Derivative UV Spectrophotometry Research Articles

First-order UV-derivative spectrophotometry in the analysis of omeprazole and pantoprazole sodium salt and corresponding impurities

The first-order UV-derivative spectrophotometry, applying zero-crossing method was developed for the determination of omeprazole (OM), omeprazole sulphone (OMS), pantoprazole sodium salt (PANa), and N-methylpantoprazole (NPA) in methanol–ammonia 4.0% v/v, where the sufficient spectra resolutions of drug and corresponding impurity were obtained, using the amplitudes 1D 304, 1D 307, 1D 291.5 and 1D 296.5, respectively. Method showed good linearity in the ranges (μg ml −1): 1.61–17.2 for OM; 2.15–21.50 for OMS; 2.13–21.30 for PANa and 2.0–20.0 for NPA, accuracy and precision (repeatability and reproducibility). The experimentally determined values of LOD (μg ml −1) were 1.126; 0.76; 0.691 and 0.716 for OM, OMS, PANa and NPA, respectively. The obtained values of 2.91% w/w for OMS and 3.58% w/w for NPA in the presence of their parent drug, by applying the method of standard additions, point out the usage of the proposed method in stability studies. Zero-crossing method in the first-order derivative spectrophotometry showed the impurity–drug intermolecular interactions, due to the possible intermolecular hydrogen bonds, confirmed by divergences of experimentally obtained amplitudes for impurities OMS and NPA in comparison to expected values according to regression equations of calibration graphs.

Simultaneous determination of Indigotin and Ponceau-4R in food samples by using Vierordt's method, ratio spectra first order derivative and derivative UV spectrophotometry

Three sensitive and accurate methods for determination of Indigotin and Ponceau-4R in mixtures by Vierordt's method, ratio spectra first order derivative and first order derivative UV spectrophotometry are described. No separation step was required for these novel methods. Ratio spectra first order derivative and first derivative UV spectrophotometric methods were studied in the wavelength range of 300–700 nm and phosphate buffer pH 7.0 medium. The linearity ranges were found as 1.00–50.00 μg ml −1 for Indigotin and 1.00–52.00 μg ml −1 for Ponceau-4R dyes at developed UV spectrophotometric methods. In order to determine both dyes these procedures were applied to the commercially available food samples containing saccharose and citric acid such as powdered drinks, sweets and jellies. Developed spectrophotometric methods were found accurate, precise, reproducible, directly and easily applicable for the analysis of Indigotin and Ponceau-4R in food samples. The data obtained from these spectrophotometric methods to determine Indigotin and Ponceau-4R dyes in food were compared with data from HPLC methods which have been previously reported. No statistically significant difference was found between these methods.

Analytical methods for the determination of folic acid in a polymeric micellar carrier

Amphiphilic copolymers have been the object of growing scientific interest due to their ability to form polymeric micelles in aqueous environments entrapping lipophilic drugs in their inner core. In this study, polyvinylalcohol substituted with oleic acid was employed as an amphiphilic micellar carrier for folic acid (FA), a model drug similar for its chemical–physical characteristics to methotrexate. In order to investigate the stability of the polymeric micelles, the drug incorporation and the kinetic aspects of drug release from these systems, selective analytical methods are required. The development of three analytical methods suitable for selectively identifying and reliably determining FA contained in the micelles and in the delivery systems is reported. UV derivative (first and second order) spectrophotometry was first applied to the aqueous solution of the FA containing micelles obtained at pH 9.0 and provided a characteristic spectral profiling with sharp peaks, related to the analyte, whose amplitude was used for quantitative application. A second approach involved a solid phase extraction (strong anion exchanger), which provided an effective clean up of the FA micelles solution, allowing accurate analysis to be performed also by a conventional spectrophotometric method. A RP-HPLC method, selectively supplying the FA separation from the micelles’ components, was then used as a reference method to determine the accuracy of the spectrophotometric methods. These methods were applied to various micelle composition and to the delivery system study.

