Smartphone based TLC approach versus conventional densitometric measurement for the simultaneous determination of donepezil and memantine, content uniformity testing along with greenness and whiteness assessment

Abstract

Thin layer chromatography (TLC) is a straightforward and economical technique that plays a major role in analytical field. Introducing the amenities of smartphones as accessible alternative detectors to TLC separation methods elaborates the cost-effectiveness of this technique and supports the appropriate assay of various aliphatic compounds after visualization by suitable reagents. Herein, two TLC coupled with smartphone's camera approaches are proposed for the assay of donepezil hydrochloride (DON) and memantine hydrochloride (MEM), a combined medication used in the management of Alzheimer's disease. Separation was achieved using a developing system of ethyl acetate, methanol, toluene, and ammonia (33%, w/v) in a ratio of 4:1:4:0.2, by volume. The dried plates were scanned at 190 nm for the densitometric assay, then visualized with modified Dragendorff's reagent and photographed by smartphone's camera. The data were integrated by displaying the photos in either ImageJ software or Color-Picker application. The findings produced from the three detection approaches were contrasted over concentration ranges of 1–18 & 4–28 μg/spot for the densitometric method, while the range was 1–20 & 1–30 μg/spot for the ImageJ method and 3–18 & 2–20 μg/spot for the Color-Picker method for DON and MEM, respectively. The methods were suitable for assaying both drugs in their pure form and combined pharmaceutical formulations. Densitometric and ImageJ-based methods were applied to evaluate the dosage forms content uniformity. The developed methods were assessed by three metric tools for greenness and sustainability, namely Green Analytical Procedure Index, Analytical GREEnness Metric Approach, and White Analytical Chemistry.