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This chapter is a part of the book “Recent advances in biometrics” introduces the importance of biometrics in the aquatic studies in brief view. Biometric measurements (Morphometric, meristics and description) are widely used in various fields’ “taxonomy, species identifications, monitoring of pollution, species abnormalities, comparison, environmental changes, growth variation, feeding behavior, ecological strategies, stock management, and water quality of aquaculture. These data were collected from several articles and books of aquatic animals and presented both applications and required considerations for biometric implementations. It is important also to detect sexual dimorphism, adaptations during evolutionary time and diminishing intraspecific competition by increasing niche portioning. The biometrics could be applied for various aquatic organisms as dolphins, sharks, rays, mollusca, crustaceans, protozoa, … etc. and for specific organs like teeth, otolith and appendages by different techniques and preservations. Scientists are still applying these measurements even with the presence of advanced techniques like PCR as they are low in cost, faster and more applicable. This chapter also presented some recent trends including animal’s biometric recognition systems, followed by challenges and considerations for the biometrics implementations. It is recommended to apply biometrics in wide range together with modern techniques considering the specificity of its quality and preservation status.

This work describes five simple and reliable spectrophotometric and chromatographic methods for analysis of hepatitis C antiviral binary mixture of ledipasvir (LPV) and sofosbuvir (SBV). Method I is based on the use of Amax and derivative spectrophotometry with the zero-crossing technique where LPV was determined using its Amax and 1D amplitudes at 324 and 338nm respectively, while SBV was determined by measuring the 1D amplitudes at 276nm. Method II involves the application of the ratio spectra derivative spectrophotometry. For LPV, 12μg/mL SBV was used as divisor and the 1DD amplitudes at 239.8nm were plotted against LPV concentrations; while by using 10μg/mL LPV, the amplitudes at 279.2nm were found proportional to SBV concentrations. Method III depends on ratio-difference measurement where the peak to trough amplitudes between 229.2 and 268.4nm were measured and correlated to LPV concentration. Similarly, the amplitudes between 268.6 and 229.2nm in the SBV ratio spectra were recorded. For method IV, the two compounds were separated using HPTLC sheets of silica gel and a mobile phase composed of chloroform-methanol (94:6) followed by densitometric measurement of LPV and SBV spots at 331 and 267nm respectively. Method V depends on HPLC-DAD. Effective chromatographic separation was achieved using Thermohypersil C8 column (4.6×250mm, 5μm) with a mobile phase consisting of 0.01M sodium dihydrogen phosphate (pH 2.5) and methanol (20:80) at a flow rate 1.2mL/min and detection at 332 and 262nm for LPV and SBV respectively. Analytical performance of the developed methods was validated according to the ICH guidelines with respect to linearity, ranges, precision, accuracy, detection and quantification limits. The validated methods were successfully applied to the simultaneous analysis of LPV and SBV in mixtures of different proportions and their combined tablet dosage form.

Summary A comprehensive stability indicating HPLC with diode array detection method was developed for the determination of the recently approved antiviral drug daclatasvir dihydrochloride (DCV) which is used for the treatment of chronic Hepatitis C Virus (HCV) genotype 3 infection. Effective chromatographic separation was achieved using Waters C8 column (4.6 × 250 mm, 5 μm particle size) with isocratic elution of the mobile phase composed of mixed phosphate buffer pH 2.5 and acetonitrile in the ratio of 75:25 (by volume). The mobile phase was pumped at a flow rate of 1.2 mL/min, and quantification of DCV was based on measuring its peak areas at 306 nm. DCV eluted at retention time 5.4 min. Analytical performance of the proposed HPLC procedure was thoroughly validated with respect to system suitability, linearity, range, precision, accuracy, specificity, robustness, detection and quantification limits. The linearity range was 0.6–60 μg/mL with correlation coefficient > 0.99999. The drug was subjected to forced degradation conditions of neutral, acidic and alkaline hydrolysis, oxidation and thermal degradation. The proposed method proved to be stability-indicating by resolution of the drug from its forced-degradation products. The validated HPLC method was successfully applied to analysis of the cited drug in its tablets.

