Box–Behnken Design Based Development of UV-Reversed Phase High Performance Liquid Chromatographic Method for Determination of Ascorbic Acid in Tablet Formulations

A simple, sensitive, accurate and inexpensive UV-reversed-phase high-performance liquid chromatographic method was developed for the determination of ascorbic acid in tablet formulations. The method was based on the separation of ascorbic acid using a mobile phase of an acetonitrile-NaH2PO4-H3PO4 buffer solution (pH = 3) (5:95 v/v) with a UV detection wavelength of 245 nm and a flow rate of 0.8 mL min−1 at ambient column temperature. The variables of the proposed method, such as acetonitrile fraction (%), flow rate (mL min−1) and column temperature (°C), were optimized on the peak area by response surface methodology via the Box–Behnken design. The mobile phase was passed isocratically, and the separation of ascorbic acid was performed at the retention time of 4.1 min. A calibration graph was obtained and found to be linear in the concentration range of 10–180 µg mL−1. The method suitability was assessed and an asymmetry factor of 1.15 was obtained. The proposed method was successfully applied for the determination of ascorbic acid in tablet formulations and statistically compared with the results of the reference method. The performance of the proposed method was excellent and in agreement with the reference method. The recovery percentage of the proposed and reference methods was in the range of 99.98–100.04% and showed compliance (100 ± 2%) with regulatory guidelines.

Development of stability indicating reversed phase HPLC method for determination of elobixibat in pure form and Laboratory prepared tablets: Application to dissolution study

A simple stability indicating reversed phase HPLC method has been developed for determination of elobixibat in presence of its potential impurities and degradation products. The chromatographic separation was carried on a Thermo scientific Base Deactivated Silica BDS Hypersil-C18 (150 × 4.6 mm; 5 μm) column using a mobile phase of acetonitrile and phosphate buffer (25 mM, pH 2.5) in a ratio of (70:30, volume/volume percentage). The experimental conditions were accurately investigated, and the method was validated according to International Conference on Harmonization ICH guidelines Q2 (R1). The drug was subjected to various stress conditions including acidic, basic, oxidative, and photolytic conditions. The method successfully separates the drug from the three reported impurities and different degradants. The method was also successfully applied for the determination of elobixibat in laboratory prepared tablets (5.0 mg). Analysis shows no interference from excipients and degradation products. The method was also applied for performing in vitro dissolution testing of elobixibat laboratory prepared tablets. Since elobixibat is recently introduced into the market, there are no previous stability studies and no reported analytical methods for its determination. Thus, this study presents a validated and selective method that can be effectively employed in routine quality control studies. This article is protected by copyright. All rights reserved.

Cost-effective and earth-friendly chemometrics-assisted spectrophotometric methods for simultaneous determination of Acetaminophen and Ascorbic Acid in pharmaceutical formulation

The development of analytical chemistry is omnipresent in all fields, this leads to considerable consumption of organic solvents and hazardous reagents with an increase in the production of waste to be treated. In this work, we developed simple, fast, cost-effective and above all environmentally friendly methods for the analysis of Acetaminophen (ACT) and Ascorbic acid (ASC) in synthetic mixtures and pharmaceutical formulation, using UV spectroscopy. Four chemometric methods were studied, including PLS-1 with full-spectrum (Full-PLS) and PLS-1 using three variable selection methods, namely subset selection through a genetic algorithm (GA), uninformative variable elimination using iterative predictor weighting (IPW), and variable selection by sub-window permutation analysis (SwPA). The accuracy of the developed methods was evaluated through the root mean square error of prediction (RMSEP), the mean absolute percentage error (MAPE) and the recovery values. All methods showed more accurate prediction results in comparison with full-PLS calibration. Furthermore, the results indicate that the GA-PLS models showed the highest prediction accuracy among all other models with RMSEP and MAPE values of (0.0494 and 0.610) and (0.0163 and 0.321) for the estimation of ACT and ASC, respectively. The proposed methods were successfully applied to the determination of ACT and ASC in their combined dosage form. In addition, the results obtained were statistically compared to those of the conventionally used HPLC method and were found to be in good agreement. The main advantages of the developed methods over HPLC during routine analysis are that they are faster, inexpensive, simple to perform, without the need for major pretreatment of samples. Besides, no organic solvents are used, and thus toxicity and pollution are avoided.

