Green monitoring of bromhexine oxidative degradation kinetics

Fabrication of novel electropolymerized conductive polymer of hydrophobic perfluorinated aniline as transducer layer on glassy carbon electrode: application to midazolam as a model drug of benzodiazepines

The objective of this study is to fabricate solid-contact ion selective electrodes (SC-ISEs) that have long term stable potential. Various conducting polymers such as polyaniline and its derivatives have been successfully employed to improve the potential stability in SC-ISEs. Recently, the role of hydrophobicity at the interface between the conducting polymer solid contact and the ion sensing membrane has been investigated and figured out that the hydrophobic interfaces preclude water layer formation that deteriorate the SC-ISEs potential stability and reproducibility. In this work, a hydrophobic polyaniline derivative was fabricated on the surface of a glassy carbon electrode by electropolymerization of perfluorinated aniline monomers in acidic solution. The electropolymerized hydrophobic polymer was characterized by electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy. The fabricated electrode was employed for determination of midazolam-a model drug-in pharmaceutical formulation without prior extraction. The SC-ISEs performance was optimized, and the potential drift was compared to control SC-ISEs, the SC-ISE linear range was 1 × 10^-6-1 × 10^-2 M, LOD was estimated to be 9.0 × 10^-7 M, and potential drift was reduced to 100 μV/h.

Greenness Assessment of Two Validated Stability Indicating Chromatographic Methods for Estimating Modafinil Using Analytical Eco-Scale

BACKGROUND

Modafinil (MDF) is one of the drugs that used for the treatment of narcolepsy.

OBJECTIVE

This manuscript involves the development and validation of two chromatographic stability indicating methods for MDF in the presence of its acid induced degradation.

METHODS

Modafinil was degraded under different stress conditions and identification of the degradation product was performed using infrared and mass spectroscopy. The first method was thin layer chromatography where aluminum backed silica gel 60F254 plates were used and the developing system was dichloromethane- methanol (9:1, v/v). While the second method was an eco- friendly (HPLC) that utilized C-18 column and ethanol- H2O (30:70, v/v) as a mobile phase at flow rate 1 mL/min and UV detection at 220 nm.

RESULTS

Good linear relationships were obtained within ranges of (1-10 µg/band) and (2-10 µg/mL) for TLC-densitometry and HPLC, respectively. The obtained results were statistically compared with those of the official HPLC method and showed no significant difference with respect to their accuracy and precision at p = 0.05. Greenness scores represent excellent green analysis in comparison with the reported studies.

CONCLUSIONS

The proposed methods were validated according to ICH guidelines and were applied on bulk powder and pharmaceutical dosage form using eco-friendly mobile phases as the worldwide trend.

HIGHLIGHTS

Chromatographic methods have been validated for estimation of MDF in the presence of its degradation product. Clarification of degradation pathway and the elucidation of the structure were stated for the first time. It's the first published method using greenness assessment metrics for the analysis of MDF.

A microfabricated potentiometric sensor for metoclopramide determination utilizing a graphene nanocomposite transducer layer

In the recent drug analysis arena, optimizing a green, eco-friendly, and cost-effective technique is the main target. In order to cope with green analytical chemistry principles and the trending development of miniaturized portable and handheld devices, an innovative microfabricated ion-selective electrode for the analysis of metoclopramide (MTP) was developed. The fabricated electrode adopted a two-step optimization process. The first step of optimization depended on screening different ionophores in order to enhance the sensor selectivity. Calix-4-arene showed the maximal selectivity towards MTP. The second step was utilizing a graphene nanocomposite as an ion-to-electron transducer layer between the calix-4-arene polymeric membrane and the microfabricated copper solid-contact ion-selective electrode. The graphene nanocomposite layer added more stability to electrode potential drift and short response times (10 s), probably due to the hydrophobic behavior of the graphene nanocomposite, which precludes the formation of a water layer at the Cu electrode/polymeric membrane interface. The proposed MTP sensor has been characterized according to IUPAC recommendations and the linear dynamic range estimated to be 1 × 10^-6 to 1 × 10^-2 M with LOD of 3 × 10^-7 M. The proposed sensor has been successfully employed in the selective determination of MTP in bulk powder, pharmaceutical formulation, and biological fluid. No statistical significant difference was observed upon comparing the results with those of the official method. The Eco-score of the method was assessed using the Eco-Scale tool and was compared with that of the official method. Graphical abstract.