Spectrophotometric Estimation Research Articles

Spectrophotometric Estimation of Donepezil Hydrochloride in pure and dosage forms via ion-pair complex with Erythrosine Dye.

Spectrophotometric Estimation of Donepezil Hydrochloride in pure and dosage forms via ion-pair complex with Erythrosine Dye.

A green perspective on simultaneous HPLC and UV spectrophotometric estimation of Udenafil and Dapoxetine hydrochloride in pharmaceutical formulations

Clinical research has affirmed that the combination of Udenafil and Dapoxetine hydrochloride yields greater improvement in erectile dysfunction compared to the use of individual medications. There is a requirement of precise quantitative method for accurate determination of Udenafil and Dapoxetine when taken together. Consequently, our interest lies in developing and validating analytical methods for the simultaneous estimation of Udenafil and Dapoxetine - Various strategies, such as UV spectrophotometric approaches and an innovative, straightforward, accurate, sensitive, and robust High-Performance Liquid Chromatography (HPLC) procedure, have been explored. An Isocratic HPLC approach was employed using reversed-phase CHEMSIL ODS C18 column (4.6 mm x 250 mm, 5 µm) as a stationary phase and detection wavelength (λ max) 230 nm for the two analytes in the chromatographic column. The mobile phase comprised of (70:30, v/v) mixture of Acetonitrile and 10 mM Ammonium formate buffer having pH 5, adjusted with formic acid. The elution was carried out at a constant flow rate of 1 mL/min. The UV simultaneous equation technique estimated the medicine's quantities and derived a simultaneous equation for DAP and UDN using 2 wavelengths, 230 nm and 298 nm. Furthermore, the two advanced methods underwent rigorous statistical validation, guided by the valuable ICH Q2R1 guidelines, affirming their effectiveness as a successful analytical tool for the concurrent analysis of both tablets in bulk and the synthetic mixture fabricated in the laboratory. To assess the environmental impact of contemporary UV spectrophotometric and HPLC techniques, the Green Analytical Greenness Metric (AGREE) software and the Green Analytical System Index (GAPI) were employed to evaluate the greenness profile. This examination confirmed the method's environmental friendliness concerning solvent usage, chemical ingredients, energy consumption, and waste production. The developed UV method is more sustainable and greener compare to HPLC method for simultaneous estimation of compound, which can be utilised by industry for quantification of each individual drug in their combination products.

Spectrophotometric Determination of Remdesivir Using the Ion Pair Complex Method Using through Alizarin Red S Dye

The research included the development of a simple and practical spectroscopic method for the estimation of remdesivir (RDV) by the ion-pair method, which is based on the interaction of RDV with Alizarin Red S (ARS) at laboratory temperature. Using water as a medium for the reaction, a product Red in color was formed, with a linear relation ranging from 1 to 25 ?g/ml. It gave the highest absorption at wavelength 524 nm, and the complex completed its reaction after an hour, as the value of the sample was a relative standard deviation of no more than 1%, the recovery rate is 100.2429%, and high sensitivity to low concentrations, where she was the values of limit of detection, limit of quantitation were 0.0198, 0.0602 ?g/ml, respectively, detection limit of 0.0139 ?g/mL, and a quantitation limit of 0.0422 ?g/mL. The molar absorptivity is 51340.668 L/mol/cm, and Sandell?s sensitivity value is 0.0117 ?g.cm-2. The recovery values ranged from 99.3088% to 100.5184%, with a relative standard deviation not exceeding 0.7886% for RDV. The method was successfully applied for the estimation of pharmaceutical preparations using both direct and standard addition methods.. KEYWORDS :Alizarin red S, Ion pair, Remdesivir, Spectrophotometric estimation.

