Development and validation of an UV derivative spectrophotometric determination of Losartan potassium in tablets

Development and validation of an analytical UV derivative spectrophotometric method to quantify Losartan potassium used as a single active principle in pharmaceutical forms were done. Pharmacopeias have not yet provided an official method for its quantification. A study was carried out of all the parameters established by USP XXIV to validate an analytical method for a solid pharmaceutical form, i.e. linearity, range, accuracy, precision and specificity. All these parameters were found in accordance with the acceptance criteria of Comité de Guías Oficiales de Validación de la Dirección General de Control de Insumos para la Salud de México. Based on the spectrophotometric characteristics of Losartan potassium, a signal at 234 nm of the first derivative spectrum (1D234) was found adequate for quantification. The linearity between signal 1D234 and concentration of Losartan potassium in the range of 4.00-6.00 mg l(-1) in aqueous solutions presents a square correlation coefficient (r2) of 0.9938. The mean recovery percentage was 100.7+/-1.1% and the precision expressed as relative standard deviation (R.S.D.) 0.88%. In addition, the proposed method is simple, easy to apply, low-cost, does not use polluting reagents and requires relatively inexpensive instruments. Then, it is a good alternative to existing methods for determining Losartan potassium in tablets provided that the pharmaceutical dosage form does not contain hydrochlorothiazide as second drug.     

Quantitative determination of ambroxol in tablets by derivative UV spectrophotometric method and HPLC

A derivative UV spectrophotometric method for the determination of ambroxol in tablets was developed. Determination of ambroxol in tablets was conducted by using first-order derivative UV spectrophotometric method at 255 nm (n = 5). Standards for the calibration graph ranging from 5.0 to 35.0 microg/ml were prepared from stock solution. The proposed method was accurate with 98.6+/-0.4% recovery value and precise with coefficient of variation (CV) of 1.22. These results were compared with those obtained by reference methods, zero-order UV spectrophotometric method and reversed-phase high-performance liquid chromatography (HPLC) method. A reversed-phase C(18) column with aqueous phosphate (0.01 M)-acetonitrile-glacial acetic acid (59:40:1, v/v/v) (pH 3.12) mobile phase was used and UV detector was set to 252 nm. Calibration solutions used in HPLC were ranging from 5.0 to 20.0 microg/ml. Results obtained by derivative UV spectrophotometric method was comparable to those obtained by reference methods, zero-order UV spectrophotometric method and HPLC, as far as ANOVA test, F(calculated) = 0.762 and F(theoretical) = 3.89, was concerned.     

Comparison of two derivative spectrophotometric methods for the determination of alpha-tocopherol in pharmaceutical preparations

Simple, sensitive and reliable derivative spectrophotometric methods were developed and validated for determination of alpha-tocopherol in pharmaceutical preparations. The solutions of standard and the sample were prepared in absolute ethanol. The quantitative determination of the drug was carried out using the first derivative values measured at 284, 304 nm and the second derivative values measured at 288, 296 nm. Calibration graphs constructed at their wavelengths of determination were linear in the concentration range of alpha-tocopherol using peak to zero 10-250 microg ml(-1) for first and second derivative spectrophotometric methods. Developed spectrophotometric methods in this study are accurate, sensitive, precise, reproducible, and can be directly and easily applied to Evon dragee form as pharmaceutical preparation. Statistical analysis (Student's t-test) of the obtained results showed no significant difference between the proposed two methods.     

Determination of lornoxicam in pharmaceutical preparations by zero and first order derivative UV spectrophotometric methods

Zero and first order derivative UV spectrophotometric methods were developed for the analysis of lornoxicam (LOR). The solutions of the standards and pharmaceutical samples were prepared in 0.05 N NaOH. Absorbances of LOR were measured at 376 nm for the zero order by measuring height of peak from zero and at 281 and 302 nm for the first order derivative spectrophotometric method by measuring peak to peak height. The linearity ranges were found to be 0.5-35 microg/mL for the zero order and 0.2-75 microg/mL for the first order derivative UV spectrophotometric method. The methods were validated and applied to the determination of LOR in pharmaceutical preparations (tablet and injectable, both containing 8 mg LOR). It was concluded that the methods developed were accurate, sensitive, precise, robust, rugged and useful for the quality control of LOR in pharmaceutical preparations.     

