Derivative Ultraviolet Spectrophotometric Method Research Articles

Development of derivative spectrophotometric method for simultaneous determination of pyrazinamide and rifampicin in cubosome formulation

The ultraviolet spectrophotometry analysis for quantitative assay of drugs is a method accurate, sensitive, selective and reproductive with the advantage of being a simple and less expensive method. In this study, a derivative ultraviolet spectrophotometric method was developed for simultaneous determination of pyrazinamide (PYZ) and rifampicin (RIF). The spectrophotometric method was evaluated according to validation guidelines for specificity, linearity, limits of detection and quantification, precision, accuracy and robustness. The first-derivative spectra were obtained and by the zerocrossing point, the wavelength 247 nm and 365 nm were selected for PYZ and RIF quantification, respectively. No interference from cubosome excipients was detected in the proposed method. The results demonstrated linearity in a range of 4.0 – 12.0 µg/mL with an adequate correlation coefficient for both drugs. The intra and inter-day precision results (RSD < 5%) indicated the reproducibility of the method. The accuracy data showed satisfactory results (RSD < 5%) from recovery test. In addition, the robustness results showed that the PYZ and RIF content were unaffected by the solvent alteration of methanol to methanol:water (99:1, v/v). The derivative ultraviolet spectrophotometric method proved to be an excellent strategy for simultaneous determination of PYZ and RIF.

Simultaneous determination of dorzolamide and timolol by first-order derivative UV spectroscopy in simulated biological fluid for in vitro drug release testing

Dorzolamide hydrochloride and timolol maleate is a well-established fixed-dose combination for the treatment of glaucoma worldwide. The utilization of simulated biological fluids can give a superior understanding of the release mechanisms and practicable in vivo nature of a dosage form that can improve the predictive potential of in vitro drug release testing. No method has been reported so far for the simultaneous estimation of dorzolamide and timolol in simulated tear fluid. In the present study, a simple, precise, and accurate first-order derivative ultraviolet spectrophotometric method for the routine analysis of dorzolamide and timolol in simulated tear fluid is proposed for in vitro drug release testing. The developed method was validated as per International Conference on Harmonization guidelines Q2 (R1). First-order derivative UV spectrophotometry was successfully applied to separate the overlapping peaks of dorzolamide and timolol by measuring peak amplitude at 251.80 nm and absorbance at 295.00 nm, respectively. The method was found to be accurate and precise, with a recovery range of 98.0 –101.0% and low relative standard deviations (<2.0%). The developed method was successfully applied for in vitro drug release testing of in-house in situ gel and marketed eye drops containing dorzolamide and timolol. Various mathematical models were adopted to fit the in vitro drug release profile. It was observed that the drug release of both drugs from the in situ gel and the marketed solution were best fitted by the Higuchi and first-order kinetic models, respectively. Moreover, the analysis of variance (ANOVA) provision was used for the validation of results. Overall, with the advantages of simple and fast operations, as well as reliability, the proposed method offers an ideal platform for routine analysis as compared to other high-cost and time-consuming chromatographic techniques. Having access to such a robust method will encourage the use of simulated tear fluid for in vitro drug release testing of ocular products and help to predict the in vivo performances of ophthalmic preparations.

Selective Methods for Cilostazol Assay in Presence of its Oxidative Degradation Product and Co Formulated Telmisartan Application to Tablet Formulation

