Effect of ultrafine comminution on transdermal absorption and rheology of Polygonum cuspidatum ointment / 中草药

ABSTRACT

Objective: To study the effect of ultrafine comminution on transdermal absorption and rheology of P. cuspidatum ointment (PCO). Methods: Common and ultrafine common powder of P. cuspidatum was got by common and ultrafine comminution technology respectively, and then prepared into common and ultrafine PCO. The skin permeation of common and ultrafine PCO was investigated through in vitro excised mice skin using improved Franz diffusion cell, with polydatin, resveratrol, and emodind as the indexes to compare the effect on the cumulative permeation amount and permeation rate of ointments. Then the effect on the rheology of ointments with apparent viscosity and yield stress as the indexes was compared. Results: The d0.9 of common and ultrafine powder of P. cuspidatum were (210.011 ± 3.468) and (63.496 ± 2.570) μm; And the spans were (5.412 ± 0.055) and (2.913 ± 0.117), respectively. The cumulative permeation amount of polydatin, resveratrol, and emodind of PCO were (2.100 3 ± 0.154 5), (2.114 5 ± 0.341 6), and (6.210 4 ± 0.750 0) μg/cm2, and the permeation rate were (0.175 3 ± 0.022 6), (0.234 0 ± 0.020 2), and (0.337 4 ± 0.051 6) μg/(cm2∙h), respectively. The ultrafine cumulative permeation amounts of polydatin, resveratrol, and emodind of PCO were (14.247 9 ± 4.875 0), (4.399 3 ± 0.628 7), and (6.768 6 ± 0.728 6) μg/cm2, which were 6.8, 2.1, and 1.1 times compared to common PCO; The permeation rates were (0.815 9 ± 0.277 1), (0.313 2 ± 0.043 0), and (0.393 7 ± 0.042 6) μg/(cm2∙h), which were 4.7, 1.3, and 1.2 times compared to common PCO respectively. The cumulative permeation amounts and permeation rates of ultrafine PCO were 6.8, 2.1, 1.1 and 4.7, 1.3, 1.2 times compared to common PCO. The apparent viscosity and yield stress of common and ultrafine PCO were 34.940, 8.865 Pa∙s and 41.211, 7.381 Pa. Conclusion: Compared with common PCO, the transdermal permeability and fineness of ultrafine PCO were improved, and the apparent viscosity and yield stress decreased, which facilitates of spreadability.