Simultaneous determination of montelukast and loratadine by HPLC and derivative spectrophotometric methods

In this study, high performance liquid chromatography (HPLC) and second derivative spectrophotometry have been used and described for the simultaneous determination of montelukast and loratadine in pharmaceutical formulations. HPLC separation was achieved with a Symmetry C18 column and sodium phosphate buffer (pH adjusted to 3.7): acetonitrile (20:80, v/v) as eluent, at a flow rate of 1.0 ml/min. UV detection was performed at 225 nm. The LC method is simple, rapid, selective and stability indicating for the determination of montelukast. 5-Methyl 2-nitrophenol was used as internal standard for the purpose of quantification of both the drugs in HPLC. In the second-order derivative spectrophotometry, for the determination of loratadine the zero-crossing technique was applied at 276.1 nm, but for montelukast peak amplitude at 359.7 nm (tangent method) was used. Both methods were fully validated and a comparison was made for assay determination of selected drugs in formulations. The results confirm that the methods are highly suitable for its intended purpose.     

Development and validation of an UV spectrophotometric method for determination of gatifloxacin in tablets

A simple, sensitive and accurate spectrophotometric method was developed for the assay of gatifloxacin in raw material and tablets. Validation of the method yielded good results concerning range, linearity, precision and accuracy. The absorbance was measured at 287 nm for gatifloxacin tablet solutions. The linearity range was found to be 4.0-14.0 microg/mL for gatifloxacin. It was also found that the excipients in the commercial tablets did not interfere with the method.     

Comparison of classic and derivative UV spectrophotometric methods for quantification of meloxicam and mefenamic acid in pharmaceutical preparations

The methods for quantitative determination of meloxicam and mefenamic acid in pharmaceuticals by classic spectrophotometry - zero order derivative, first and second order derivatives spectrophotometry is described, using "peak - peak" (P-P) and "peak - zero" (P-O) measurements. The calibration curves are linear within the concentration range of 4.0 - 14.0 microg/mL for meloxicam and 14.0 - 24.0 microg/mL for mefenamic acid. The procedure is simple, rapid and the results are reliable.     

Determination of mirtazapine in tablets by UV spectrophotometric and derivative spectrophotometric methods

Mirtazapine, 1, 2, 3, 4, 10, 14b-hexahydro-2-methyl-pyrazino [2, 1-a] pyrido [2, 3-c] [G.L. Stimmel, J.A. Dopheide and S.M. Stahl, Pharmacotheraphy 17(1) (1997) 10] benzazepine, is a new and well tolerated antidepressant. It blocks pre-synaptic alpha2-adrenergic receptors and postsynaptic serotonin type 2 and type 3 receptors. The drug is rapid and completely absorbed after oral administration. Mirtazapine was analyzed by HPLC and gas chromatography with nitrogen-sensitive detection. In this study, mirtazapine was analyzed by using UV spectrophotometry, first and second order derivative spectrophotometry. The type of solvent, the degree of derivation, range of wavelength and n value were chosen in order to optimize the conditions. The concentration of mirtazapine in its methanolic solutions were determined between the wavelength range of 225-360 nm in the linearity range of 1-100, 2-100 and 1-120 microg ml(-1) by using the values obtained from UV. first-order derivative (n = 5, delta lambda = 17.5 nm) and second-order derivative (n = 9, delta lambda = 31.5 nm) spectrum of the substance, respectively. The developed UV Spectrophotometric, first-order and second-order derivative spectrophotometric methods were applied to a pharmaceutical preparation as tablet form. Developed UV and derivative UV spectrophotometric method in this study are accurate, sensitive, precise, reproducible and can be directly and easily applied to the pharmaceutical preparations.     

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.     