Spectrophotometric Estimation of Methyldopa Drug in pure and pharmaceutical formulations

Spectrophotometric Estimation of Methyldopa Drug in pure and pharmaceutical formulations

Improved Spectrophotometric Estimation of Nimodipine in the Pharmaceutical Formulation and Biological Fluids

Nimodipine (NDP) belongs to the class of pharmacological agents known as calcium channel blockers. It is used to treat symptoms resulting from a ruptured blood vessel in the brain (hemorrhage). NDP increases blood flow to injured brain tissues. For its clinical importance, a sensitive, accurate and simple spectrophotometric approach for the evaluation of NDP in bulk, tablet and biological fluids has been developed. The procedure involves the reaction of the reduced NDP with equimolar nitrous acid then followed by coupling with the available γ-resorsolic acid reagent in a basic solution to give a colored azo dye. The resulting azo dye is soluble in water and shows a maximum absorption peak at 436 nm. All the variables which affect the conditions such as the influence of acid, γ-resorsolic acid and alkali concentrations, reaction time and Beer׳s law limits were studied carefully and adjusted. The optimal conditions showed the color of azo-dye was stable for more than 1 h. The method was found linear in the range from 1.0 to 40 μg/mL with a good value of determination coefficient (R2= 0.9988). The molar absorptivity was calculated and set up to be 1.8495x104 L/mol.cm. The detection limits and quantitation limits were also estimated and found to be 0.0059 and 0.0195 μg/mL, correspondingly. The approach was established by estimating NDP in pharmaceutical tablets and biological fluids. The precision (RSD) was calculated to be better than 0.324%, whereas the values of recovery percent and relative errors were in the range of 97.95% to 99.08 % and -3.78% to 2.22%, respectively, without interfering from any common excipients present in the samples. The nature of the yellow dye has been studied between diazotized NDP and γ-resorsolic acid reagent and was equal to 1:1.

Validated Simultaneous Derivative Spectrophotometric Estimation of Azithromycin, Fluconazole and Secnidazole in Bulk and Pharmaceutical Formulation

Two simple, sensitive, accurate and precise spectrophotometric methods were developed and validated for the quantitative determination of Azithromycin (AZI), Fluconazole (FLU) and Secnidazole (SEC) in bulk and tablet dosage form. Method A is based on the first-order derivative (D1) and Method B is based on the second-order derivative (D2) spectrophotometric method. In Method A, absorbance was measured at 215nm, 275nm and 333nm being the zero crossing points for AZI, FLU and SEC respectively. In Method B, absorbance was measured at 220nm, 225nm and 211nm being the zero crossing points for AZI, FLU and SEC respectively. For Method A, all three drugs obey Beer’s law in the concentration range 5-30µg/ml for AZI, 5-60 µg/ml for FLU and 5-40 µg/ml for SEC with correlation coefficients 0.995, 0.998 and 0.998 respectively. For Method B, all three drugs obey Beer’s law in the concentration range 5-35 µg/ml for AZI, 5-40 µg/ml for FLU and 5-40 µg/ml for SEC with correlation coefficients 0.995, 0.999 and 0.998 respectively. Both methods can be used for routine analysis of these three drugs in their pharmaceutical dosage form. Results for analysis of both methods were tested and validated for various parameters according to ICH guidelines. 
 Keywords: Derivative, Azithromycin, Fluconazole, Secnidazole

Comparative Chemical Profiling of a Polyherbal Formulation with Respect to its Ingredient Plants Using Spectrophotometric and High-performance Thin-layer Chromatographic Techniques

Background Guggulutiktam Kashayam (GTK) is a water decoction used in Ayurveda for the treatment of various diseases like skin diseases, ulcers, anemia, thyroid problems, stress, liver disease, and leucorrhoea. It is a polyherbal formulation prepared from specific parts of 28 medicinal plants. Objectives The study aimed at a comparative phytochemical evaluation of an important polyherbal formulation with its ingredient plants. Materials and Methods Chemical profiling of GTK has been carried out in comparison with its ingredient plants. Spectrophotometric estimation of major class compounds and high-performance thin-layer chromatography (HPTLC) profiling were done using a standardized protocol. Results The results of the study showed that the phytochemical contents of the finished formulation are different from those of the ingredient plants, which might be due to the numerous synergistic and antagonistic interactions of numerous chemical components extracted from different ingredient drugs. HPTLC-based comparative chromatograms showed the differences and similarities in certain compounds that are specific to some of the plant ingredients. Conclusion The study established the cumulative chemical interactions of various phytochemicals during the preparation of an important polyherbal formula used in Ayurveda.

