Accurate Spectrofluorimetric Method Research Articles

An innovative spectrofluorimetric approach for determination of azelaic acid in bulk and pharmaceutical formulation through derivatization with 9-chloromethylanthracene

A novel simple, selective and accurate spectrofluorimetric method has been developed for quantitation of azelaic acid (AZA) in bulk and cream dosage form. The proposed method depended on the reaction between dicarboxylic moiety of AZA and 9-chloromethylanthracence to produce fluorescent derivative that exhibited maximum fluorescence intensity at 413 nm after being excited at 365 nm. The numerous experimental parameters which affect the reaction product and stability have been carefully studied and optimized. The linearity of the calibration curve constructed has been 0.5–15 µg/ml (y = 26.864x + 31.793, r2 = 0.9999) with 0.143 and 0.434 µg/ml as LOD and LOQ values respectively. The method was used for quantitation of AZA in cream dosage form and the results showed that there was no interference from the cream excipients, the mean % recovery was 100.547% ± 0.775.

Synchronized determination of the novel heart failure combination therapy containing sacubitril calcium and valsartan by a validated spectrofluorimetric method

A sensitive and accurate spectrofluorimetric method was proposed for the determination of Sacubitril calcium and Valsartan simultaneously in binary mixture. The method was established on measuring the native fluorescence of Sacubitril calcium and Valsartan upon excitation at 240 nm in acetonitrile. The emission of Sacubitril calcium was measured at 615 nm. For the determination Valsartan a first derivative ratio method was employed to eliminate any spectral interference. The ratio emission spectra were achieved by dividing the emission spectra of various concentrations of Valsartan by the emission spectrum of Sacubitril calcium (100 ng/ml) then the first derivative of the obtained ratio emission spectra was recorded using the proper smoothing factor. The amplitude at 354.9 nm on the first derivative ratio emission spectrum was used to calculate the concentrations of Valsartan in presence of Sacubitril calcium. The method was linear over the concentration range 100–1000 ng/ml for both Sacubitril calcium and Valsartan. The mean accuracy values were found to be 99.32 ± 0.62 and 99.30 ± 0.70 for Sacubitril calcium and Valsartan, respectively. Statistical comparison between results obtained by the proposed method and a reported method for this drugs showed no significant difference. This developed method was used for the quantitative determination of Sacubitril calcium and Valsartan in both pure and pharmaceutical dosage form.

Facile one-pot green solvent synergized fluorescence reaction for determination of doxorubicin in presence of paclitaxel; co-administered drug, application to stability study and analysis in bulk, vial and biological fluids

A green, fast, simple, economical, ultra-sensitive and accurate spectrofluorimetric method was described in the article for the estimation of Doxorubicin hydrochloride (DOX), a type II topoisomerase enzyme inhibitor either alone and in the presence of co- administered drug; paclitaxel as adjuvant chemotherapy combination in bulk, pharmaceutical dosage form and biological fluids. The proposed method was based on studying the fluorescence demeanor of DOX in different organized media and solvents. The intrinsic fluorescence was found to be greatly enhanced in acidic ethanolic solution. The maximum intensity of fluorescence was observed at 590 nm after excitation at 475 nm. Different experimental parameters were examined and adjusted involving various organized media, solvent, and pH. The methods was validated according to ICH guidelines. The linearity of the method was accomplished in the range of 7 × 10−4–4.0 µg ml−1. The values of LOD and LOQ were 0.2 and 0.6 ng ml−1 respectively. The present method is extremely sensitive enough for determination of traces of the drug in various biological fluids with excellent % recovery. The proposed method was extended to investigate the stability of DOX following various induced degradation protocols including: acidic, alkaline, oxidative and photolytic. In addition, the kinetics of the degradation of DOX was investigated and the apparent first-order rate constant, half-life times and Quantum yield were calculated.

