Cluster analysis of fingerroot cultivated in different regions across Thailand and implementation of Quality by Design approach for R&D of fingerroot extract tablet.

Fingerroot has been used as food, traditional medicine, and a dietary supplement. This study aimed to cluster fingerroot cultivated in different regions across Thailand, based on their flavonoids. Subsequently, the extract of fingerroot was formulated into tablet form using a Quality by Design (QbD) approach. Initially, 32 fingerroot samples were included in this study. They were analyzed using a validated high-performance liquid chromatographic method. The results indicated that the rhizomes of fingerroot had higher flavonoid content (pinocembrin, pinostrobin, and panduratin A) compared to the roots. Cluster analysis revealed that fingerroot from Surat Thani, Nong Bua Lamphu, Kalasin, and Sisaket Provinces formed a high flavonoid content group. Ethanolic extract of defatted fingerroot from Sisaket Province was then used to prepare tablets. Following the QbD approach, the quality target product profile, critical quality attributes, initial risk assessment, and formulation design were investigated. A Box-Behnken design was applied to optimize the tablet formulation. Design spaces were constructed, and the optimal formulation was verified. The optimal formulation comprised 3 % hydroxypropyl methylcellulose F4M without spray-dried lactose, compressed using 1,000 psi force. The tablets had an individual weight of 600 mg, a thickness of 4.22 mm, a diameter of 12.6 mm, a hardness of 6.33 kP, a disintegration time of 2.02 min, and a friability of 0.05 %. Each tablet contained 120 mg of fingerroot extract, consisting of 9.77 mg pinocembrin, 23.00 mg pinostrobin, and 11.27 mg panduratin A. Dissolution tests demonstrated that the three flavonoids could dissolve in a 0.5 % sodium lauryl sulfate solution at levels of 99.34 %, 103.81 %, and 61.44 % within 2 h, which was superior to a commercial product. In summary, this study provides a guide for selecting fingerroot cultivated in Thailand with high flavonoid content. Furthermore, the QbD approach was successfully implemented in the development of a fingerroot extract tablet with desired properties.