This work describes the development, validation, and application of two simple, accurate, and reliable methods for the determination of ursodeoxycholic acid (UDCA) in bulk powder and in pharmaceutical dosage forms. The carboxylic acid group in UDCA was exploited for the development of these novel methods. Method 1 is the colorimetric determination of the drug based on its reaction with 2-nitrophenylhydrazine hydrochloride in the presence of a water-soluble carbodiimide coupler [1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride] and pyridine to produce an acid hydrazide derivative, which ionizes to yield an intense violet color with maximum absorption at 553 nm. Method 2 uses reversed-phase HPLC with diode-array detection for the determination of UDCA after precolumn derivatization using the same reaction mentioned above. The acid hydrazide reaction product was separated using a Pinnacle DB C8 column (4.6 × 150 mm, 5 μm particle size) and a mobile phase consisting of 0.01 M acetate buffer (pH 3)–methanol–acetonitrile (30 + 30 + 40, v/v/v) isocratically pumped at a flow rate of 1 mL/min. Ibuprofen was used as the internal standard (IS). The peaks of the reaction product and IS were monitored at 400 nm. Different experimental parameters for both methods were carefully optimized. Analytical performance of the developed methods were statistically validated for linearity,range, precision, accuracy, specificity, robustness, LOD, and LOQ. Calibration curves showed good linear relationships for concentration ranges 32–192 and 60–600 μg/mL for methods 1 and 2, respectively. The proposed methods were successfully applied for the assay of UDCA in bulk form, capsules, and oral suspension with good accuracy and precision. Assay results were statistically compared with a reference pharmacopeial HPLC method, and no significant differences were observed between proposed and reference methods.

This work presents a simple, sensitive and generic high-performance liquid chromatography with diode array detection method for the simultaneous determination of seven drugs prescribed for the treatment of erectile dysfunction and premature ejaculation. Investigated drugs include the phosphodiesterase-5 inhibitors: sildenafil, tadalafil, and vardenafil, in addition to the selective serotonin reuptake inhibitors: dapoxetine, duloxetine, fluoxetine, and paroxetine. The drugs were separated using a Waters C8 column (4.6 × 250 mm, 5 μm) with the mobile phase consisting of phosphate buffer pH 3, acetonitrile and methanol in the ratio 60:33:7. The flow rate was 1.2 mL/min, and quantification was based on measuring peak areas at 225 nm. Peaks were perfectly resolved with retention times 3.3, 3.9, 6.4, 7.5, 9.5, 10.7, and 13.4 min for vardenafil, sildenafil, paroxetine, duloxetine, dapoxetine, fluoxetine, and tadalafil, respectively. The developed method was validated with respect to system suitability, linearity, ranges, accuracy, precision, robustness, and limits of detection and quantification. The proposed method showed good linearity in the ranges 5-500, 2-200, 2-200, 3-300, 1.5-150, 2-200, and 2-200 μg/mL for sildenafil, tadalafil, vardenafil, dapoxetine, duloxetine fluoxetine, and paroxetine, respectively. The limits of detection were 0.18-0.38 μg/mL for the analyzed compounds. The applicability of the proposed method to real life situations was assessed through the analysis of commercial tablets, and satisfactory results were obtained.