Validation of HPLC and UV spectrophotometric methods for the determination of meropenem in pharmaceutical dosage form

A high-performance liquid chromatographic method and a UV spectrophotometric method for the quantitative determination of meropenem, a highly active carbapenem antibiotic, in powder for injection were developed in present work. The parameters linearity, precision, accuracy, specificity, robustness, limit of detection and limit of quantitation were studied according to International Conference on Harmonization guidelines. Chromatography was carried out by reversed-phase technique on an RP-18 column with a mobile phase composed of 30 mM monobasic phosphate buffer and acetonitrile (90:10; v/v), adjusted to pH 3.0 with orthophosphoric acid. The UV spectrophotometric method was performed at 298 nm. The samples were prepared in water and the stability of meropenem in aqueous solution at 4 and 25 °C was studied. The results were satisfactory with good stability after 24 h at 4 °C. Statistical analysis by Student's t-test showed no significant difference between the results obtained by the two methods. The proposed methods are highly sensitive, precise and accurate and can be used for the reliable quantitation of meropenem in pharmaceutical dosage form.     

UV/VIS spectrophotometric methods for determination of caffeine and phenylephrine hydrochloride in complex pharmaceutical preparations. Validation of the methods

The contents of active substances were determined in a preparation TP-4 (tablets) containing paracetamol, ascorbic acid, caffeine and phenylephrine hydrochloride. For determination of caffeine and phenylephrine hydrochloride, UV/VIS spectrophotometric method was used. The VIS spectrophotometric method based on the reaction of phenylephrine with ninhydrine in sulphuric acid (1.127 kg/l). Validation of methods performed for model mixtures proved those methods were accurate, precise, repeatable and linear in the range from 50% to 150% of the amount declared in the preparation. The content of caffeine and phenylephrine hydrochloride in TP-4, Thompyrin, Panadol Extra, Ring N satisfies the FP V demands.     

Comparison of zero- and second-order derivative spectrophotometric and HPLC methods for the determination of gemcitabine in human plasma

Zero- and second-order derivative spectrophotometric and high-performance liquid chromatography (HPLC) methods were developed and validated for the determination of gemcitabine in human plasma. Spectrophotometrically, gemcitabine was determined by means of zero-order derivative absorbance values (A) at 288 nm and from values from the second-order derivative absorbance values (2D) at 285 nm. Beer's Law was obeyed in the range 0.50-15.0 microg ml(-1). The proposed other method, normal-phase HPLC method for determination of gemcitabine in human plasma was described. Calibration curve was linear over the concentration range 0.20-15.0 microg ml(-1). Quantitation was achieved by diode array detection at 272 nm using 2'-deoxycytidine as internal standard. Results obtained by spectrophotometric and HPLC methods for determination of gemcitabine in human plasma described in this paper showed adequate accuracy, precision and repeatability. No interference was found in plasma at the selected derivative wavelength and chromatographic conditions. According to the statistical comparison, there is no significant difference between the three methods. This is suggested that the three methods are equally applicable.     

UV derivative spectrophotometric and RP-HPLC methods for determination of imidapril hydrochloride in tablets and for its stability assessment in solid state

Two methods for determination of imidapril hydrochloride (IMD) in the form of tablets were developed and the stability-indicative determination of IMD in solid state formulations by means of the proposed methods was investigated. IMD is not a pharmacopeial raw material, therefore there is no official method for its determination and purity assessment. The following analytical techniques were adopted for IMD determination: reverse-phase high performance liquid chromatography (RP-HPLC) and first derivative (1D) ultraviolet spectrophotometry. RP-HPLC analysis was performed with the use of LiChrosfer RP-18 column as a stationary phase and acetonitrile-methanol-phosphate buffer pH 2.0 (60:10:30 v/v/v) as a mobile phase. The proposed method showed good linearity (in a range 40.0 - 400.0 microg/mL), accuracy, precision and selectivity for: IMD, its degradation product, and for oxymetazoline as an internal standard (IS). Additionally, different spectrophotometric methods were tested, and the first derivative spectrophotometry was accepted for further research. This method showed good linearity (in a range 4.0 - 40.0 microg/mL), precision and accuracy. The proposed methods were successfully applied to the pharmaceutical dosage form containing the investigated compound without any interference from the excipients. Finally, the results of the suggested methods were statistically compared using t-Student and F-Snedecor tests in the assessment for their equivalence.     

