The role of light anhydrous silicic acid on physical stability of troglitazone solid dispersion under humidified conditions

•Aerosil exhibited a stabilizing effect on solid dispersion under humid conditions.•The stabilizing effect could not be predicted based on the evaluation of Tg.•Hydrophobic Aerosil stabilized solid dispersion stronger than hydrophilic Aerosil.•The stabilizing mechanism was speculated based on the comparative results.

The aim of this study was to confirm whether light anhydrous silicic acid (Aerosil) could exhibit a stabilizing effect on the physical stability of solid dispersion under humidified conditions. Ternary solid dispersions consist of 50% troglitazone, and various ratios of polyvinyl pyrrolidone and Aerosil were prepared using the co-milling method and then evaluated for their crystallizing behavior under storage conditions. The results showed that Aerosil has a stabilizing effect against crystallizing in the dihydrate of troglitazone under humidified conditions and has an appropriate ratio range (Troglitazone/PVP/Aerosil = 50/30–20/20–30) in the ternary solid dispersion, when considering total quality satisfaction such as physical stability and dissolution. Furthermore, it was found that hydrophobized Aerosil R805 has a stronger stabilizing effect than hydrophilic Aerosil 200. The stabilizing mechanism was discussed based on the comparative results and possible molecular interaction.

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