A high performance liquid chromatographic method characterized by its rapidness and sensitivity was developed and validated for quantitation of Cilostazol (CIL) and Telmisartan (TEL) in raw material, their synthetic mixture using isocratic technique and monolithic C8 column (3 mm × 4.6 mm i.d., 2 μm pore size highly porous). The mobile phase composed of acetonitrile:0.03 M dihydrogen phosphate buffer (40:60, v/v) at pH 4.5. Quantification was achieved through UV detection at 257 nm using flow rate of 1 mL/min, and Dipyridamole (DIP) was used as internal standard. DIP, CIL, and TEL, retention times were 2.2, 3.9 and 5.1 min. respectively. Peak area ratios of each drug to Dipyridamol internal standard were plotted against concentration of each drug and linear relations were obtained in the range of 0.5-15 μg/mL for CIL 0.25-20 μg /mL for TEL. The method was successfully utilized for the assay of CIL and TEL synthetic mixture. Stability-indicating assay methods (SIAM) were mentioned for separation of CIL in presence of its degradation products. Cilostazol was subjected to acid and alkali hydrolysis, oxidation and photochemical degradation. It was stable under acidic, basic and ultraviolet degradation conditions, but undergoes oxidative degradation, therefore the drug was separated from its oxidative degradation product using our proposed high performance liquid chromatographic and derivative ultraviolet spectrophotometric methods. The first derivative method (D1) depend on measuring the amplitude values at 227 and 257 nm for Cilostazol and oxidative degradate, respectively. From calibration plots, linearity was obtained in the range of 1-35 μg/mL for Cilostazol and 2-50 μg/mL for oxidative degradate. Chromatographic separation of Cilostazol from its oxidative degradate was proceeded using the same mobile phase at pH 3.3. All methods were validated statistically as per International Conference on Harmonization (ICH) recommendations for the studied drugs and Cilostazol oxidative degradate in the concentration range of the suggested methods se ion-pair liquid chromatography was described.

Development and validation of a derivative ultraviolet spectrophotometric method for the determination of darifenacin in tablets using experimental designs and its comparison with chromatographic method

A set of experimental designs was applied to develop and validate a spectrophotometric method using derivative transformation coupled with zero-crossing methodology for the quantification of darifenacin hydrobromide in extended-release tablet form. In the presence of the matricial interference, a central composite (face-centered) design was necessary to reach the best condition without interference in the quantification. The optimal system was confirmed using the function named Derringer’s desirability to assess high precision and low quantification limit. The best condition pointed was the first order to derivative transformation, Δλ = 4, scale factor 150, scanning speed 280 nm/s and anulation point in 239.4 nm as wavelength. From these parameters it was possible to perform the method validation resulting in R2 = 0.999, concentration ranging from 0.10 to 2.50 μg/mL, recovery 98.65% and mean precision 97.67% (RSD = 0.0136). Additionally, robustness was assessed by a Plackett-Burman design, and no significant variability was obtained. The spectrophotometric method was compared with high-performance liquid chromatography method, resulting in no significant difference between the methods.

Development and Validation of a Derivative Ultraviolet Spectrophotometric Method for the Determination of Darifenacin in Tablets Using Experimental Designs and Its Comparison with Chromatographic Method

Development and Validation of a Derivative Ultraviolet Spectrophotometric Method for the Determination of Darifenacin in Tablets Using Experimental Designs and Its Comparison with Chromatographic Method

Flow analysis methods for the direct ultra-violet spectrophotometric measurement of nitrate and total nitrogen in freshwaters

Second derivative ultra-violet spectrophotometric methods are described for the measurement of nitrate and total nitrogen in freshwaters using flow analysis techniques. A simple flow system consisting of a peristaltic pump and a single-reflection flow-through cell was used for the measurement of nitrate. Quantification of total nitrogen using alkaline peroxodisulfate photo-digestion was achieved by incorporating an ultra-violet photo-reactor, a hollow-fibre filter and a debubbler into the flow system. The nitrate system featured a limit of detection of 0.04 mg N L −1, 0.4%RSD (1 mg N L −1 as nitrate, n = 10), a coefficient of determination ( R 2) of 0.9995 over the calibration range 0.0–2.0 mg N L −1, and a data acquisition time of 1.5 s per spectrum. The total nitrogen system featured a limit of detection of 0.05 mg N L −1, 1%RSD (1 mg N L −1 as ammonium chloride, n = 10), a coefficient of determination of 0.9989 over the calibration range 0.0–2.0 mg N L −1, and a throughput of 5 sample h −1 measured in triplicate. Digestions of five model nitrogen compounds returned recoveries of >88%. Determinations carried out using the developed systems show a high degree of agreement with data obtained using reference methods. These methods require no colorimetric reagents and eliminate the requirement for a toxic cadmium reduction column. The overlap of chloride and nitrate spectra in seawater is not eliminated entirely by the use of second derivative spectrophotometry, and consequently the methods are restricted to the analysis of freshwaters.