An Ecofriendly Novel Spectrophotometric Estimation and Validation of Meloxicam in Bulk Drug and their Dosage Form by mixed Hydrotropic Solubilization Method

Solubility is a crucial factor during estimation of poorly soluble drugs. Literature survey reveals spectrophotometric estimation of poorly soluble drugs are mostly done by employing organic solvents. The drawbacks of organic solvents include higher cost, toxicity, pollution and error due to volatility. Hydrotropic solubilisation method involves increasing the solubility of a poorly soluble drug in water with the addition of hydrotropic agents. Most of NSAIDs like Meloxicam, Mefenamic acid, Aceclofenacetc are poorly soluble in water. Meloxicam was found to be soluble in mixed hydrotropic solution of 10% sodium benzoate and 10% sodium caprylate with maximum absorbance at 364 nm. The developed method was found to be linear in the range of 2-10 µg/ml with correlation coefficient (R2) of 0.9968. The LOD and LOQ of proposed method was found to be 0.2634 µg/ml and 0.7983 µg/ml respectively. A novel, simple, safe, sensitive and cost-effective spectrophotometric estimation method was developed for estimation of Meloxicam using 10% sodium benzoate and 10% sodium caprylate as hydrotropic agent. This solubilization method can be employed to preclude the use of organic solvents for the estimation of poorly soluble drugs.

Validated Analytical Method for Multicomponent Analysis of Famotidine and Ofloxacin in Bulk drug and Tablet Formulation by using UV-Visible Spectrophotometer and RP-HPLC

A simple, sensitive, accurate, precise, and reproducible UV- spectrophotometric method and RP-HPLC methods were developed and validated for the estimation of Famotidine and Ofloxacin in bulk drug and pharmaceutical formulation. The Linearity regression was detected and shows a good linear relationship; in the concentration range of 10-50µg/mL (R2 >0.9908) for famotidine and 10-50µg/mL (r2>0.9913) for ofloxacin. The UV – spectrophotometric estimation was carried out by the first-order derivative spectrophotometric method and absorbance were recorded at 273 and 280nm. Beers range were found to be 5-50µg/mL, respectively for both drugs while, correlation coefficient r2 > 0.9988 and 0.9941 for famotidine and ofloxacin. The isoabsorptive point was found to be 274nm in HPLC optimized mobile phase composition, potassium dihydrogen orthophosphate: methanol (60:40). Chromatographic condition consisted of mobile phase potassium dihydrogen orthophosphate buffer pH 2.3, methanol (60:40v/v), run time 30 min, C-18 column (ODS Hypersil) and flow rate 0.8mL/minute. The retention time for famotidine and ofloxacin were found to be 2.44 min, 7.99 min. respectively, and detection at λmax 274nm for both drugs (overlain spectra). The UV methods and RP-HPLC showed good reproducibility and recovery with the percent relative standard deviation (RSD) less than 5%. As per ICH guidelines, the developed method was validated for linearity, accuracy, precision, Sandell's sensitivity, and repeatability proving its utility in the estimation of famotidine and ofloxacin in house tablet formulation.

Nutritionally improved pasta with Arthrospira platensis: effect of cooking on antioxidant capacity and pigments content

The functionalizing of staple and economic foods, which means adding health-promoting substances, has been visualized as a solution to reduce the concerning increase in diet-related diseases caused by bad-eating patterns. Microalgae represent an innovative way to solve this problem. Arthrospira platensis, microalgae nutritionally rich in bioactive compounds, has been used to develop hard wheat pasta (semolina) to improve its nutritional value and provide antioxidant properties, but there is scarce information about the effect of adding A. platensis in a soft wheat pasta with egg on these parameters. Given that, this work aimed to assess the effect of adding A. platensis at 1, 5, and 10% in a soft wheat pasta added with egg on the nutritional value. Besides, the total phenolic content (TPC), antioxidant capacity (by FRAP and ABTS), and the spectrophotometric estimation of chlorophylls a + b as well as total carotenoids content were determined after and before cooking. The results showed that adding A. platensis at 5% was enough to increase raw pasta's nutritional value, especially protein by 19.27%, TPC by 3.88%, antioxidant capacity by 48.54%, and 66.09% for ABTS and FRAP respectively, as well as chlorophyll a + b (5.89 mg/100g) and total carotenoids (1.31 mg/100g). After the cooking process losses of 7.40, 16.81 and 0.51% were evidenced for TPC, ABTS and FRAP assays, however, remained 10.63, 62.37 and 70.65% higher than the cooked control. Furthermore, increases of 92.19 and 54.96% for chlorophyll a+b and total carotenoids were evidenced. The addition of A. platensis to pasta represents a way to improve the nutritional value regarding protein content, increase antioxidant capacity, and the content of chlorophylls and carotenoids, without statistically significant modifications in the caloric content.
 Keywords: Antioxidant, Arthrospira platensis, Carotenoids, Chlorophylls, Functional Food, Pasta.

