Characterization and Preclinical Toxicity Assessment of Intranasal Administration of Standardized Extract of <i>Centella asiatica</i> (L.) Urban Leaves (INDCA-NS) in Laboratory Rats

Abstract

The objective of the present work was to characterize and assess the intranasal toxicity of a solution of total triterpenoids - based standardized extract of Centella asiatica (L.) Urban leaves (INDCA-NS). The acute and 28-day repeated-dose toxicity of intranasal administrated INDCA-NS in Wistar rats was evaluated. For the acute intranasal toxicity study, a single dose of 100 μg/rat/day was administered to five male and female rats and observed for mortality and signs of toxicity for 14 days. In the subacute toxicity study, the INDCA-NS (10, 30, and 100 μg/rat/day) were intranasally administered to a separate group of five male and female rats for 28 days, followed by a 14-day reversal period for behavioral, biochemical, and histological parameters. The effect of subacute administration of INDCA-NS on the ability to smell in rats was evaluated by a buried food test. Treatment with INDCA-NS did not result in mortality or treatment-related adverse signs during single or 28-day repeated-dose administration. In addition, intranasal INDCA-NS did not affect the sense of smell, as observed in the buried food test. Intranasal NDCA-NS was found safe in rats with a Maximum Tolerated Dose (MTD) of more than 100 μg/rat/day and No-Observed Adverse Effect Level (NOAEL) of more than 100 μg/rat/day in male and female rats during acute and subacute intranasal toxicity study respectively.