Study of degradation profile and development of stability indicating methods for cefixime trihydrate

The degradation behavior of cefixime trihydrate was investigated under different stress conditions of acidic hydrolysis, alkaline hydrolysis and oxidation using spectrophotometry. Stability indicating spectrophotometric methods were developed that could separate the drug from its degradation products formed under these stress conditions. The UV spectral characteristics of the drug and degraded products were quite different and zero and first order derivative ultraviolet spectrophotometric methods were used to study the extent of degradation. Cefixime trihydrate was found to degrade extensively under experimental conditions. The methods were validated by establishing the linearity, inter and intraday precision, accuracy, selectivity and specificity.

Saccharin analysis in pharmaceutical and cosmetic preparations by derivative ultraviolet spectrophotometry

Saccharin, a synthetic sweetener constituent of several pharmaceutical and cosmetic preparations, is analyzed qualitatively and quantitatively in the presence of interferences like active ingredients and excipients. A derivative ultraviolet spectrophotometric method employing the second and the fourth orders was used. The calibration data obtained were satisfactory, with a relative precision range of 0.53%-0.72%, and linearity between 0.9998-0.9999. The recovery test results for the toothgel sample ranged between 97.80% and 104.95% in the second order of derivative and between 98.04% and 101.32% in the fourth derivative, respectively, using zero-peak (ZP) and peak-peak (PP) methods. The suspension sample showed values between 97.35% and 104.72% in the second derivative and between 95.94% to 104.41% in the fourth derivative, respectively, employing the zero-peak (ZP) and peak-peak (PP) methods. The proposed method showed precision, accuracy and simplicity.

Quantitative determination of piroxicam in a new formulation (piroxicam-beta-cyclodextrin) by derivative UV spectrophotometric method and HPLC.

A derivative ultraviolet (UV) spectrophotometric method for the determination of piroxicam in piroxicam--beta-cyclodextrin tablets was developed. Phosphate buffer (pH 7.8, 0.1 M) and ethanol were used as a solvent system throughout the study. In this study, determination of piroxicam was conducted by using first order derivative amplitudes at 261.4 nm (n=4). Standards for the calibration graph ranging from 2.40 to 20.0 microg/ml were prepared from working standard. The proposed method is accurate with 99.70%+/-0.50 recovery value and precise with coefficient of variation (CV) of 1.29. The results were compared with those obtained using a high-performance liquid chromatography (HPLC) procedure. A reversed-phase C(18) column with aqueous phosphate buffer:methanol, 60:40, v/v, mobile phase was used. UV detector was set at 254 nm. Calibration solutions used in HPLC were ranging from 5 to 20 microg/ml. Results obtained in HPLC were comparable to those obtained by derivative UV spectrophotometric method.

Identification of aminosuccinyl residues in peptides by second-derivative ultraviolet spectrometry

A second derivative ultraviolet spectrophotometric method for direct identification of aminosuccinyl peptides is described. The advantages and limits of this procedure have been assessed on the basis of results of five model peptides including the aminosuccinyl moiety.

Analysis of hospital-formulated oral liquid preparations by second derivative ultraviolet spectroscopy.

Second derivative ultraviolet spectrophotometric methods have been devised for the analysis of hospital-formulated oral liquid preparations. These rapid techniques are useful in the routine quality control of oral liquid formulations where direct spectrophotometric determination of the drug analyte is precluded by interference from formulation excipients and colouring agents. This report describes examples in which the active principles of a dipipanone mixture, a methadone mixture and an orphenadrine syrup were determined by derivative spectroscopy. In each case spectral interference from formulation excipients was abolished. The accuracy, precision and specificity of each method has been established.