Simple and Accurate Spectrofluorimetric Method for Detecting Citrinin in Red Fermented Rice

Citrinin (CIT)—an established public health threat—is a frequent component of red fermented rice (RFR). Although various quantitative techniques have been developed to detect citrinin in red fermented rice, most of these methods require expensive equipment and specially trained personnel. In this study, a simple and accurate spectrofluorimetric method was developed for detecting citrinin in red fermented rice. The proposed method is based on the measurement of native fluorescence of citrinin in methanol (pH 1.5) at an emission wavelength of 485 nm following excitation at 330 nm. The effect of quenching agents on red fermented rice samples was reduced to negligible levels by highly diluting the sample extraction solutions. The linearity was confirmed over the range from 0 to 0.15 μg/ml, and the limits of detection (LOD) and quantification (LOQ) of citrinin in the red fermented rice samples were 1.0 and 3.0 μg/kg, respectively. The developed method showed intra- and inter-day precision levels from 1.0% to 3.8% and recovery values between 91.6% and 95.0% at fortified levels from 10 to 100 mg/kg. The proposed method offers a good alternative to expensive high-performance liquid chromatography methods and can be used for the quality control of red fermented rice products under ordinary experimental conditions.

A simple and rapid spectrofluorometric determination of pomalidomide in spiked plasma and urine. Application to degradation studies.

A rapid and accurate spectrofluorimetric method for the determination of pomalidomide was developed and validated based on the measurement of its native fluorescence without the need for any derivatization and separation for the first time. The fluorescence intensity of the drug in acetonitrile solution allowed precise detection at 460 nm after excitation at 296 nm. The calibration curve was linear in the concentration range 31.0-500.0 ng/ml. Limit of detection and limit of quantification were found to be 8.04 and 24.36 ng/ml, respectively. Sensitive results allowed the drug to be detected with good recovery (75.46-109.72%) in human plasma and urine using the developed method. The proposed method was validated in terms of linearity, sensitivity, precision, accuracy, recovery, and stability parameters. Pomalidomide was subjected to degradation under various stress conditions (hydrolytic, oxidative and thermal) to demonstrate that the method was stable, indicating and identifying possible degradation products. In addition, the drug was exposed to electrochemical degradation using the chronoamperometry technique for the first time. Characterization of pomalidomide degradation products obtained because of oxidative degradation and electrochemical degradation was carried out using attenuated total reflection Fourier transform infrared spectroscopy, mass spectrometry and high performance liquid chromatography - mass spectrometry methods and possible structures were proposed.

Utility of Cremophor RH 40 as a micellar improvement for spectrofluorimetric estimation of sorafenib in pure form, commercial preparation, and human plasma.

An easy, quick, simple and accurate spectrofluorimetric method was recognized and validated for evaluation of sorafenib (SOR) in pure form and biologically in plasma. Cremophor RH 40 (Cr RH 40) used for enhancing the fluorescence activity of SOR in phosphate buffer (pH7). Cr RH 40 improved the native fluorescence of SOR remarkably in water. The fluorescence spectrum of SOR was observed at 405nm after excitation at 265nm. The linearity appeared to be in the range of 5 to 600ng ml-1 for pure and from 9 to 500ng ml-1 for plasma using the protein precipitation (ppt) method while from 10 to 500ng ml-1 for plasma using liquid-liquid extraction method. The precisions and the accuracy of the estimated method gave satisfactory results. The recommended method was effectively applied for determination of SOR in human plasma with high recovery values. The results of some compounds that are possibly found in plasma were studied. The proposed method was also focused on real volunteers and a drug dissolution test.

A Validated Spectrofluorimetric Method for the Determination of Citalopram in Bulk and Pharmaceutical Preparations Based on the Measurement of the Silver Nanoparticles-Enhanced Fluorescence of Citalopram/Terbium Complexes

A simple, sensitive, and accurate spectrofluorimetric method was developed for the determination of citalopram in bulk and pharmaceutical preparations. The method is based on the enhancement of the weak fluorescence signal (FL) of the Tb (III)-citalopram system in the presence of silver nanoparticles. Fluorescence intensities were measured at 555 nm after excitation at 281 nm. Prepared silver nanoparticles (AgNPs) were characterized by UV-Visible spectra and transmission electron microscopy (TEM). Various factors affecting the formation of citalopram-Tb (III)-AgNPs complexes were studied and optimized. The fluorescence intensity versus concentration plot was linear over the range 0.02-14 μg mL(-1), with an excellent correlation coefficient of 0.9978. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 7.15 × 10(-6) μg mL(-1) and 2.38 × 10(-5) μg mL(-1) respectively. The proposed method was found to have good reproducibility with a relative standard deviation of 3.66% (n = 6). The interference effects of common excipients found in pharmaceutical preparations were studied. The developed method was validated statistically by performing recoveries studies and successfully applied for the assay of citalopram in bulk powder and pharmaceutical preparations. Percent recoveries were found to range from 98.98% to 100.97% for bulk powder and from 96.57% to 101.77% for pharmaceutical preparations.