Determination of Fleroxacin in Pure and Tablet Forms by Liquid Chromatography and Derivative UV-Spectrophotometry

Derivative UV-spectrophotometric and liquid chromatographic (LC) methods for fleroxacin determination were validated. In the spectrophotometric assay, first-, second-, third-, and fourth-order measurements were applied with the use of peak-zero and peak-peak techniques. The linear correlation between amplitude of the peak and concentration of the examined drug ranged from 2.0 to 12.0 micro/mL. An isocratic LC analysis was performed on a Purospher ODS column with an acidic mobile phase containing tetrabutylammonium hydroxide. Measurements were made at a wavelength of 285 nm with 4-aminobenzoic acid (PABA) as internal standard. The calibration curve was linear (r = 0.9999) in the studied range of concentration (1.0-10.0 microg/mL). The accuracy (mean recovery, about 100%), precision (relative standard deviation < 1%), selectivity, and sensitivity of the elaborated methods were satisfactory.

Anti-beer Evaluation of Hydrochlorothiazide and Losartan by UV Derivative Spectrophotometry

An UV derivative method for the simultaneous determination of Hydrochlorothiazide (HCT) and Losartan (LST) in the commercial forms was developed. The fourth derivative spectrum from the alcoholic solution was used. HCT can be determined by a specific signal at 330–340 nm, while LST uses the signal around 280–290 nm, common to both products. Into the concentration range of HCT (10.8–500)10−3 mg mL−1 and of LST (20–2400)10−3 mg mL−1, for their mixture in the ratio 1:4, two intervals were identified, one for lower values, for which the absorbance grows with concentration, and one for higher values, in which the absorbance of the solution diminishes as concentration increases. The second behaviour seems to be due to intramolecular reactions of the drugs. For both the intervals, linear regressions were obtained by correlating the spectra signals with the drug concentrations. The best results were obtained by employing the regression equations from the downward section.

Determination of butamyrate citrate in cough preparations by derivative UV spectrophotometry and high performance liquid chromatography.

Derivative spectrophotometric procedures and an isocratic high performance liquid chromatographic method for the determination of butamyrate citrate (Sinecod, Safarol) in cough syrups have been developed. In the spectrophotometric method, direct measurement of the drug at its absorption maxima is impossible because of interference from different absorbing excipients. Extraction of butamyrate citrate was performed with n-pentane/isopropyl alcohol. Quantification was carried out through the use of 1D derivative at a trough depth of 253.6 nm where interferences from other coextracted compounds are negligible. The extraction efficiency expressed as a % recovery and precision were assessed by fortifying placebo syrup(s) with known amounts of the compound. Also, a reversed phase high performance liquid chromatographic method was used with a mobile phase containing 0.015 M aqueous tetraethylammonium hydrogen sulfate, methanol and acetonitrile 40:30:30 adjusted to pH 3.50 with ammonium hydroxide. The retention behavior of butamyrate citrate as a function of both pH and salt concentration in the aqueous portion of the mobile phase was investigated. Quantification was achieved with UV detection at 258 nm based on peak area. The HPLC method clearly separates the analyte from its degradation products derived after storage of samples under different stress conditions such as acid, alkaline, temperature, oxygen and light. The described methods were successfully applied to the determination of butamyrate citrate in commercial pharmaceutical products and in placebo syrups prepared in the laboratory with good accuracy and precision. The results of the present study show that the use of the derivatives and the HPLC procedure provide precise and sensitive methods for the determination of the compound in pharmaceutical formulations.

Application of a classical least-squares regression method to the assay of 1,4-dihydropyridine antihypertensives and their photoproducts

A multicomponent UV spectrophotometric method using a classical least-squares (CLS) algorithm has been developed for the quantitative determination of 1,4-dihydropyridine (DHP) calcium antagonists and respective photoproducts. The procedure was optimized by defining a fractionation scheme for selecting the more useful wavelength ranges to be used in the calibration model. The method is potentially able to be extended to the other drugs of the same family. The recovery values from synthetic mixtures and commercial formulations were verified to be 99.09 and 97.85% for drug parents and degradation products, respectively. The sensitivity for the photoproducts determination was found to be below 0.8%. The results obtained from laboratory mixtures and commercial formulations were compared with those provided by UV derivative spectrophotometry.

Determination of Tartrazine and Ponceau-4R in Various Food Samples by Vierordt's Method and Ratio Spectra First-Order Derivative UV Spectrophotometry

Two spectrophotometric methods have been described for determining Tartrazine and Ponceau-4R in binary mixtures. These methods permit the simultaneous determination of these food colorants in various commercially available food samples which contain saccharose and citric acid. Ratio spectra first-order derivative UV spectrophotometric method was studied in the wavelength range 300–700 nm and phosphate buffer pH 7.0 medium. The linearity range was found to be 1.00–60.00 μg mL −1 for Tartrazine and 1.00–52.00 μg mL −1 for Ponceau-4R dyes by Vierordt's and ratio spectra first-order derivative UV spectrophotometric methods. The values obtained from developed methods and the high-performance liquid chromatographic (HPLC) method given in the literature were compared. It was found that the difference was not statistically important between these methods. It was concluded that developed Vierordt's and ratio spectra first-order derivative UV spectrophotometric methods were accurate, sensitive, precise, reproducible and could be applied easily and directly to the routine analysis of the food samples.