This study deals with the development and validation of a comprehensive stability-indicating high performance liquid chromatography with diode array detection (HPLC-DAD) method for simultaneous determination of econazole nitrate (EN), triamcinolone acetonide (TA), benzoic acid (BA) and butylated hydroxyanisole (BHA). To the best of our knowledge, no published methods could be found in the scientific literature for analysis of this quaternary mixture. Effective chromatographic separation was achieved using a Thermo Hypersil BDS C8 column (4.6 × 150 mm, 5 μm particle size) with gradient elution of the mobile phase composed of 0.2% w/v phosphoric acid (adjusted to pH 3.0 using ammonia solution) and methanol. The quantification of EN and BA was based on measuring their peak areas at 225 nm, while the quantification of TA and BHA was based on measuring their peak areas at 242 nm and 290 nm, respectively. BA, TA, BHA and EN peaks eluted at retention times of 8.11, 12.45, 14.28 and 18.36 min, respectively. Analytical performance of the proposed HPLC procedure was thoroughly validated with respect to system suitability, linearity ranges, precision, accuracy, specificity, robustness, and detection and quantification limits. The linearity ranges for EN, TA, BA and BHA were 1.5–300, 1–200, 0.6–100 and 1–100 μg mL−1, respectively, with correlation coefficients >0.9999. The analytes were subjected to forced-degradation conditions of neutral, acidic and alkaline hydrolysis, oxidation and thermal degradation. The proposed method proved to be stability-indicating by resolution of the analytes from their forced-degradation products. Moreover, specificity of the method was verified by resolution of the four analytes from more than 20 pharmaceutical compounds of various medicinal categories. The validated HPLC method was successfully applied to the analysis of the cited compounds in their cream dosage form. The proposed method made use of DAD as a tool for peak identity and purity confirmation.

Benign prostatic hyperplasia (BPH) is one of the most common chronic diseases affecting men and itincreases in both incidence and prevalence with age. This work presents a simple, sensitive and fast gen-eric high performance thin layer chromatographic (HPTLC) method for the simultaneous determinationof five drugs prescribed for the treatment of BPH. These drugs include the a 1 -adrenergic blockers; alfuz-osin hydrochloride (ALF), terazosin hydrochloride (TER), prazosin hydrochloride (PRZ) and doxazosinmesylate (DOX) in addition to the 5 a -reductase inhibitor; finasteride (FIN). The cited drugs were sepa-rated on TLC-silica plates using a mobile phase composed of methylene chloride:n-hexane:methanol(8.8:0.3:0.9, by volume). Densitometric analysis was carried out at 254 nm for the a -blockers whileFIN was measured at 220 nm. The five drugs were detected at R f values of 0.26, 0.36, 0.45, 0.59 and0.69 for ALF, TER, PRZ, DOX and FIN, respectively. The developed method was validated according tothe International Conference on Harmonization (ICH) guidelines regarding; linearity, ranges, accuracy,precision, selectivity, robustness and limits of detection and quantification. The proposed methodshowed good linearity (r > 0.9990) in the ranges; 30–350, 30–350, 20–200, 30–350, 200–2000 ng/spotfor the cited drugs, respectively. The applicability of the proposed method was verified through the anal-ysis of laboratory-prepared mixtures and percentage recoveries between 98.27% and 101.97% wereobtained. Commercial tablets were also analyzed by the developed methodology with no interferencedetected from the co-formulated excipients. The high sensitivity, simplicity and selectivity of the pro-posed method suggest its applicability for routine quality-control analysis purposes of any of the titleddrugs in their pharmaceutical preparations. 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-NDlicense (http://creativecommons.org/licenses/by-nc-nd/3.0/).

Amlodipine besylate (AML) is available in fixed-dose combination tablets with either candesartan cilexetil (CAN) or telmisartan (TEL). This work describes a simple, selective and sensitive spectrofluorimetric method for analysis of AML/CAN and AML/TEL binary mixtures without prior separation. The method involves measurement of the native fluorescence of AML at excitation and emission wavelengths of 367 and 454 nm, respectively, in water without interference from either of the two drugs. By contrast, the intrinsic fluorescence of CAN was measured at excitation and emission wavelengths of 265 and 392 nm, respectively, in ethanol, while TEL was measured at 366 nm in 0.05 M sodium hydroxide solution using 294 nm as the excitation wavelength. The proposed spectrofluorimetric procedure was validated with respect to linearity, ranges, precision, accuracy, selectivity, robustness, detection and quantification limits. Regression analysis showed a good correlation between fluorescence intensity and concentration over the ranges 0.1–1.4, 0.025–0.25 and 0.0025–0.05 µg/mL for AML, CAN and TEL, respectively. Limits of detection were 0.034, 0.0063 and 0.0007 µg/mL for AML, CAN and TEL, respectively. The proposed method was successfully applied for the analysis of several synthetic binary mixtures of different ratios and laboratory-prepared tablets with good recoveries, and no interference from common pharmaceutical additives was observed. Copyright © 2014 John Wiley & Sons, Ltd.

