Nanoemulsions Containing a Coumarin-Rich Extract from Pterocaulon balansae (Asteraceae) for the Treatment of Ocular Acanthamoeba Keratitis

作者：Panatieri Lua Ferreira; Brazil Nathalya Tesch; Faber Kathrin; Medeiros Neves Bruna; von Poser Gilsane Lino; Rott Marilise Brittes; Zorzi Giovanni Konat; Teixeira Helder Ferreira^*

来源：AAPS PharmSciTech, 2017, 18(3): 721-728.

DOI：10.1208/s12249-016-0550-y

• Acanthamoeba
• coumarins
• nanoemulsion
• ocular keratitis
• Pterocaulon balansae

This study describes the incorporation of a coumarin-rich extract from Pterocaulon balansae into nanoemulsions intended for the local treatment of ocular keratitis caused by Acanthamoeba. The n-hexane dewaxed extract of P. balansae was characterized by HPLC/PDA and UPLC/MS. The presence of four major coumarins was detected, where 5-methoxy-6,7-methylenedioxycoumarin was selected as a chemical marker. This extract was then incorporated into nanoemulsions composed of medium chain triglycerides and egg-lecithin, through spontaneous emulsification. Such a procedure yielded the formation of monodisperse nanoemulsions in a sub-300-nm range, regardless of the amount of extract incorporated (1.0-5.0 mg/mL). The amoebicidal activity against Acanthamoeba castellanii was both dose-dependent and incubation time-dependent. A reduction of 95% of trophozoite viability was detected after 24 h of incubation with a nanoemulsion at 1.25 mg/mL of coumarins, being a similar effect detected for chlorhexidine. These results suggest a potential of the formulations developed in this study as a new strategy for the treatment of ocular keratitis caused by Acanthamoeba.

• 出版日期2017-4