Spectrophotometric assay of Nicotinamide in Pharmaceutical Dosages

The reaction of nicotinamide and alizarin reagent using charge transfer reaction at a pH of 5.54 lead to produce a red colored compound measured at 527 nm., while the blue colored complex was formed using the oxidation reduction reaction between nicotinamide and chromate at pH 3.49 in the presence of an indigo cochineal dye. Theses tow colored products were measured at 527 and 610 nm respectively using two simple, fast and an accurate spectrophotometric methods. The linearity of the charge transfer method was followed Beer’s law 0.4 - 32 μg while the oxidation reduction method was obeyed Beer’s law from 1.6 - 40 μg in depending on the concentration range. Molar absorptivity was 1.95×104 and 2.16×104 mol−1 cm−1 for the red and blue colored complex respectively. Finally, the values of Sandal’s sensitivity were 0.00626 and 0.00565 μg−2 cm−1 for the first and second methods respectively. These two methods have been applied to quantify the amount of nicotinamide in pharmaceuticals with good recovery.

Design of Experimental Approach Biosensor for the Development and Validation of UV Spectrophotometry Method for Determination of Thiamine in Biological Samples and Tablet Formulation

UV-Visible spectroscopy method has been developed for the analysis of Thiamine in biological and pharmaceutical product, based on a chromogenic derivatizing reaction using PDAB (P- dimethyl amino benzaldehyde) reagent. A Central Composite Design (CCD) design with response surface methodology was executed for optimization of experimental conditions of drug with a smaller number of experimental trials. Three independent factors, the concentration of PDAB, the volume of PDAB reagent, and volume of HCl, were used to construct a mathematical model and study the effects of these independent factors on responses as absorbance. The colored complex exhibits a Red shift with absorption maximum λmax at 425 nm, which was selected as the analytical wavelength. The drug seems to be linear, which was established via the regression analysis from 5-30 μgmL-1, with an R2 value of 0.998.The % RSD for intraday and interday precision was < 2%, with good recovery ranging from 95.02 to 101.43% with biological and pharmaceutical samples. LOD and LOQ of the developed method were found to be 1.51 μg mL-1 and 4.57 μg mL-1.This method can be used in routine analysis of pharmaceutical products containing aromatic primary amines along with an estimation of biological samples like urine, blood, sweat, faeces.

Impact of silver nanoparticles as antibacterial agent derived from leaf and callus of Celastrus paniculatus Willd

Background Celastrus paniculatus Willd. is a rich source of numerous active constituents such as celapanigin, celapagin, malkangunin, celapanin, zeylasteral, pristimerin, and zeylasterone which render medicinal properties to its various parts. Therefore, the present work provides a protocol for the synthesis of AgNPs from in vivo leaf and in vitro developed callus extract of C. paniculatus and both the extracts have great antibacterial potential, which may give immense support for the drug preparation using AgNPs prepared from this valuable medicinal plant. Results High frequencies of calli induced from leaves and its counterpart, i.e., the natural part leaf were selected as the experimental materials for the green synthesis. The collected data exhibited gradual color variations started with whitish color, creamish, and after 8 weeks it ultimately turns into a solid mass of brownish callus. The silver nanoparticles (AgNPs) were synthesized using in vivo fresh leaves and in vitro developed callus extracts with an indication of brown colored complex. Further confirmation of AgNPs synthesis in both the samples was done using UV-visible spectral analysis followed by X-ray diffraction (XRD) analysis, Fourier transformation infrared spectroscopy (FTIR), and scanning electron microscopic (SEM) analysis. Conclusion The antibacterial activity of both extracts reflected the presence of the zone of inhibition in both gram-positive and gram-negative bacteria. AgNPs derived from callus extract showed better results with 24.00 ± 1.00 mm zones of inhibition. This protocol deserves the recognition of the antibacterial potential of AgNPs synthesized from CP plant extracts.