Spectroscopic Confirmation of the Nearby, Wide-separation L Dwarf Pair CWISE J061741.79+194512.8AB

We present spectroscopic confirmation of a nearby L dwarf pair, CWISE J061741.79+194512.8AB. Keck/NIRES near-infrared spectroscopy shows that the pair is composed of an L2 dwarf primary and an L4 dwarf secondary. High resolution spectroscopy of the combined light system with Keck/NIRSPEC yields a radial velocity of 29.2 ± 0.3 km s−1 and a projected rotational velocity = km s−1. Our spectrophotometric distance estimate places the system at 28.2 ± 5.7 pc, significantly more distant than originally estimated in Kirkpatrick et al. The angular separation of the components is 1.″31 ± 0.″14, corresponding to a projected physical separation of 37 ± 8 au.

Solvents effect on Spectrophotometric estimation of Bilastine

Bilastine is an anti-histamine used to treat Allergic reactions Two simple UV spectrophotometric methods have been developed for the estimation of Bilastine in bulk and pharmaceutical dosage forms. The absorption maxima (λmax) of Bilastine was found to be 280 nm in Methanol and in 0.1 N Acetic acid observed at 271 nm and Beer-Lambert’s law was obeyed over the concentration range 5-30µg/ml.LOD and LOQ values of Bilastine was found to be 0.102 µg/ml, 0.3097 µg/ml and 0.136 µg/ml, 0.411µg/ml in Methanol and 0.1N Acetic acid respectively. The validation parameters were treated statistically with ‘t’ test and significant differences were observed. The study clearly revealed that the solvents influence the determination of Bilastine. The methods developed were rapid and easy can be applied for the estimation of Bilastine in bulk and pharmaceutical formulations.

Validated Simultaneous Derivative Spectrophotometric Estimation of Diflunisal and Lignocaine in Bulk and Pharmaceutical Formulation

Two simple, sensitive, accurate and precise spectrophotometric methods were developed and validated for the quantitative determination of Diflunisal (DIF) and Lignocaine (LIG) in bulk and pharmaceutical dosage form. Method A is based on the first-order derivative (D1), and Method B is based on the second-order derivative (D2) spectrophotometric method. In Method A, absorbance was measured at 224nm and 264nm being the zero crossing points for DIF and LIG, respectively. In Method B, absorbance was measured at 232nm and 273nm being the zero crossing points for DIF and LIG, respectively. For Method A, the two drugs obeyed Beer's law in the concentration range of 3-39µg/ml for DIF and 4-40 µg/ml for LIG with correlation coefficients 0.999 and 0.995, respectively. For Method B, the two drugs obeyed Beer’s law in the concentration range of 3-30µg/ml for DIF and 4-48µg/ml for LIG with correlation coefficients 0.998 and 0.996, respectively. Both methods can be used for routine analysis of these two drugs in their pharmaceutical dosage form. Results for analysis of both methods were tested and validated for various parameters according to ICH guidelines. 
 Keywords: Derivative, Diflunisal, Lignocaine, first order, second order

Spectrophotometric Estimation of Lanthanum with Alizarine Red S and Triton X-100 -Applications to Water Samples and Urine

This method involves the development of a highly sensitive spectrophotometric procedure to estimate lanthanum in an aqueous medium. The procedure involved the treatment of lanthanum with Alizarine Red S as chromophor reagent in presence of neutral surfactant (Triton X-100). At pH4.5, a soluble red complex was produced and exhibited absorption peak with maximum absorption at 523nm. The calibration graph was linear and compatible to Beer's law over the range of concentration 0.125 to 10.0 µg.ml-1 with determination coefficient (R2=0.9994). The apparent molar absorptivity of the complex La-ARS was found to be 0.7222x104 l.mol-1.cm-1 which corresponds to the sensitivity of Sandell’s index of 0.0192 µg.cm-2. The stoichiometric of the complex was studied and it is equal to 1:2 (La: ARS). The values of LOD, LOQ and the range of recovery percentage were estimated and found to be 0.04182, 0.04434 µg.ml-1 and 96.1% to 103.5%, respectively. The precision (RSD) was also calculated and found to be in the range 0.469 to 1.612. The proposed procedure has been applied successfully for the determination of lanthanum in natural waters and urine sample.