A new simple spectrophotometric method was developed for the determination of binary mixtures without prior separation. The method is based on the generation of ratio spectra of compound X by using a standard spectrum of compound Y as a divisor. The peak to trough amplitudes between two selected wavelengths in the ratio spectra are proportional to concentration of X without interference from Y. The method was demonstrated by determination of two drug combinations. The first consists of the two antihyperlipidemics: atorvastatin calcium (ATV) and ezetimibe (EZE), and the second comprises the antihypertensives: candesartan cilexetil (CAN) and hydrochlorothiazide (HCT). For mixture 1, ATV was determined using 10 μg/mL EZE as the divisor to generate the ratio spectra, and the peak to trough amplitudes between 231 and 276 nm were plotted against ATV concentration. Similarly, by using 10 μg/mL ATV as divisor, the peak to trough amplitudes between 231 and 276 nm were found proportional to EZE concentration. Calibration curves were linear in the range 2.5â40 μg/mL for both drugs. For mixture 2, divisor concentration was 7.5 μg/mL for both drugs. CAN was determined using its peak to trough amplitudes at 251 and 277 nm, while HCT was estimated using the amplitudes between 251 and 276 nm. The measured amplitudes were linearly correlated to concentration in the ranges 2.5â50 and 1â30 μg/mL for CAN and HCT, respectively. The proposed spectrophotometric method was validated and successfully applied for the assay of both drug combinations in several laboratory-prepared mixtures and commercial tablets. Keywords: Spectrophotometric analysis, Ratio spectra, Atorvastatin, Ezetimibe, Candesartan, Hydrochlorothiazide

This work describes five simple and reliable spectrophotometric and chromatographic methods for analysis of the binary mixture of ketorolac tromethamine (KTR) and phenylephrine hydrochloride (PHE). Method I is based on the use of conventional Amax and derivative spectrophotometry with the zero-crossing technique where KTR was determined using its Amax and (1)D amplitudes at 323 and 341nm respectively, while PHE was determined by measuring the (1)D amplitudes at 248.5nm. Method II involves the application of the ratio spectra derivative spectrophotometry. For KTR, 12μg/mL PHE was used as a divisor and the (1)DD amplitudes at 265nm were plotted against KTR concentrations; while - by using 4μg/mL KTR as divisor - the (1)DD amplitudes at 243.5nm were found proportional to PHE concentrations. Method III depends on ratio-difference measurement where the peak to trough amplitudes between 260 and 284nm were measured and correlated to KTR concentration. Similarly, the peak to trough amplitudes between 235 and 260nm in the PHE ratio spectra were recorded. For method IV, the two compounds were separated using Merck HPTLC sheets of silica gel 60 F254 and a mobile phase composed of chloroform/methanol/ammonia (70:30:2, by volume) followed by densitometric measurement of KTR and PHE spots at 320 and 278nm respectively. Method V depends on HPLC-DAD. Effective chromatographic separation was achieved using Zorbax eclipse plus C8 column (4.6×250mm, 5μm) with a mobile phase consisting of 0.05M o-phosphoric acid and acetonitrile (50:50, by volume) at a flow rate 1mL/min and detection at 313 and 274nm for KTR and PHE respectively. Analytical performance of the developed methods was statistically validated according to the ICH guidelines with respect to linearity, ranges, precision, accuracy, detection and quantification limits. The validated spectrophotometric and chromatographic methods were successfully applied to the simultaneous analysis of KTR and PHE in synthetic mixtures of different proportions and laboratory-made ophthalmic solution.