Determination of lamivudine and zidovudine in binary mixtures using first derivative spectrophotometric, first derivative of the ratio-spectra and high-performance liquid chromatography–UV methods

Three methods are presented for the simultaneous determination of lamivudine and zidovudine. The first method depends on first derivative UV spectrophotometry, with zero-crossing and peak-to-base measurement. The first derivative amplitudes at 265.6 and 271.6 nm were selected for the assay of lamivudine and zidovudine, respectively. The second method depends on first derivative of the ratio-spectra by measurements of the amplitudes at 239.5 and 245.3 nm for lamivudine and 225.1 and 251.5 nm for zidovudine. Calibration graphs were established for 1–50 μg/ml for lamivudine and 2–100 μg/ml for zidovudine. In the third method (HPLC), a reversed-phase column with a mobile phase of methanol:water:acetonitrile (70:20:10 (v/v/v)) at 0.9 ml/min flow rate was used to separate both compounds with a detection of 265.0 nm. Linearity was obtained in the concentration range of 0.025–50 μg/ml for lamivudine and 0.15–50 μg/ml for zidovudine. All of the proposed methods have been extensively validated. These methods allow a number of cost and time saving benefits. The described methods can be readily utilized for analysis of pharmaceutical formulations. There was no significant difference between the performance of all of the proposed methods regarding the mean values and standard deviations. The described HPLC method showed to be appropriate for simultaneous determination of lamivudine and zidovudine in human serum samples.

Simultaneous determination of terbinafine HCL and triamcinolone acetonide by UV derivative spectrophotometry and spectrodensitometry

A binary mixture of terbinafine hydrochloride and triamcinolone acetonide was determined by three different methods. The first one concerned with determination of both drugs using first derivative (D 1) spectrophotometric technique at 297 and 274 nm over concentration ranges of 5–30 and 4–24 μg ml −1, with mean percentage accuracies 99.90±0.67 and 100.25±0.49, respectively. The second method depends on ratio-spectra 1st derivative (RSD 1) spectrophotometry at 298 and 248 nm over the same concentration ranges with mean percentage accuracies 100.22±0.51 and 99.93±0.56, respectively. The spectrodensitometric analysis provides a rapid and precise method for the separation and quantitation of both terbinafine hydrochloride and triamcinolone acetonide. The method depends on the quantitative densitometric evaluation of thin layer chromatogram of terbinafine hydrochloride and triamcinolone acetonide at 283 and 238 nm over concentration ranges of 5–25 and 2.5–22.5 μg spot −1, with mean percentage accuracies 100.66±0.51 and 100.27±0.73, respectively. The suggested procedures were checked using laboratory prepared mixtures and were successfully applied for the analysis of their pharmaceutical preparations. The three methods retained their accuracy and precision when applying the standard addition technique. The results obtained by applying the proposed methods were statistically analysed and compared with those obtained by a reported method.

Determination of triamterene and leucovorin in biological fluids by UV derivative-spectrophotometry and partial least-squares (PLS-1) calibration.

The resolution of binary mixtures of triamterene (TAT) and leucovorin (LV) by application of first-derivative spectrophotometry and by application of Partial Least Squares calibration (PLS-1) was performed. Triamterene is determined in presence of leucovorin directly in the absorption spectra at 358 nm, and leucovorin is determined in the first-derivative spectra at 305.6 nm, zero-crossing of the triamterene. The mean recovery values in urine samples were 102 and 97% for TAT and LV, respectively. Partial Least Squares calibration (PLS-1) multivariate calibration of spectrophotometric data, have been applied to the determination of these compounds in serum and in urine without pretreatment of the samples. The absorption spectra of samples of serum or urine, spiked with triamterene and/or leucovorin, were used to perform the optimization of the calibration matrices by PLS-1 method. Mean recovery values were of 107 and 108% for TAT and LV in serum samples, and 98 and 91% for TAT and LV in urine samples.

