HPLC-DAD STABILITY INDICATING DETERMINATION OF THE FIXED-DOSE COMBINATION OF NIFUROXAZIDE AND DROTAVERINE HYDROCHLORIDE IN CAPSULES

Alfalfa biomass as a green source for the synthesis of N,S-CDs via microwave treatment. Application as a nano sensor for nifuroxazide in formulations and gastric juice

BACKGROUND

Researchers have investigated different techniques for synthesis of carbon dots. These techniques include Arc discharge, laser ablation, oxidation, water/solvothermal, and chemical vapor deposition. However, these techniques suffer from some limitations like the utilization of gaseous charged particles, high current, high temperature, potent oxidizing agents, non-environmentally friendly carbon sources, and the generation of uneven particle size. Therefore, there was a significant demand for the adoption of a new technology that combines the environmentally friendly aspects of both bio-based carbon sourcing and synthesis technique.

RESULTS

Medicago sativa L (alfalfa)-derived N, S-CDs have been successfully synthesized via microwave irradiation. The N,S-CDs exhibit strong fluorescence (λex/em of 320/420 nm) with fluorescence quantum yield of 2.2 % and high-water solubility. The produced N,S-CDs were characterized using TEM, EDX, Zeta potential analysis, IR, UV-Visible, and fluorescence spectroscopy. The average diameter of the produced N, S-CDs was 4.01 ± 1.2 nm, and the Zeta potential was -24.5 ± 6.63 mv. The stability of the produced nano sensors was also confirmed over wide pH range, long time, and in presence of different ions. The synthesized N, S-CDs were employed to quantify the antibacterial drug, nifuroxazide (NFZ), by fluorescence quenching via inner filter effect mechanism. The method was linear with NFZ concentration ranging from 1.0 to 30.0 μM. LOD and LOQ were 0.16 and 0.49 μM, respectively. The method was applied to quantify NFZ in simulated gastric juice (SGJ) with % recovery 99.59 ± 1.4 in addition to pharmaceutical dosage forms with % recovery 98.75 ± 0.61 for Antinal Capsules® and 100.63 ± 1.54 for Antinal suspension®. The Method validation was performed in compliance with the criteria outlined by ICH.

SIGNIFICANCE AND NOVELTY

The suggested approach primarily centers on the first-time use of alfalfa, an ecologically sustainable source of dopped-CDs, and a cost-effective synthesis technique via microwave irradiation, which is characterized by low energy consumption, minimized reaction time, and the ability to control the size of the produced CDs. This is in line with the growing global recognition of the implementation of green analytical chemistry principles.

Smart green spectrophotometric assay of the ternary mixture of drotaverine, caffeine and paracetamol in their pharmaceutical dosage form

Three green and facile spectrophotometric methods were developed for the assay of Petro® components; drotaverine HCl (DRT), caffeine (CAFF), and paracetamol (PAR). The three methods depend on measuring the absorbance of the studied drugs through their ethanolic solution. The first derivative spectrophotometry (FDS) at (Δλ = 10) were good parameters for DRT and CAFF resolution; DRT and CAFF could be well calibrated using FDS at 320 and 285 nm, respectively. PAR could be estimated at 308 nm utilizing the second derivative spectrophotometry (SDS). Method II relies on the double divisor ratio derivative spectroscopy (DDRDS). The first derivative was applied on each drug where they would be assayed at 309, 288, and 255 nm for DRT, CAFF, and PAR, respectively. Method III depends on the mean centering (MCR) technique. DRT, CAFF, and PAR could be determined at 309, 214, and 248 nm, respectively. The concentrations were rectilinear in the ranges of 2-20 µg/mL for DRT, 1.5-15 µg/mL for CAFF, and 2-40 µg/mL for PAR in double devisor and mean centering but PAR from 5 to 40 µg/mL in derivative method. Method validation was performed according to ICH guidelines assured by the agreement with the comparison method. In addition, greenness assessment of the proposed methods was investigated. The application of the proposed method was extended to analyse tablet dosage form and performing invitro dissolution testing.

White sustainable luminescent determination of nifuroxazide using nitrogen-sulphur co-doped carbon quantum dots nanosensor in bulk and various pharmaceutical matrices

Nifuroxazide (NFX) is an antimicrobial agent that is frequently used as an intestinal antiseptic and recently was proven to have anticancer properties. This work employs the use of nitrogen and sulphur co-doped carbon quantum dots (NSC-dots) luminescent nanoparticles to propose a highly sensitive, sustainable, white and green spectrofluorometric method for NFX detection in bulk and pharmaceutical dosage forms. l-Cysteine and citric acid were the precursors to synthesize water soluble NSC-dots by a quick and environmentally-friendly hydrothermal process. NSC-dots' native fluorescence was measured at λem = 416 nm following excitation at 345 nm. Addition of NFX resulted in quantitative quenching of NSC-dots' luminescence, which represents the principle over which this luminescent method was based. Additionally, the mechanism of fluorescence quenching was studied and discussed. The analytical procedure was validated according to the ICH-guidelines. Linear response for NFX was obtained in the dynamic range 0.04-15 μg mL-1. The estimated NFX detection and quantification limits were 0.005 and 0.015 μg mL-1, respectively. The proposed method was employed for NFX quantification into two commercial pharmaceutical dosage forms. The calculated percentage recoveries (R%), percentage relative standard deviations (RSD%), and percentage error (Er%) were satisfactory. Comparison with other reported methods showed that the proposed method is superior in several aspects. Evaluation of the whiteness of the proposed method using the RGB 12 algorithm combined with the most widely used greenness evaluation tools, the Analytical Eco-Scale and AGREE, demonstrated its superiority and sustainability over other previously published spectrofluorimetric methods for the assay of NFX in various dosage forms.