This work presents the development, validation and application of four simple and direct spectrophotometric methods for determination of sodium valproate (VP) through charge transfer complexation reactions. The first method is based on the reaction of the drug with p-chloranilic acid (p-CA) in acetone to give a purple colored product with maximum absorbance at 524nm. The second method depends on the reaction of VP with dichlone (DC) in dimethylformamide forming a reddish orange product measured at 490nm. The third method is based upon the interaction of VP and picric acid (PA) in chloroform resulting in the formation of a yellow complex measured at 415nm. The fourth method involves the formation of a yellow complex peaking at 361nm upon the reaction of the drug with iodine in chloroform. Experimental conditions affecting the color development were studied and optimized. Stoichiometry of the reactions was determined. The proposed spectrophotometric procedures were effectively validated with respect to linearity, ranges, precision, accuracy, specificity, robustness, detection and quantification limits. Calibration curves of the formed color products with p-CA, DC, PA and iodine showed good linear relationships over the concentration ranges 24-144, 40-200, 2-20 and 1-8μg/mL respectively. The proposed methods were successfully applied to the assay of sodium valproate in tablets and oral solution dosage forms with good accuracy and precision. Assay results were statistically compared to a reference pharmacopoeial HPLC method where no significant differences were observed between the proposed methods and reference method.

Four simple, rapid and accurate methods for spectrophoto-metric determination of cepfrozil are presented. Method I and II depend on measuring first derivative peak-trough amplitude of the drug in 0...

Three simple and sensitive spectrophotometric methods for the determination of aminoglutethimide are described. The first method is based on the diazotization of the drug and the reaction product is quantified spectrophotometrically at 273 nm. The second and third methods involve coupling of the diazotized salt of the drug with either ethyl acetoacetate (EAA) in alkaline medium or N-(1-naphthyl)ethylenediamine hydrochloride (NED) in acid medium, to give colored reaction products measurable at 368 nm and 558 nm, respectively. The optimization of different experimental conditions is described. The proposed methods were applied successfully to the determination of amino-glutethimide in tablets with good accuracy and precision. The reliability of the developed methods were established by comparing the obtained results with those given by the official United States Pharmacopeial XXII methods.

Three simple, sensitive and accurate spectrophotometric methods for the determination of non UV absorbing tioconazole in pure form and in pharmaceutical formulations are described. The first method depends upon measuring the second derivative (D2) peak amplitude of tioconazole in 0.1 N hydrochloric acid at 248 nm. The second method involves the reaction of tioconazole with picric acid in chloroform and measuring the first derivative (D1) peak amplitude at 422 nm or the peak trough amplitude at 360-325 nm. The third method is based on the reaction of tioconazole with mercurochrome in methanol to give an intense red colored chromogen measurable at 547 nm. The optimization of different experimental conditions is described. Beer's law is valid over concentrations ranging from 0.4-2 mg%. The methods have been applied successfully to the analysis of dosage forms.

Fourth derivative-difference (ΔD4.) spectrophoto metry is presented for the simultaneous assay of phenylbutazone and oxyphenbutazone as metabolites of bumadizone either in laboratory made mixtures or in human plasma. Phenylbutazone and oxyphenbutazone are determined through the measurement of ΔD4 signals at 293 and 282 nm, respectively. The linear relationship of these values versus concentration of both compoundsin the range 1–5 μg/ml for phenylbutazone and 3–8 μg/ml for oxyphenbutazone permits their determination with high accuracy and good reproducibility. The relative standard deviation is less than 1.35% The proposed method could be used for monitoring bumadizone metabolites.