Simultaneous quantification of promazine hydrochloride and its sulfoxide in pharmaceutical preparations.

The use of derivative UV-spectrophotometry is proposed for the simultaneous quantification of promazine hydrochloride in the presence of sulfoxide, and vice versa. For this purpose, mathematical parameters were established for generating derivative spectra of analytes. The determination of promazine was made using the first-order derivative (deltalambda = 10 nm, second polynomial degree) at 268 nm. The quantification of sulfoxide was achieved by applying third-derivative spectra (deltalambda = 14 nm, sixth polynomial degree) based on measurements of the amplitude at 342 - 344 nm. An elaborated method was successfully used to determine analytes in commercial promazine pharmaceuticals. The obtained results agreed well with those obtained by the HPLC method.

Analysis of glimepiride by using derivative UV spectrophotometric method.

Glimepiride (Amaryl), which is a new oral antidiabetic drug in the sulfonylurea class, was analysed by using second order derivative UV spectrophotometry. The quantification of glimepiride in dimethylformamide was performed in the wavelength range of 245-290 nm at N = 6, ?lambda = 21. The second order derivative spectra was calculated using peak to peak (lambdaDMF = 263.3-268.2 nm), peak to zero (lambdaDMF = 268.2 nm) and tangent (lambdaDMF = 263.3-271.8 nm) method for calibration curves, the linearity range of 1.00-500.00 microg ml(-1) by using the second order derivative UV spectrophotometric method. The developed method was applied to directly and easily to the analysis of the pharmaceutical tablet preparations. R.S.D. were found to be 4.18% (Amaryl tablet; 1 mg) and 2.21% (Amaryl tablet; 2 mg). The method was completely validated and proven to be rugged. The limit of quantitation and the limit of detection were found as 1.00 and 0.4 microg ml(-1), respectively. This validated derivative UV spectrophotometric method is potentially useful for a routine laboratory because of its simplicity, rapidity, sensitivity, precision and accuracy.

Application of H-point standard additions method to spectrophotometric and spectrofluorimetric determinations of glafenine and glafenic acid in mixtures

H-point standard additions method (HPSAM), based on spectrophotometric and spectrofluorimetric measurements, was proposed for simultaneous determination of glafenine (G) and glafenic acid (GA). A study of the absorption spectra of G and GA in various pH media has been carried out. Reasonably resolved UV-absorption spectra were obtained with a solution adjusted at pH 4.5 with citric acid–phosphate buffer. Additionally, the fluorescence properties in aqueous micellar systems of anionic, cationic and non-ionic surfactants were investigated. Well resolved fluorescence spectra were established in aqueous Triton X-100 solution at pH 7.8 (citric acid–phosphate buffer). As a comparative method, UV-derivative spectrophotometry (based on zero-crossing technique) was suggested. First-derivative value at 352 nm ( 1D 352) and second-derivative value at 366 nm ( 2D 366) were selected for the quantification of G and GA, respectively. The relative standard deviations of the proposed methods approximate 2%. The proposed methods were evaluated through the analysis of commercial tablets. The results were accurate and precise.

Determination of nimesulide in pharmaceutical dosage forms by second order derivative UV spectrophotometry

In this study, nimesulide which has been used as an analgesic, antipyretic and anti-inflammatory agent, was analyzed by using second order derivative UV spectrophotometry. The solvent, the degree of derivation, ranges of wavelength and n-value were chosen in order to optimize the conditions. The concentration of nimesulide in its solutions in ethanol and chloroform were determined between the wavelength ranges of 200 and 500 nm ( n=6, Δ λ=21) and in the linearity ranges of 2.0–90.0 μg ml −1 in ethanol and 2.0–50.0 μg ml −1 in chloroform by using the values obtained from the second derivative UV spectrum of the substance. The developed second derivative UV spectrophotometric method was applied to the pharmaceutical preparations such as tablet, sachet (granule) and suspension. Tablet and sachet were analysed in ethanol while the suspension was analysed in chloroform. The results obtained from derivative UV spectrophotometry were compared with those obtained by using HPLC. It was found that the difference was not statistically important between these methods. It was concluded that developed derivative UV spectrophotometric method was accurate, sensitive, precise, reproducible and could be applied directly and easily to the pharmaceutical preparations.