Simultaneous spectrophotometric determination of cyproterone acetate and estradiol valerate in pharmaceutical preparations by ratio spectra derivative and chemometric methods

Ratio spectra derivative spectrophotometry and two chemometric methods (classical least squares, CLS and inverse least squares, ILS, were proposed for the simultaneous quantitative analysis of a binary mixture consists of cyproterone acetate (CA) and estradiol valerate (EV) in the commercial pharmaceutical preparations. In the ratio spectra derivative method, linear regression equations for both drugs were obtained by measuring the analytical signals at the wavelenghts corresponding to either maximums and minimums in the first derivative spectra of the ratio spectra. In the chemometric techniques, the concentration matrix was prepared by using the synthetic mixtures containing these drugs. The absorbance matrix corresponding to the concentration matrix was obtained by measuring the absorbances at 14 wavelengths in the range 220-290 nm for the zero-order spectra. Two chemometric calibrations were constructed by using the absorbance matrix and concentration matrix for the prediction of the unknown concentrations of CA and EV in their mixture. The numerical values were calculated by using 'MAPLE V' software. The accuracy and the precision of the methods have been determined and they have been validated by analyzing synthetic mixtures containing these two drugs. The proposed methods were successfully applied to a pharmaceutical formulation, sugar-coated tablet, and the results were compared with each other.     

Comparison of derivative spectrophotometric and liquid chromatographic methods for the determination of rofecoxib

Two different UV spectrophotometric methods were developed for the determination of rofecoxib in bulk form and in pharmaceutical formulations. The first method, an UV spectrophotometric procedure, was based on the linear relationship between the rofecoxib concentration and the lambdamax amplitude at 279 nm. The second one, the first derivative spectrophotometry, was based on the linear relationship between the rofecoxib concentration and the first derivative amplitude at 228, 256 and 308 nm. Calibration curves were linear in the concentration range using peak to zero 1.5-35.0 microg x ml(-1). HPLC was carried out at 225 nm with a partisil 5 ODS (3) column and a mobile phase constituted of acetonitrile and water (50 :50 v/v). A linear range was found to be 0.05-35.0 microg x ml(-1). The developed methods were successfully applied for the assay of pharmaceutical dosage form. The statistics of the analytical data is also presented. The results obtained by first derivative spectrophotometry were compared with HPLC and no significant difference was found.     

Flow-through UV spectrophotometric sensor for determination of (acetyl)salicylic acid in pharmaceutical preparations

The solid phase spectrophotometry technique, in which the absorbance of the species of interest sorbed on a solid support is measured directly, was applied to the determination of salicylic acid using flow injection-analysis. Salicylic acid was determined by monitoring of its intrinsic absorbance at 297 nm sorbed on Sephadex QAE A-25 resin placed in an appropriate flow-through cell. The method proposed improves the selectivity compared with the corresponding solution-phase method and the sensitivity is increased by a factor of 30 or more. The flow-through sensor proposed allows working with several calibration lines simply by varying the sample volume injected. Thus, linear dynamic ranges from 1 to 20 and from 2 to 40 microg ml(-1) can be obtained by using 1000 and 300 microl, respectively, with detection limits being 0.064 and 0.135 microg ml(-1). Relative Standard Deviations (RSDs) of 0.52 and 0.38%, and sampling frequencies of 18 and 25 h(-1), respectively, were also achieved. The sensor also allows the indirect determination of acetylsalicylic acid previous hydrolysis on-line to salicylic acid. For acetylsalicylic acid, a linear dynamic range from 5 to 120 microg ml(-1) and 25 h(-1) of sampling frequency (300 microl of sample volume) were obtained. The proposed flow-through sensor has been successfully applied to the determination of both analytes in pharmaceutical preparations.     