Differential (ΔA), first derivative- (ΔD1) and second derivative- (ΔD2) differential ultraviolet spectrophotometric methods have been presented for the quantitation of cytarabine and acyclovir in their pharmaceutical formulations such as injections and creams. The methods are based on measuring ΔA, ΔD1 and ΔD2 of the active ingredients in acidic solutions against their basic solutions as blanks. The proposed methods are sensitive, highly specific and advantageous over the conventional UV assays since all interferences of the excipients or irrelevant absorptions are nullified. Accuracy of the analysis with the proposed procedures is significantly greater than the classical spectrophotometry methods.

Second derivative spectrophotometry has been used to determine canrenone (I), the main degredation product in spironolactone (II). Second derivative at 300 nm was found linearly related to concentration in the range of 0.2–1 mg% I has been determined in II down to concentration level of 0.2 mg%. The results were found reproducible with a relative standard deviation of 1.7%.

A rapid first derivative spectrophotometric assay of bretylium tosylate, hyoscine butylbromide, oxyphenonium bromide, cetrimide and benzalkonium chloride in pure and in pharmaceutical formulation is developed, The assay depends upon extracting the picrate salt of these quaternised compounds into chloroform from aqueous medium and measurement of peak amplitude at 430 nm or peak - trough amplitude at 365/330 nm. Linear correlation over the concentration range of 5–20 ug ml−1 of the investigated compounds is obtained. The recovery percentage of the pure compound varied from 99.5 to 100.6%. The developed method is simple, sensitive, accurate and suitable for routine analysis of these quaternised compounds in bulk powder and in pharmaceutical formulations.

A rapid, simple, and accurate first-derivative spectrophotometric method has been established for the determination of either cephalexin or cephradine in urine. Quantitative analysis of each antibiotic was achieved by measuring the peak amplitude at 268 nm. The relative and absolute recoveries ranged from 98.90 to 104.00% for cephalexin and from 97.85 to 105.10% for cephradine. The within-day coefficient of variation varied from 3.27 to 6.45%. The applicability of the method for the determination of the cumulative amount of either cephalexin or cephradine excreted unchanged in urine, following an oral dose containing 500 mg of the drug to a human male volunteer, is demonstrated.

A simple, sensitive and accurate colorimetric method is described for the quantitative determination of pindolol either in the pure form or in its tablets. The method is based on the oxidation of the indole moiety in pindolol with potassium persulphate or hydrogen peroxide—in acid medium—to give a highly coloured product that exhibits maximum absorption at 535 nm and 570 nm, respectively. Beer's law is obeyed over concentrations ranging from 0.07–0.35 mg/10 ml for potassium persulphate and 0.1–0.5 mg/10 ml for hydrogen peroxide with mean recoveries of 99.6±0.6 and 99.8±0.9%, respectively. The method is applied for the assay of pindolol tablets without any interference due to tablet fillers.

A rapid second-derivative spectrophotometric assay procedure has been described for the determination of some benzenoid drugs in pharmaceutical dosage forms. Spectral interference from formulation excipients in simple uv spectrophotometric methods has been eliminated by the application of the proposed method. The different assay parameters, linearity and precision of the method have been assessed. The assay results obtained for eight batches of the pharmaceutical formulations of these drugs are in accord with the declared amounts. The high specificity, ease and simplicity offered by second-derivative spectrophotometry permit unit dose assay of these formulations.

A new and highly sensitive method is presented for the spectrophotometric determination of four imidazoline derivatives: antazoline hydrochloride, tolazoline hydrochloride, xylometazoline hydrochloride and naphazoline nitrate. The method is based on the reaction of the corresponding drug base with 2,6 - dichlorophenol -indophenol (DGPIP) in chloroform to give a blue chromogen exhibiting a maximum at 588 - 603nm. The method could be applied for the quantitative determination of the above drugs either pure or in their pharmaceutical preparations (tablets and nasal drops). The results obtained are accurate and have good reproducibility.