A sensitive chemiluminescence detection approach for determination of 2,4-dinitrophenylhydrazine derivatized aldehydes using online UV irradiation - luminol CL reaction. Application to the HPLC analysis of aldehydes in oil samples

Aldehydes are toxic carbonyl compounds that are identified in various matrices surrounding us. For instance, aldehydes could be formed during the cooking and frying of foods which affects the food quality and safety. Derivatization is a must for the determination of aldehydes as they lack intrinsic chromophoric groups. 2,4-Dinitrophenyl hydrazine (DNPH) is the most used derivatizing reagent for aldehydes and the formed hydrazones could be determined by either HPLC-UV or LC-MS. However, UV detection is non-sensitive, and the MS equipment is expensive and not widely available. Thus, herein we report a smart chemiluminescence (CL) detection method for the DNPH aldehydes derivatives. These derivatives are supposed to possess photosensitization ability due to the presence of strong chromophoric structures; nitrobenzene and phenyl hydrazone. Upon their UV irradiation, singlet oxygen is found to be produced which then converts the DNPH-aldehyde derivative into hydroperoxide. Next, the hydroperoxide reacts with luminol in an alkaline medium producing a strong CL. An HPLC system with online UV irradiation and online reaction with luminol followed by CL detection was constructed and used for the determination of aldehydes after their derivatization with DNPH. The developed method showed excellent sensitivity with detection limits down to 1.5-18.5 nM. The achieved sensitivity is superior to that obtained by HPLC-UV and LC-MS detection methods for DNPH-aldehydes derivatives. Additionally, our approach is an chemiluminogenic where the DNPH reagent itself does not produce CL which is an excellent advantage. The method was applied successfully for the determination of aldehydes in canola oil samples using simple liquid-liquid extraction showing good recovery (87.0-106.0%), accuracy (87.2-106.6), and precision (RSD≤10.2%). After analysis of fresh and heated oil samples, it was demonstrated that heating of oil, even for short time, strongly elevated the level of their aldehydes' content. At last, it was found that the results of the analysis of aldehydes in oil samples using the proposed method perfectly matched those obtained by a reference LC-MS method.

Correction pen as a hydrophobic/lipophobic barrier plotter integrated with paper-based chips and a mini UV-torch to implement all-in-one device for determination of carbazochrome

The design of a cheap, simple, and handy sensing system for rapid quantitation of pharmaceuticals becomes mandatory to ease drug development procedures, quality control, health care, etc. This work describes a simple, innovative, and easily manufactured paper-based device using a correction pen as a plotter for hydrophobic/lipophobic barriers and graphene quantum dots for recognition and quantification of the hemostatic drug carbazochrome, via fluorescence turn-off mechanism mediated by the inner filter effect. A smartphone-based all-in-one device fitted with an inexpensive 365 nm flashlight as a UV light source and a free image processing software was developed for rapid and reliable interpretation of the fluorescence change from the paper-based device upon introduction of the drug. The simple and convenient steps permit the analysis of many samples in a very short time. The smartphone-based all-in-one device featured excellent sensitivity for carbazochrome with a limit of detection equals to 12 ng/detection zone and good %recovery (100.0 ± 0.4). The reliability of the device was ascertained by favorable statistical comparison with the analogous optimized conventional fluorimetry method and a reference HPLC method. The device has been successfully applied for versatile quantitation of carbazochrome in tablets and on manufacturing equipment surfaces with excellent recoveries. The device offers many green aspects that definitely assist the implementation of the sustainability concept to analytical laboratories. The cost-efficiency, reliability, and ease of fabrication as well as the greenness and user friendship qualify the device for wide application in low-income communities.

Development and optimization of a generic HPLC method for the simultaneous determination of common ingredients in multi component cough and cold oral drug products using chemometrics

The aim of this work was to develop a single, generally applicable high performance liquid chromatography/diode array detector (HPLC/DAD) method for simultaneous determination of the most frequently used cough and cold active substances and their impurities that would be applicable for a number of possible formulation compositions of cough and cold medicines. The compounds that are separated by the method include eleven active substances: paracetamol, phenylephrine HCl, caffeine, ibuprofen, ascorbic acid, propiphenazone, pheniramine maleate, chlorphenamine maleate, pseudoephedrine HCl, dextromethorphan HBr and cetylpyridinium Cl; five of their impurities: 4-aminophenol, 4-nitrophenol, 4`-chloroacetanilide, chlorphenamine impurity C and ephedrine HCl; and two preservatives: sodium benzoate and propyl parahydroxybenzoate. All 18 compounds were successfully separated on a reversed phase (RP)-HPLC column with superficially porous particles using gradient elution with a very simple mobile phase in 14 minutes with excellent sensitivity and resolution. Method optimization was performed by the design of experiments approach. The proposed method has been validated according to ICH guidelines and proved to be suitable for the simultaneous qualitative and quantitative determination of the selected compounds in different cough and cold dosage forms. Keywords: cough and cold active substances and impurities, HPLC/DAD, superficially porous particles, core-shell particles, chemometrics, design of experiments