Pengaruh Konsentrasi Gel Lidah Buaya terhadap Laju Difusi Methylene Blue pada Media Agar

Abstract

This study evaluated the effect of Aloe vera gel concentration on the diffusion rate of methylene blue in agar medium. The research used a laboratory experimental design with three agar formulations: F0 without Aloe vera gel, F1 containing 5% Aloe vera gel, and F2 containing 10% Aloe vera gel. Each formulation contained 2 g agar and was adjusted to 100 mL with aquadest. Methylene blue was placed into a central diffusion well, and the diffusion diameter was observed at 5, 10, 15, 20, 30, and 40 minutes. The final diffusion diameter decreased from 0.04 cm in F0 to 0.02 cm in F1 and 0.01 cm in F2. The calculated diffusion rates were 0.0100, 0.0050, and 0.0025 cm/minute, respectively. These findings indicate that increasing Aloe vera gel concentration reduces methylene blue diffusion in agar, most likely due to increased medium viscosity and greater resistance to molecular movement. The study supports the relevance of gel viscosity control in semisolid pharmaceutical formulation development.