First and second derivative ultraviolet spectrometric methods are described for the estimation of indomethacin, naproxen, and ibuprofen in pharmaceutical dosage forms. The proposed methods permit the rapid, precise, and accurate determination of indomethacin capsules BP, naproxen capsules, and ibuprofen tablets BP. Matrix interference is successfully corrected. The results obtained by first and second derivative techniques are in accord with those obtained by the official assay method.

A simple and sensitive spectrophotometric method for the assay of some cardio-vascular drugs is described. The method is based on the interaction of the drug and p-chloranilic acid (p-CA) to give a stable and intensively coloured ion-pair salt. The drugs used are quinidine sulphate, prenylamine lactate, dipyridamol, hydralazine hydrochloride, tolazoline hydrochloride and pindolol. The optimum experimental conditions for colour development have been studied. Conformity to Beer's law enabled the determination of these drugs in their pharmaceutical preparations. The assay results are in accord with the pharmacopoeal assay results.

This paper describes a spectrophotometric method for the assay of phenothiazines (and also opipramol, which is similar but contains a CC linkage instead of the S atom of the phenothiazines) as the pure drug or in tablets or solutions for injection. The colour is produced by heating a solution of the drug or drug preparation with a solution of chloramine-T. The coloured product can be extracted into chloroform before the colour measurement or the whole process carried out in ethanol solution, the colour of which is then measured.

A comprehensive stability indicating HPLC with diode array detection method was developed for determination of the recently approved phosphodiesterase type 4 (PDE-4) inhibitor roflumilast (RFL). Effective chromatographic separation was achieved using Durashell C18 column (4.6 × 250 mm, 5 μm particle size) with isocratic elution of the mobile phase composed of 0.0065 M ammonium acetate pH 6.3, methanol and acetonitrile in the ratio of 30:35:35 (by volume). The mobile phase was pumped at a flow rate of 1.3 mL/min, and quantification of RFL was based on measuring its peak areas at 251 nm. RFL eluted at retention time 6.2 min. Analytical performance of the proposed HPLC procedure was thoroughly validated with respect to system suitability, linearity, range, precision, accuracy, specificity, robustness, detection and quantification limits. The linearity range was 2.5–200 μg/mL with correlation coefficient >0.9998. The drug was subjected to stress conditions of neutral, acidic and alkaline hydrolysis, oxidation, photolysis and thermal degradation. The proposed method proved to be stability-indicating by resolution of the drug from its forced degradation products. Moreover, specificity of the method was verified by resolution of drug from more than 20 pharmaceutical compounds of various medicinal categories. The validated HPLC method was successfully applied to the analysis of the cited drug in its tablet dosage form. The proposed method made use of DAD as a tool for peak identity and purity confirmation.

A spectrophotometric method for determining some phenothiazines, some tetracyclines and chloramphenicol is described. Chlorpromazine hydrochloride, promazine hydrochloride, promethazine hydrochloride, perphenazine and fluphenazine hydrochloride are reacted with sodium cobaltinitrite in phosphoric acid. The red colour developed is measured at 530, 513, 515, 530 and 500 nm, respectively. Tetracycline hydrochloride, oxytetracycline hydrochloride, chlortetracycline hydrochloride, doxycycline hyclate and demeclocycline hydrochloride are reacted with the reagent in aqueous acetic acid. The yellow colour produced is measured at 256, 294, 262, 243 and 246 nm, respectively. Chloramphenicol is determined similarly to the tetracyclines after hydrolysis with 40% sodium hydroxide solution and the colour is measured at 240 nm. The proposed method has been successfully applied to the determination of these drugs in various pharmaceutical preparations.