A Rapid and Accurate Non Extractive Procedure For Analyzing Monocrotophos In Environmental Samples By Spectrophotometry

An organophosphorous insecticide monocrotophos is increasingly being utilized in agriculture to control insects on a broad range of crops. In this study a new reaction system using spectrophotometric method for quantitative determination of monocrotophos is proposed. The method is based on the bromination of monocrotophos to form dibromomonocrotophos which react with Potassium iodide-Potassium iodate mixture in the presence of leuco malachite green (LMG) to form a water soluble greenish blue colored complex. The change in absorbance as a criterion of the bromination reaction progress was followed spectrophotometrically. To obtain t he maximum sensitivity the effective reaction variables were optimized. The absorbance maximum was observed at 620 nm. Under optimized experimental conditions calibration graph was linear over the range of 10.0-60.0 µg. The molar absorptivity of the colored system is 3.66×104 L mol-1 cm-1 and sandell’s sensitivity is 0.25×10-2 µg cm-2. The calculated detection limit was 0.44 µg mL-1. The interfering effect of various species was also investigated. The present method was successfully applied to the analysis of monocrotophos in different environmental and water samples.

Antioxidant and Anti-Inflammatory Effects of Anacardium occidentale L. and Anacardium microcarpum D. Extracts on the Liver of IL-10 Knockout Mice

Background. The Anacardium occidentale L. (cashew) and Anacardium microcarpum D. (cajuí) are plants commonly found in Brazil. They present phytochemical compounds with antioxidant and anti-inflammatory action. Therefore, the objective of this study was to analyze the antioxidant and anti-inflammatory activities of ethanolic extracts from leaves of A. occidentale and A. microcarpum and its effect on the hepatic tissue in experimental knockout models after they received Paracetamol®. Methods. Ethanol extracts from A. occidentale and A. microcarpum leaves were prepared. Total phenolics were determined by Folin–Ciocalteau reagent, and flavonoids are based on the complexation reaction with the aluminum metal, forming a colored complex. Fingerprint HPLC was performed to detect phenolic compounds. Knockout IL-10 mice randomly divided into six groups were used and received the following treatments: G1, only water; G2, A. occidentale extract; G3, A. microcarpum extract; G4, Paracetamol®; G5, Paracetamol® + A. occidentale extract (400 mg/kg); G6, Paracetamol® + A. microcarpum extract (400 mg/kg). Biochemical parameters of the blood and differential count of leukocytes were done. Oxidative markers and histopathological analyses were performed on their liver tissue. Results. Phenolic compounds and total flavonoids were detected in both two extracts analyzed. The HPLC fingerprint detected phenolic acid, gallic acid, and catechin flavonoid in the two extracts. Histopathological analyses of the hepatic tissue permitted evaluation of nuclear increase, sinusoid congestion, and inflammatory infiltrate. A. microcarpum presented more antioxidant activity increasing antioxidant enzyme levels and reducing TBARS and carbonyl protein when compared to the other treatments after exposure to Paracetamol®. Histopathological analyses showed a decrease in the inflammatory infiltrate after treatment with extracts. Conclusion. Our findings indicate that both extracts, especially A. microcarpum, can reduce hepatic damage in knockout mice exposed to paracetamol, indicating the curative power of these extracts reducing lipid peroxidation and in the morphofunctional damage to the liver parenchyma.

Spectrophotometric quantification of dolutegravir based on redox reaction with Fe3+/1,10-phenanthroline

Background A simple and sensitive spectrophotometric method was developed for the quantitative measurement of dolutegravir in pure form and pharmaceutical formulation. The present method was based on redox reaction between dolutegravir and ferric chloride, which upon complexation with 1,10-phenanthroline formed an orange-colored complex that showed absorption maximum at 520.0 nm. Results The developed method obeyed linearity in the concentration range of 40.00–140.00 μg/mL. The method was also validated as per International Council for Harmonization guidelines and the results were within acceptance values. The validated method was employed for the determination of dolutegravir in pharmaceutical dosage form and the percentage assay value was found to be 102.5, which is in agreement with its label claimed. Conclusion The developed redox-based colorimetric method could be used in the routine quality control analysis of dolutegravir present in various pharmaceutical dosage forms.

Development of method for determining antioxidant activity of extracts based on deep eutectic solvents.

Antioxidant activity is an important characteristic of plant extracts. One of the methods to determine it, is the phosphomolybdate method, which is based on the formation of a water-soluble colored complex and the spectrophotometric determination of its concentration. Recently, methods for obtaining plant extracts using deep eutectic solvents (DES), consisting of two or more substances, have been actively developed. Many DES contain choline chloride. The presence of choline chloride makes it difficult to determine the antioxidant activity of DES-based extracts by the phosphomolybdate method since an insoluble complex is formed during the reaction. The aim of this work is to modify the phosphomolybdate method for determining the antioxidant activity of DES-based extracts by adding acetone to the mixture to transfer the resulting complex into solution.