Spectrofluorimetric method for the determination of sulpiride in pharmaceutical preparations and human plasma through derivatization with 2‐cyanoacetamide

A sensitive and accurate spectrofluorimetric method has been developed for the determination of sulpiride in pharmaceutical preparations and human plasma. The developed method is based on the derivatization reaction of 2-cyanoacetamide with sulpiride in 30% ammonical solution. The fluorescent derivatized reaction product exhibited maximum fluorescence intensity at 379 nm after excitation at 330 nm. The optimum conditions for derivatization reactions were studied and the fluorescence intensity versus concentration plot was found to be linear over the concentration range 0.2-20.0 µg/mL with a correlation coefficient of 0.9985. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.82 and 2.73 ng/mL, respectively. The proposed method was validated according to ICH guidelines. The effects of common excipients and co-administered drugs were also studied. The accuracy of the method was checked using the standard addition method and percent recoveries were found to be in the range of 99.00-101.25% for pharmaceutical preparations and 97.00-97.80% for spiked human plasma. The method was successfully applied to commercial formulations and the results obtained for the proposed method were compared with a high-performance liquid chromatography reference method and statistically evaluated using the Student's t-test for accuracy and the variance ratio F-test for precision. A reaction pathway was also proposed.

Spectrofluorimetric Assessment of Metoclopramide Hydrochloride Using Terbium Doped in PMMA Matrix Optical Sensor

A new, simple and accurate spectrofluorimetric method for the determination of metoclopramide hydrochloride was developed. The metoclopramide hydrochloride can remarkably enhance the luminescence intensity of the Tb(3+) ion doped in PMMA matrix at λ(ex)=360 nm in methanol at pH 6.9. The intensity of the emission band at 545 nm of Tb(3+) ion doped in PMMA matrix is increased due to the energy transfer from metoclopramide hydrochloride to Tb(3+) in the excited stated. The effect of different parameters, e.g., pH, temperature, Tb(3+) concentration, foreign ions that control the fluorescence intensity of the produced ion associate was critically investigated. The calibration curve of the emission intensity at 545 nm shows linear response of metoclopramide over a concentration range of 5 × 10(-5)-5.0 × 10(-8) M with detection limit of 8.7 × 10(-10) M. The method was used successfully for the determination of metoclopramide in pharmaceutical preparations and human serum. The average recovery of 99.48% with standard deviation of 0.32% and 96.98% with standard deviation of 0.4%, of pharmaceutical preparations and human serum respectively, were obtained which compared will with the results obtained from standard LC method of average recovery 99.04% and standard deviation of 0.6% and average recovery of 98.19% with standard deviation of 0.6% of pharmaceutical preparations and human serum, respectively.

Spectrofluorimetric estimation of salbutamol sulphate in différent dosage forms by formation of inclusion complex with β-cyclodextrin

A simple, precise, reproducible and accurate spectrofluorimetric method for estimation of Salbutamol sulphate (SAL) in bulk drug and various dosage forms has been developed. This method is based on formation of inclusion complex of SAL in β-cyclodextrin (BCD) which gives fluorescence at excitation wavelength of 279.6nm and emission wavelength of 609.8nm in water. Formation of inclusion complex of drug with BCD enhances fluorescence intensity of drug leads to increased sensitivity. The developed method was validated according to ICH guidelines with respect to accuracy, precision, linearity, limit of detection, limit of quantification. Linearity was observed in the range of 4–20μg/ ml with correlation coefficient of 0.9982. The simplicity of the method permitted rapid analysis suitable for routine control. The developed method was successfully applied for the estimation of SAL in different marketed dosage forms like tablets, syrup and aerosol.

