Marathur Rodhiyah, William Xaveriano Waresindo, Halida Rahmi Luthfianti, Kusjuriansah, Nabila Asy Syifa, Dhewa Edikresnha, Dian Ahmad Hapidin, Tri Suciati, Akfiny Hasdi Aimon, Khairurrijal Khairurrijal
In this study, the freeze-thaw method has been successfully used to fabricate polyvinyl alcohol (PVA) hydrogel loaded with bandotan leaves extract (BLE). The precursor solutions for hydrogel were prepared by stirring PVA solution and BLE solutions at the ratio of 10:0, 10:1, 10:2, 10:3, 10:4, and 10:5. The concentration of PVA was 12% w/w in water, while the BLE solution was 5% w/w in a solvent mixture of water/ethanol, at a weight ratio of 1:1. The freezing and thawing temperature was maintained at -25°C for 20 hours and at 37°C for 4 hours, respectively. The increasing concentration of BLE in the precursor solutions led a reduction in viscosity, density, and pH value. The obtained pH levels ranged from 4.7 to 5.9, a range deemed compatible with human skin. The swelling degree of the composite hydrogels initially increased along the increase fraction of BLE. However, it subsequently diminished as the BLE fraction became excessively high. Notably, the hydrogel with a PVA/BLE ratio of 10:2 manifested the most substantial swelling degree. The swelling degree result was best modeled after the second-order swelling kinetics. The release of BLE during the swelling degree test was also confirmed by the weight loss test. The mechanical properties of the as-formed hydrogels, including fracture stress, onset strain, and onset stress, displayed a diminishing trend with increasing BLE concentration in the precursor solutions. This reduction in mechanical strength can be attributed to the higher percentage of ethanol incorporated within the hydrogel due to the high BLE fraction. The presence of ethanol within the hydrogel contributed to a softer texture, because the ethanol inside the hydrogel acted as the free liquid and did not freeze throughout the freeze-thaw process. © 2025 American Institute of Physics Inc.. All rights reserved.
Department of Physics, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung, 40132, Indonesia; University Center of Excellence-Nutraceutical, Bioscinece, Biotechnology Research Center, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung, 40132, Indonesia; Department of Pharmaceutics, School of Pharmacy, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung, 40132, Indonesia; Department of Physics, Faculty of Science, Institut Teknologi Sumatera, Jl. Terusan Ryacudu, Lampung, 35365, Indonesia