A precise colorimetric method is described for the estimation of phenyltoloxamine dihydrogen citrate, diphenhydramine hydrochloride, and chlorpheniramine maleate. The method is based on the interaction of these drugs as n-electron donors with 7,7,8,8-tetracyanoquinodimethane as π-acceptor to give a highly colored radical anion. This is corroborated by electron spin resonance spectroscopy. The colored product is quantitated spectrophotometrically at 843 nm. Beer's law is obeyed in the concentration range 2-6 µg/mL for each drug. Optimization of the experimental conditions is described. The proposed method was applied to the analysis of these drugs in tablet form, and results were in good agreement with those obtained by the official method

The colorimetric determination of mefenamic acid and flufenamic acid with potassium ferricyanide in sodium hydroxide medium is described. The orange product is measured at 464 nm. The molar absorptivities are 1.9 × 103 and 2.9 × 103 1.mole−1.cm−1 for mefenamic acid and flufenamic acid, respectively. The method has been applied successfully to the determination of these drugs in capsules.

A simple and sensitive spectrophotometric method for the assay of codeine, emetine and pilocarpine is described, based on the interaction of these drugs (as n-electron donors) with 2,3-dichloro-5,6-dicyano-p-benzoquinone (as pi -acceptor) to give a highly coloured radical anion which exhibits maximum absorption at 460 nm. Formation of the radical anion has been established by electron spin resonance measurements. Beer's law is obeyed for the alkaloids investigated. The assay results are in accord with pharmacopoeial assay results. The procedure is sufficiently sensitive to permit unit dose assay of the individual alkaloids in pharmaceutical formulations.

Six phenothiazine drugs (chlorpromazine hydrochloride, promethazine hydrochloride, promazine hydrochloride, perphenazine, acetophenazine maleate and trifluoperazine hydrochloride) have been determined by titration with potassium ferricyanide in phosphoric acid medium with Methylene Blue as a screening indicator. The results were in agreement with those obtained by the official methods.

Chlorpromazine hydrochloride, promethazine hydrochloride, promazine hydrochloride, perphenazine, thioridazine hydrochloride, chlorprothexine, opipramol hydrochloride, amitriptyline hydrochloride, imipramine hydrochloride and hydroxyzine hydrochloride are estimated in their pure state and in pharmaceutical formulations by means of the reaction of the free bases with chloranil in dioxan-ethanol medium to give a coloured product with maximal absorbance at 550 nm. The method is precise, accurate and specific and recommended for routine analysis for the drugs mentioned.

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.

The spectrophotometric determination of cephaloridine, cefoxitin sodium and cephalothin sodium using ninhydrin in sulphuric acid is described. The method has been applied successfully to the analysis of injections.

A colorimetric method for the determination of five cephalosporins (cefoxitin sodium, cefotaxime sodium, cephapirin sodium, cephalothin sodium and cephaloridine), based on the blue colour formed by reaction of the cephalosporins with ammonium molybdate, is described. The effects of reagent concentration and reaction conditions are discussed. The proposed method has been applied to the analysis of cephalosporin injections, the results of which are in good agreement with those obtained by the official method of the British Pharmacopoeia.

A simple and sensitive colorimetric method for the assay of quinine sulphate, primaquine diphosphate, amodiaquine hydrochloride and pyrimethamine is described. The method is based on the interaction of the drugs and p-chloranilic acid to give a stable product with an intense colour which can be used for the determination of these antimalarials in their pharmaceutical preparations.

A titrimetric method for the evaluation of some tranquillizers and antidepressants is proposed. The method is based on the oxidation of these drugs by iodine monochloride, in strong acid medium, the iodine liberated being titrated with potassium iodate by the Andrews method. The proposed method is applied successfully for the determination of 9 phenothiazines, 1 thioxanthene, 2 acid hydrazides and 1 dibenzazepine containing a double bond (Opipramol). Tablets, solutions for injection, and drops are also determined by the proposed method. The mechanism of oxidation for each species is suggested and the results obtained agree with these suggestions. Some official and non-official methods for the evaluation of the drugs have been compared with the iodine monochloride method, which is found to be superior in specificity, sensitivity and speed.