Development and validation of spectrophotometric methods for carbapenems in pharmaceutical dosage forms

Simple and sensitive spectrophotometric methods have been developed for the determination of meropenem (MRPM) and doripenem (DRPM). These methods are based on the reduction of Fe(III) into Fe(II) by the drugs and their subsequent prussian blue color formation (λ_max 720 nm) with hexacyanoferrate (III), red color formation (λ_max 510 nm) with 1,10-phenanthroline and red color formation (λ_max 520 nm) with 2,2′-bipyridyl in the methods A, B, and C, respectively. Regression analysis of Beer’s plots showed good correlation for MRPM and DRPM in the concentration range (μg/mL) 0.5–6, 2–10; 2–10, 2–14, and 2–18, 1–8 for the methods A, B, and C, respectively.     

高效液相色谱法及紫外分光光度法测定替加色罗片的含量

目的 :建立替加色罗片剂含量测定的HPLC法和UV法。方法 :HPLC法———采用C18柱 ,流动相为乙腈∶1%十二烷基硫酸钠缓冲溶液 (含0 .95 %冰醋酸 ) =5 6∶4 4。流速 :2mL·min- 1。检测波长 :314nm。柱温 :4 0℃。UV法———在 314nm处测定替加色罗的吸收度。结果 :HPLC法在 0 .1～ 12 0mg·L- 1的范围内 ,将峰面积A与浓度C进行回归处理 ,A =2 8.93C - 14 .4 6 (r =0 .9999,n =6 ) ,日内RSD≤ 1.11% ,日间RSD≤ 3.0 9% ,回收率在 10 0 .4 2 %～ 10 3.82 %之间。UV法在 2～ 2 0mg·L- 1范围内线性良好 ,回归方程为A =5 4.2 8C +0 .0 14 8(r =0 .9998,n =7) ,日内RSD≤ 0 .70 % ,日间RSD≤ 0 .92 % ,回收率在 10 1.0 6 %～ 10 3.0 2 %之间。 2种方法测得 3批样品的标示量百分含量均在规定范围内 (90 %～ 110 % )。结论 :HPLC法和UV法均适用于替加色罗片剂的含量测定 ,由于UV法更简便易行 ,在对有关物质进行了较好控制的情况下 ,此法更为适用     

Development and validation of HPLC method for determination of indomethacin and its two degradation products in topical gel

Indomethacin forms by decomposition two degradation products: 4-chlorobenzoic acid and 5-methoxy-2-methylindoleacetic acid. They have to be monitored together with an active substance both during manufacturing process and storage of pharmaceuticals. European Pharmacopoeia (Ph. Eur. 4) describes titration method for determination of indomethacin, which is not very convenient in this case for practical use. Therefore, high performance liquid chromatography is the method-of-choice enabling determination of active substance and its degradation products during one-step procedure simultaneously and automatically.

We have developed a fast, simple and fully automated analytical method for determination of indomethacin and its two impurities in pharmaceutical preparation using HPLC with UV detection. Various stationary phases were tested, especially new types of Zorbax columns made by Agilent. While the conventional C18 stationary phases were not convenient enough to achieve quick and reliable separation, Zorbax-Phenyl analytical column (75 mm × 4.6 mm, 3.5 μm) enables separation of indomethacin and its two degradation products during 7.5 min. Chromatography was performed using isocratic elution with binary mobile phase composed of acetonitrile and 0.2% phosphoric acid (50:50, v/v) at flow rate 0.6 ml/min. Even faster separation of standards was obtained with analytical column Zorbax SB-CN (150 mm × 4.6 mm, 5 μm). The separation was effected with mobile phase of the same composition, only the flow rate was increased to 1.2 ml/min. The analytical run was shortened to 5 min. Both methods use detection wavelength 237 nm and both can use either ketoprofen or flurbiprofen as internal standard for quantitation.

The first method was finally chosen for validation because of the occurrence of placebo interferences in the case of using Zorbax SB-CN. System suitability parameters and validation parameters including method precision, accuracy, linearity, selectivity and robustness were set up. Afterwards, the method was successfully applied for the practical determination of indomethacin and its degradation products in a topical gel and for compound degradation control during stability studies.