Optimization and Validation of TLC Densitometry Method for 6-Gingerol Analysis in Orally Disintegrating Films of Zingiber officinale var. rubrum Extract

Red ginger (Zingiber officinale var. rubrum) is a medicinal plant in Indonesia that is empirically known to have antiemetic, antioxidant, anti-inflammatory, and analgesic properties. Orally Disintegrating Films (ODF) offer advantages like ease of administration, rapid disintegration, and improved patient compliance. This study aimed to formulate red ginger rhizome extract into ODF and to determine its marker compound, 6-gingerol, using an optimized and validated TLC–densitometry method. The formulated ODF using the solvent casting method met all evaluation criteria, including organoleptic characteristics, uniformity of weight and thickness, and disintegration time. Thin layer chromatography-densitometry method utilized silica gel 60 F254 and an optimized mobile phase of n-hexane:ethyl acetate (7:3). The chromatographic parameters showed an Rf value of 0.29 ± 0.05, resolution of 2.308, tailing factor of 1.0, number of theoretical plates of 13,456, and HETP of 0.0005945. Method validation at 281 nm demonstrated excellent linearity (r = 0.99974), with detection and quantification limits of 13.94 and 42.25 µg/mL, respectively. The method met the precision requirement, yielding intraday precision of 1.03–1.83% and interday precision of 0.73–1.43%, alongside acceptable accuracy, with recovery rates of 98.21–100.80% for the extract and 98.47–100.80% for the ODF. The amount of 6-gingerol was found to be 0.54% in the raw extract and 0.50% in the ODF formulation. The results showed that the TLC–densitometry method obtained is both valid and dependable for measuring the amount of 6-gingerol in red ginger extract ODF preparations.