Green spectrophotometric method for the spectral pattern recognition based on fuzzy inference system compared to continuous wavelet transform for the quantitative determination of anti-psoriasis drugs in commercial skin ointment formulation: Comparison with HPLC

In this study, two chemometrics methods, including fuzzy inference system (FIS) along with principal component analysis (PCA) and continuous wavelet transform (CWT) were proposed for the simultaneous spectrophotometric estimation of betamethasone dipropionate (BMD) and calcipotriol (CP) in pharmaceutical dosage form without any pretreatment. The mean recovery and root mean square error (RMSE) related to the nine rules of the FIS was 100.14%, 100.72% and 0.016 and 0.020 for BMD and CP, respectively. CWT with wavelet families of Daubechies (db2) and Coiflet (Coif2) were selected to give the best zero crossing point at a wavelength of 254 nm and 265 nm, as well as the highest coefficient of determination (R2) for BMD and CP, respectively. The limit of detection (LOD) and limit of quantitation (LOQ) were found to be 5 × 10−5, 1.7 × 10−3 μg/mL and 0.0277, 0.0225 μg/mL through the calibration graphs in the linear concentration ranges of 1–10 μg/L for BMD and CP, respectively. The selected wavelet families were successfully applied for chemometric analysis of BMD and CP in synthetic mixtures with satisfactory mean recovery values of 94.67% and 102.43% for BMD and CP, respectively. The proposed spectrophotometric methods were statistically compared to high-performance liquid chromatography (HPLC) using analysis of variance (ANOVA). The proposed analytical techniques were found to be easy, fast, precise, and robust with less solvent consumption for the concurrent analysis of BMD and CP, which can be used instead of chromatography methods in pharmaceutical quality control laboratories.

Utilization of cloud point extraction for enhancement the efficiency of spectrophotometric estimation of milnacipran HCl as anti-depression drug in dosage forms and application to its tablets uniformity testing

Two spectrophotometric techniques that are straightforward, sensitive, accurate, and precise have been created and validated for the detection of a particular antidepressant drug, milnacipran HCl (MCN), in both pure and dosage forms. The method A was based on the reaction of MCN with p-dimethylaminobenzaldehyde (p-DMAB) in an acidic medium, to give a yellow colored Schiff’s base product that can be measured at a maximum wavelength of 400 nm. The concentration range of 60–300 μg/mL, with an excellent correlation coefficient (r2 = 0.9991) and with a relative standard deviation (RSD% = 2.0), complies with Beer’s law under ideal circumstances. The method B approach uses a cloud point extraction (CPE) methodology to measure the amount of the yellow color product utilizing Triton X-114 and cetyltrimethylammonium bromide (CTAB) as surfactants at a maximum wavelength of 410 nm. Beer’s law was obey in the concentration range of 0.2–4.0 μg mL−1, a correlation coefficient (r2 = 0.9995) and a relative standard deviation of (RSD% = 1.70). The best optimized reaction circumstances, including the type of solvent, reagent concentration, reaction time, and molar ratio. Calculations were made about the detection and quantification limits. No interference was seen with the frequently used excipients and additives. The proposed methods for determining MCN in its pharmaceutical formulations were effectively used, and the results for pure MCN and commercial tablets were in good agreement with those from the reported approach.

