of the method was tested by carrying out standard addition procedure analyzing the studied drugs in pure form as well as in their pharmaceutical preparations without interference from common additives. Results of the proposed methods are in good agreement with those of the official or reported methods.

Spectrophotometric determination of loperamide hydrochloride by acid-dye and charge-transfer complexation methods in the presence of its degradation products

Two simple, sensitive and accurate spectrophotometric methods for the determination of loperamide hydrochloride (lop. HCl) are described. The first method is based on the formation of ion-pair association complex (1:1) with bromothymol blue (BTB), bromophenol blue (BPB) and naphthol blue black B (NBB). The coloured products are extracted into chloroform, and measured spectrophotometrically at 414 (BTB), 415 (BPB) and 627 nm (NBB). Beer’s law was obeyed in the ranges of 5–35, 5–30 and 0.8–11.2 μg ml −1 for BTB, BPB and NBB methods, respectively. The method was found to be specific for the analysis of the drug in presence of its degradation products which can be detected by HPLC procedure. The second method is based on the reaction of the basic loperamide with iodine in chloroform to give molecular charge-transfer complex with intense bands at 295 and 363 nm. Beer’s law was obeyed in the ranges 2.5–17.5 and 2.5–22.5 μg ml −1 for the method at 295 and 363 nm, respectively. Optimization of the different experimental conditions are described for both methods. The proposed methods have been applied successfully for the analysis of the drug in pure form and in its dosage forms. The methods have the advantage of being highly sensitive and simple for the determination of a small dose drug, which is also a weak UV-absorbing compound.

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 2SO 4–H 3PO 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.

Spectrophotometric Assay of Some Antipsychotropic and Anticholinergic Phenothiazine Drugs Using Ammonium Molybdate

A simple, rapid and sensitive spectrophotometric method has been described for the quantitative determination of six phenothiazine-based antipsychotropic and anticholinergic drugs in pure form as well as in formulations. The method is based on the formation of stable phenothiazonium free radical cation by the use of ammonium molybdate as chromogenic agent. The drugs in 3.0 to 5.0M H2SO4 medium when heated in a boiling water bath react with molybdate to give intense orange or purple or blue products which possess characteristic absorption maxima at 500–638 nm. Beer's law is obeyed over the concentration range 1–60 μg.ml−1 with apparent molar absorptivities ranging from 4.37x103-9.61 × 103 l. mol−1. The proposed method has been applied successfully for the determination of examined drugs both in pure form and representative pharmaceutical formulations. The accuracy and precision of the assay method are comparable with those of the official method.

Enthalpimetric Determination of Sulfa Drugs in Pure Form and Pharmaceutical Formulations

A thermal analysis method has been developed for the micro-determination of sulfa compounds and trimethoprim (TMP) in pure form and in pharmaceutical formulations. The amounts of heat absorbed by different weights of pure compounds have been determined by differential scanning calorimetry (DSC) and applied for construction of a calibration curve for each compound. The linear plot indicates quantitative response. The lines pass through the origin and have high correlation coefficients (0.97-0.99). The accuracy of the method is indicated by the excellent percentage recovery (100+0.1- 4.2% error), and the precision is supported by the low relative standard deviation value <0.03. The method is highly satisfactory for the mg range of the pure compounds. The method was extended to synthetic mixtures of trimethoprim (TMP) and sulfamethoxazole (SMx) in different proportions and analysis of pharmaceutical preparations. When TMP was present in low proportions (<25%), the standard addition method was used.

SPECTROPHOTOMETRIC DETERMINATION OF SOME CEPHALOSPORINS USING 2,2'-DIPHENYL-1-PICRYLHYDRAZYL

A spectrophotometric method was developed for the determination of some cephalosporins using 2,2'-diphenyl-1-picrylhydrazyl (DPPH). The latter employed to abstract a hydrogen atom from the drug thereby promoting a process of radical coupling. This results in a reduction of the violet color (520 nm) of DPPH with the formation of the yellow colored 2,2'-diphenyl-1-picrylhydrazine (DPPH). This fading in color of DPPH reagent depends on the concentration of the drug being determined. Beer's law was obeyed in the ranges of; 5-30, 5-25 and 10-30 µg/ml for cephalexin, cefadroxil and cephradine respectively. The validity of the method was tested by carrying out standard addition procedure analyzing the studied drugs in pure form as well as in their pharmaceutical preparations without interference from common additives. The percentage recovery ranged from (97.98-101.21) ±1.15-0.98.

Spectrophotometric Determination of Some Pharmaceutical Compounds Using 2,2-Diphenyl-1-picrylhydrazyl

Abstract A spectrophotometric method for the determination of some pharmaceutical amides, hydrazides and thiols is described. The method is based on the reaction of the studied drugs with 2,2-diphenyl-1-picryl hydrazyl (DPPH). The latter is employed to abstract a hydrogen atom from the drugs thereby promoting a process of radical coupling. This results in a reduction of the violet colour of DPPH with the formation of the yellow coloured 2,2-diphenyl-1-picrylhydrazine (DPPH2). This fading in colour of DPPH reagent depends on the concentration of the drug being determined. Beer's law is obeyed in the ranges of 1–5 μg/ml (for isocarboxazid and gliclazide), 0.25–2.5 μg/ml (for isoniazid), 0.5–5 μg/ml (for iproniazid), 1–7 μg/ml (for tolazamide), 2–15 μg/ml (for captopril) and 1–6 μg/ml (for sulphathiourea). The validity of the method was tested by analysing the studied drugs in pure form as well as in tablets. Results of analyses were compared statistically with the official or reported methods.

Early cirrhosis of the liver produced in dogs by carbon tetrachloride.

In studying the toxicity of carbon tetrachloride it was found that this drug in pure form causes very severe central necrosis of the liver which heals with scar formation., The toxicity of a large dose of carbon tetrachloride (4 cc. per kilo) is greatly increased by the addition of alcohol. Experiments were carried out to determine the effect of repeated doses of carbon tetrachloride alone and carbon tetrachloride given with alcohol in order to study the toxicity of such repeated doses and the effect on the liver. Ten dogs were used; some were given the therapeutic dose of carbon tetrachloride (3 cc), others 4 cc. per kilo, and others the same doses of carbon tetrachloride but with the addition of approximately 25 cc. of 50 per cent alcohol, and finally a control series was given the same dose of alcohol alone. The dogs were given these doses of the drug over a period of approximately sixteen weeks. No signs of intoxication in any of the dogs were seen. They maintained or gained weight and were killed for autopsy in apparently perfect condition. (One or two dogs died from unknown causes within the first day or two.) The livers of the dogs receiving alcohol showed nothing macro-scopically or microscopically. All the other dogs showed definite signs of an early cirrhosis of the liver. Macroscopically the liver showed a uniformly granular scarred surface in which there were numerous larger nodules and hyperplastic hepatic cells. Microscopically there was extensive scarring of the liver and distortion of lobulation by fibrous tissue. There was also abundant cellular infiltration and some regeneration of bile ducts. There was no apparent difference in the livers of the dogs receiving carbon tetrachloride alone or both carbon tetrachloride and alcohol.