Development and validation of spectrofluorimetric method for determination of haloperidol in pharmaceutical dosage forms

A simple, sensitive, and accurate spectrofluorimetric method has been developed for the determination of haloperidol in pharmaceutical preparations. The present method is based on the formation of an ion-pair complex between haloperidol and alizarin red S at pH 3.4 which is extractable with chloroform. The ion-pair complex exhibits maximum fluorescence intensity at 564 nm with excitation at 466 nm. The reaction conditions were optimized to obtain maximum fluorescence intensity. The relation between the fluorescence intensity and concentration was found to be linear over the range 0.8-20 microg/mL with detection limit of 0.08 microg/mL. The method was successfully employed for quantitation of the active ingredient haloperidol in pharmaceutical preparations. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant difference between the methods compared in terms of accuracy and precision.

Spectrofluorimetric estimation of salbutamol sulphate in different dosage forms by formation of inclusion complex with β-cyclodextrin

A simple, precise, reproducible and accurate spectrofluorimetric method for estimation of Salbutamol sulphate (SAL) in bulk drug and various dosage forms has been developed. This method is based on formation of inclusion complex of SAL in β-cyclodextrin (BCD) which gives fluorescence at excitation wavelength of 279.6 nm and emission wavelength of 609.8 nm in water. Formation of inclusion complex of drug with BCD enhances fluorescence intensity of drug leads to increased sensitivity. The developed method was validated according to ICH guidelines with respect to accuracy, precision, linearity, limit of detection, limit of quantification. Linearity was observed in the range of 4-20 μg/ml with correlation coefficient of 0.9982. The simplicity of the method permitted rapid analysis suitable for routine control. The developed method was successfully applied for the estimation of SAL in different marketed dosage forms like tablets, syrup and aerosol.

A high-sensitive spectrofluorimetric method for the determination of micromolar concentrations of iron(III) in bovine liver with 4-hydroxyquinoline

A new sensitive, rapid and accurate spectrofluorimetric method, suitable for the determination of micromolar concentrations of iron(III) in bovine liver, using 4-hydroxyquinoline (4-HQ) in an alkaline medium (KOH 2.0 × 10−2 mol/l) as fluorescent agent, is described. The fluorescence intensity of the working solutions was measured at λex 305 nm and λem 380 nm. The observed decrease of the above mentioned intensity was mainly due to the quenching, caused by the interaction between the iron(III) to be analysed and the potentially fluorescent 4-HQ. The accuracy and the precision of the proposed method, after an experimental investigation, could be considered as very satisfactory. Potassium fluoride and triethylenetetramine solutions were successfully used for the masking of those metal cations existing in the bovine liver which interfere seriously with the determination of iron(III).

Spectrofluorimetric determination of diethazine and promethazine in pharmaceutical preparations.

A simple, sensitive and accurate spectrofluorimetric method is described for the quantitative determination of diethazine and promethazine either in the pure form or in its pharmaceuticals. The method is based on the formation of red fluorescent product of these drugs with Au(III). A linear calibration graph is obtained over the range 0.05-100 p.p.m. of diethazine and promethazine.

Flotation-spectrofluorimetric determination of phosphate in natural water using Rhodamine B as an ion-pair reagent

A sensitive and accurate spectrofluorimetric method is described for the determination of phosphate in natural water using Rhodamine B as an ion-pair reagent. A Rhodamine B-molybdophosphate ion pair was floated as a membrane-like substance at the phase boundary between the aqueous phase and a diethyl ether phase. After the aqueous phase had been discarded, the excess of Rhodamine B extracted into the diethyl ether was removed by shaking with 25 ml of 1.0 M hydrochloric acid. The floated ion pair was dissolved by the addition of methanol to the diethyl ether phase. The determination of phosphate was performed by measuring the fluorescence intensity of the organic phase at 573 nm with excitation at 554 nm. The calibration graph was linear up to 0.25 µg of phosphorus with a correlation coefficient of 0.999. Although arsenic(V) caused a positive error, no ions commonly existing in natural water, including silicate, interfere with the determination of phosphate. The proposed method was applied to the determination of phosphate phosphorus in some natural water samples.