Simultaneous spectrophotometric estimation of nitrobenzene, aniline, and phenol in a ternary mixture using genetic algorithm

In spectrophotometry, mixtures of chemical constituents cannot be determined simultaneously due to spectral interferences as well as the close λmax wavelength, the wavelength at which a substance absorbs the most photons. Since the spectra of individual components in a ternary mixture overlap, determining the concentration of individual components using the wavelength of maximum absorbance, λmax, can lead to a significant error. In this paper, the concentrations of individual components in ternary synthetic mixtures of nitrophenol, aniline, and phenol were estimated simultaneously using a model based on a genetic algorithm and partial least squares. The spectrophotometric data of ternary mixtures with almost identical spectra of nitrobenzene, aniline, and phenol were calibrated using partial least squares modeling without losing prediction capability, and a genetic algorithm method was used to select the appropriate wavelengths for partial least square calibration. The experimental calibration matrix of 27 samples containing a ternary mixture of nitrobenzene (1.0–20.0 mg L−1), aniline (1.0–15.0 mg L−1), and phenol (4.0–18.0 mg L−1) was designed by measuring the absorbance between 200 and 340 nm at a 1 nm wavelength intervals. The model was verified by using six different mixtures with varying concentrations of nitrobenzene, aniline, and phenol. The root mean square error in the prediction of nitrobenzene, aniline, and phenol was 0.1411, 0.1670, and 0.2861 with the genetic algorithm, and 0.3666, 0.6149, and 0.6279 without the genetic algorithm, respectively. This method can be successfully applied to estimate the components in synthetic mixtures accurately. Since this method is accurate and robust, it can be applied to actual industrial wastewater that contains a mixture of toxic chemicals. This eliminates the complications and costs related to separation and purification prior to the analysis using costly chromatographic methods.

Assessment of 2-Year Storage Conditions on Protein, RNA, and DNA in Unstained Human Tissue Sections, Including a Novel Multiplex Digital Gene Expression Profiling Method with Implications for Biobanking.

Background: Formalin-fixed, paraffin-embedded (FFPE) tissues are a valuable resource for clinical and basic science research. Paraffin blocks and the resulting unstained sections (USS) are often stored for years before being used. Previous studies have evaluated the effects of time, temperature, humidity, and inert gases on preservation of USS; however, no study has examined all four variables together. Methods: In the current work, we prospectively and blindly assessed time points from 0 to 24 months, room versus refrigerated temperature, and presence of a desiccant and/or nitrogen atmosphere on a variety of benign and malignant tissues from North America and Africa. End points included immunohistochemistry (IHC), in situ hybridization (ISH), extracted RNA and DNA quantity and quality, and messenger RNA performance in a novel, multiplexed digital gene expression profiling assay of both housekeeping and tumor-specific genes. Results: We found that using current methods of antigen retrieval, staining, and extraction, the end points of IHC, ISH, RNA, and DNA were well preserved under the various conditions tested, with implications that pre-embedding factors contribute to variability in subsequent tissue integrity. We also document that spectrophotometric estimations of nucleic acid concentrations were in general estimated to be higher than with fluorimetric methods, which may be pertinent to end assay development. We further describe a new multiplex assay, the PlexSet digital gene expression assay, suitable for evaluating RNA quality in FFPE tissues. Conclusion: Altogether, these results may provide helpful guidance with regard to approaches for long-term storage conditions for USS.

An Expeditious Spectrophotometric Estimation of Memantine Hydrochloride by Facile Derivatization Using N,N-Dimethyl Aniline

An Expeditious Spectrophotometric Estimation of Memantine Hydrochloride by Facile Derivatization Using N,N-Dimethyl Aniline

Using of Oxidative - Coupling Reaction in Spectrophotometric Determination of Metoclopramide Hydrochloride in Pharmaceutical Preparations

A simple, sensitive, and rapid spectrophotometric method has been developed for the determination of metoclopramide hydrochloride (METH). The method includes the oxidative coupling reaction of metoclopramide with 2,5-dihydroxybenzoic acid using potassium periodate as an oxidizing agent in an aqueous medium and at pH of 4.5 to give a water-soluble colored product. The highest absorbance occurs at a wavelength of 500 nm. The linear range of Beer's law was within the concentration range of 5-75 µg/ml of (METH) and the value of the molar absorptivity 2.196 x103 l.mol-1.cm-1 and Sandell's index value was equal to 0.0449 µg/ cm2. The relative standard deviation value was ≤ 2.98, while the LOD and LOQ values were 0.059 µg.ml-1 and 0.198 µg.ml-1 respectively. The proposed method was successfully applied in the spectrophotometric estimation of metoclopramide preparations in the form of tablets and injections with acceptable recovery.