Electrochemical stripping voltammetrical sensor based on polypyrrole exfoliated polyetheramine-montmorillonite nanocomposite for nanomolar detection of nifuroxazide

A series of polypyrrole/polyetheramine-montmorillonite nanocomposites have been fabricated by the intercalation of different types of polyoxyalkylene amine hydrochloride (Jeffamines: D₄₀₀, D₂₀₀₀, T₅₀₀₀, and T₄₀₃) into montmorillonite layers via the cation-exchange process followed by in situ polymerization of pyrrole. The physicochemical characteristics of as-prepared nanocomposites were investigated using Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), and electrochemical impedance spectroscopy (EIS) instruments. The change of the types of Jeffamine causes a change in the geometrical structure, and surface area of nanocomposites. Noteworthy, the resulting polypyrrole/D₂₀₀₀-montmorillonite ([PDM-50]) nanocomposite exhibited a cauliflower-like shape with a specific surface area (116.2 m² g^-1) with the highest conductivity. Furthermore, the modified stripping voltammetric carbon paste sensor was fabricated based on 1.0% [PDM-50] nanocomposites to detect the drug nifuroxazide (NF). The sensor achieved detection limits (LD) of 0.24, and 0.9 nM of NF in the medication, and human urine fluid, respectively. This sensor showed appropriate repeatability, reproducibility, stability, and selectivity for NF sensing in different fluids accompanied by other interferents.

Analytical method development and validation of spectrofluorimetric and spectrophotometric determination of some antimicrobial drugs in their pharmaceuticals

In this study, three novel, sensitive, simple and validated spectrophotometric and spectrofluorimetric methods have been proposed for estimation of some important antimicrobial drugs. The first two methods have been proposed for estimation of two important third-generation cephalosporin antibiotics namely, cefixime and cefdinir. Both methods were based on condensation of the primary amino group of the studied drugs with acetyl acetone and formaldehyde in acidic medium. The resulting products were measured by spectrophotometric (Method I) and spectrofluorimetric (Method II) tools. Regarding method I, the absorbance was measured at 315nm and 403nm with linearity ranges of 5.0-140.0 and 10.0-100.0μg/mL for cefixime and cefdinir, respectively. Meanwhile in method II, the produced fluorophore was measured at λ_em 488nm or 491nm after excitation at λ_ex 410nm with linearity ranges of 0.20-10.0 and 0.20-36.0μg/mL for cefixime and cefdinir, respectively. On the other hand, method III was devoted to estimate nifuroxazide spectrofluorimetrically depending on formation of highly fluorescent product upon reduction of the studied drug with Zinc powder in acidic medium. Measurement of the fluorescent product was carried out at λ_em 335nm following excitation at λ_ex 255nm with linearity range of 0.05 to 1.6μg/mL. The developed methods were subjected to detailed validation procedure, moreover they were used for the estimation of the concerned drugs in their pharmaceuticals. It was found that there is a good agreement between the obtained results and those obtained by the reported methods.

Micelle-enhanced direct spectrofluorimetric method for the determination of linifanib: Application to stability studies

A new simple stability-indicating spectrofluorimetric method has been developed and validated for the determination of the tyrosine kinase inhibitor, linifanib (LNF). The proposed method makes use of the native fluorescence characteristics of LNF in a micellar system. Compared with aqueous solutions, the fluorescence intensity of LNF was greatly enhanced upon the addition of Tween-80. The relative fluorescence intensity of LNF was measured in a diluting solvent composed of 2% Tween-80: phosphate buffer pH 8.0 (20: 80, v/v) using excitation and emission wavelengths of 290 and 450 nm, respectively. The proposed method was fully validated as per the ICH guidelines. The recorded fluorescence intensity of LNF was rectilinear over a concentration range of 0.3-2 μg/ml with a high correlation coefficient (r = 0.9990) and low limits of detection (0.091 μg/ml) and quantitation (0.275 μg/ml). The applicability of the method was extended to study the inherent stability of LNF under different stress degradation conditions including, alkaline, acidic, oxidative, photolytic and thermal degradation. Moreover, the method was utilized to study the kinetics of the alkaline and oxidative degradation of LNF. The pseudo-first order rate constants and half-lives were calculated.

An eco-friendly direct spectrofluorimetric method for the determination of irreversible tyrosine kinase inhibitors, neratinib and pelitinib: application to stability studies

A new rapid and simple stability-indicating spectrofluorimetric method has been developed for the determination of two irreversible tyrosine kinase inhibitors (TKIs), neratinib (NER) and pelitinib (PEL). The method is based upon measurement of the native fluorescence intensity of both drugs at λ_ex 270 nm in aqueous borate buffer solutions (pH 10.5). The fluorescence intensity recorded at 545 nm (NER) and 465 nm (PEL) were rectilinear over the concentration range of 0.1-10 μg/mL for both drugs with a high correlation coefficient (r > 0.999). The proposed method provided low limits of detection and of quantitation of 0.07, 0.11 μg/mL (NER) and 0.02, 0.05 μg/mL (PEL), respectively. The method was successfully applied for the determination of NER and PEL in bulk powder. The proposed methods were fully validated as per the International Conference on Harmonisation (ICH) guidelines. The application of the method was extended to stability studies of both NER and PEL under different forced-degradation conditions (acidic-induced, base-induced, oxidative, wet heat, and photolytic degradation). Moreover, the kinetics of the base-induced and oxidative degradation of both drugs was investigated and the pseudo-first-order rate constants and half-lives were estimated at different temperatures. Also, an Arrhenius plot was applied to predict the stability behaviour of the two drugs at room temperature. Copyright © 2016 John Wiley & Sons, Ltd.