Development and validation of colorimetric method for the determination of pregabalin in bulk and pharmaceutical formulations

A simple, accurate and precise colorimetric method was developed for the quantification of pregabalin (PGN) in bulk and pharmaceutical formulations. The method was based on the production of a colored complex by reacting PGN with ascorbic acid in DMSO solvent. The resultant complex exhibits absorption maxima at 390 and 532 nm. The factors that affect the complex development and stability were studied and optimized. The reaction stoichiometry of drug: reagent was found to be 1:2. The method was then validated according to ICH guidelines. Regression analysis of Beer's plot showed good correlation (r2 value more than 0.998) within a concentration range of 5-30μg/ml. Linearity was confirmed by standardized residuals versus fitted value plots using Minitab14 software. The limits of detection and quantification at 390 and 532nm were 1.34μg/ml, 1.09μg/ml and 4.05μg/ml, 3.294μg/ml, respectively. Added recovery measurements were found to be 100.04±2.07% and 99.58 ±1.98% at 390nm and 532nm, respectively, which reflect the accuracy of the method and freedom from interference (relative standard deviation values were less than or equal 0.2%). The average assay for the commercial capsule preparation (PGN 150mg/capsule) was found to be 101.373±0.49 and 101.812±0.73 at 390 and 532nm, respectively. The developed method is an inexpensive, extraction free and can be applied for routine analysis of PGN in most of analytical laboratories.

Micro Evaluation of Sulphonamide in Biological Samples by Coupling Reaction

Sulphonamide is considered a turning point for therapeutic science. Structural changes in sulphonamide can lead to the formation of various drugs used for combating different diseases. Sulphonamide can be used in different applications, such as, antitumor agents, carbonic anhydrase inhibitors, anti-bacterials, hypoglycaemic agents, protease inhibitors, and diuretics. The most important thing for this assay is to find a modified approach to assess sulphonamide by utilizing an organic reaction that depends on a process of coupling between our target material (sulphonamide) with 4-amino antipyrine in basic media of phosphate buffer (pH = 11.3), forming a colored complex containing a higher molar absorptivity (wavelength = 457 nanometers). A preliminary investigation test was done to determine the typical condition for this reaction to determine the concentration curve for the interval 8.25 × 10-9 to 1.15 × 10-2 ppm, and the absorptivity molar was 2.1 × 104 L.mol-1.cm-1, RSD value greater than 1.12%, with a percentage of recovery of approximately 99.88%. We obtained the result and got the approved mole ratio for this reaction about 1:1 (sulphonamide:diazotized amino compound); the value of the stability factor reached 2.8 × 106 L.mol-1. This proposal could be used for a fair assessment for sulphonamide determination, which has different advantages, such as, low-cost economy, no need for an expert, simplicity, no need for more time, and high-quality results in the requirement of rapid and excellent determination. This approach can be utilized for validation of sulphonamide in different active biological samples with higher efficiency.

Investigation of the Interaction of Gadolinium with Several Organic Ligands and Humic Acid by Ligand Competition Using 4-(2-Pyridylazo)-Resorcinol (PAR)

Gd3+ forms a strongly colored complex with 4-(2-pyridylazo)-resorcinol (PAR) in aqueous solutions. We characterized the Gd3+-PAR complex in order to use it as a probe of Gd3+ speciation in the presence of environmentally relevant ligands. The formation of the Gd3+-PAR complex was investigated from pH 5 to 8 in the presence of excess PAR. The absorbance of the Gd3+-PAR complex dramatically increased from pH 5 to 8 and application of the method of continuous variation indicates that the complex was primarily 1:2 Gd(PAR)2 at pH 8. Stability constants for Gd3+ with other ligands can be quantified by competitive displacement of the PAR ligand. To establish the viability of this approach, we measured the stability constants between Gd3+ and several organic acids and carbonate. Our measurements show reasonable agreement with the literature values. We used the competitive displacement approach to establish that humic acids can competitively displace PAR from the Gd(PAR)2 complex.