UV derivative spectrophotometric study of the photochemical degradation of nisoldipine

The photodecomposition of nisoldipine ((±)3-isobutyl-5-methyl-1,4-dihydro-2,6-dimethyl-4-(2-nitrophenyl)-pyridine-3,5-dicarboxylate), whereby its 4-(2-nitrosophenyl) pyridine analogue is obtained as the photolytic product, was investigated under daylight exposure by means of UV derivative spectrophotometry. The optimal instrumental parameters (120 nm/min scan speed; 2 nm slit width; Δ λ=10 nm and 5 s response time) for analogue derivative spectra were established for amplitudes 1 D 285 and 2 D 291 (measured to the baseline) of the nitroso analogue assay, as well as for 1 D 386 of the parent compound–nisoldipine assay. Using the first-order derivative spectrum, the minimum detectable amount of nitroso analogue in the presence of nisoldipine was equivalent to an impurity level of 5% and by the second-order derivative spectrum, the determination limit was equivalent to an impurity level of 2%. The degradation of nisoldipine followed within 30 days and the calculated maximal degradation rate was 1.6% per day for nisoldipine raw material, but significantly lower values of 0.19 and 0.15% per day were obtained for Nisoldin® tablets (10 and 5 mg, respectively).

Determination of lisinopril from pharmaceutical preparations by derivative UV spectrophotometry

Determination of lisinopril from pharmaceutical preparations by derivative UV spectrophotometry

Determination of protein and casein in milk by fourth derivative UV spectrophotometry

The aim was to develop a simple and rapid method for determination of milk protein in general, and casein content in particular, in milk without involving preparation procedures such as skimming and casein precipitation. Fresh raw milk samples were diluted with 6 M guanidine-HCl buffer before spectroscopic scanning. The total protein and casein contents of 45 milk samples determined by this method were not statistically significantly different from the values obtained by the reference method based on Kjeldahl determination of N ( p < 0.05). By using fourth derivative UV spectrophotometers, the determination of total protein and casein content in milk can be achieved directly in a single run. Treatments of milk such as heating, homogenization, preservation or hydrolysis with protease had no influence on the accuracy of protein determination in milk by this method. The accuracy of determination with 0.03% total protein and 0.04% casein for the reference method could not be achieved under the condition used, due to the effect of high dilution rate.

Simultaneous Determination of Timolol Maleate and Pilocarpine Hydrochloride in Ophthalmic Solutions by First Derivative UV Spectrophotometry and PLS-1 Multivariate Calibration

ABSTRACT The use of UV spectrophotometry (first-derivative/zero-crossing and zero-order spectra/multivariate calibration) is reported for the analysis of two miotic agents in ophthalmic solutions. The resolution of these mixtures has been accomplished without prior separation or derivatisation by using: 1) first-derivative measurements at two appropriate zero-crossing points: λ1 = 222 nm, where the absorption corresponding to excipients is negligible, and λ2 = 307 nm, where the contribution of pilocarpine and excipients to the overall absorption is negligible, and 2) partial least squares (PLS-1) regression analysis of zero-order spectral data. Although the components show an important degree of spectral overlap, they have been simultaneously determined with high accuracy, and with no interference from ophthalmic solution excipients.

Cefuroxime axetil (CAE) dans le traitement des otites moyennes aigues (OMA) de l'enfant comparativement au cefpodoxime proxetil (CPD)

The degree of deacetylation (DD) is increasingly becoming an important property for chitosan, as it determines how the biopolymer can be applied. Therefore, a simple, rapid and reliable method of determining the DD for chitosan is essential. In this report, the DD of chitosan was determined by nuclear magnetic resonance (NMR), linear potentiometric titration (LPT), ninhydrin test and first derivative UV-spectrophotometry (1DUVS). The DD was calculated on a per mol basis instead of on a per mass basis. This is important as the molecular weights of N-acetyl-d-glucosamine and d-glucosamine are different. By converting the mass of N-acetyl-d-glucosamine and d-glucosamine into mols and calculating for the percentage of d-glucosamine present in the chitosan sample, a more accurate estimation of the DD can be obtained. Of the four methods, there is good correlation between 1DUVS and NMR. The concentration of chitosan solution for 1DUVS analysis was standardised as 0.1000 mg chitosan per ml of 0.0100 M acetic acid solution. The presence of d-glucosamine was corrected for by a reference curve for N-acetyl-d-glucosamine. 1DUVS is easy to perform, sensitive and the interference of other contaminants to the results is minimal compared with the other three methods. Therefore, we advocate 1DUVS to be used as the standard methods for routine determination of DD of chitosan.