PMIO 2017; 4(03): e82-e88
DOI: 10.1055/s-0043-119759
Original Papers
Georg Thieme Verlag KG Stuttgart · New York

Nanoemulsion Improves Antinociceptive Activity of HP1, a Benzopyran from Hypericum polyanthemum

Gabriela Meirelles1, Henrique Bridi1, Eveline Dischkaln Stolz1, Helder Ferreira Teixeira1, Gilsane Lino von Poser1, Stela Maris Kuze Rates1
  • 1Pharmaceutical Sciences Postgraduate Program, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
Further Information

Publication History

received 10 April 2017
revised 31 July 2017

accepted 04 September 2017

Publication Date:
09 October 2017 (online)


The impact of nanoemulsification on the antinociceptive effect of benzopyran HP1 in a mice hot plate test was investigated. For comparison, the same experiments were performed with HP1-free form. The durability of the antinociceptive effect was analyzed at 60, 120 and 180 min. The results revealed that HP1 was successfully incorporated into a nanoemulsion system, given its high solubility in the oil phase. Regarding the pharmacological effect, HP1 (15, 30, 45, and 60 mg/kg, p.o.), both forms, displayed the pattern of a bell-shaped dose-response curve. HP1-loaded nanoemulsion displayed the maximal antinociceptive effect at a lower dose than the HP1-free form. The highest effect of the free compound was observed at 45 mg/kg, while the HP1-loaded nanoemulsion displayed the same effect at 30 mg/kg. These results suggest that the observed effect might be attributable to an increase in solubility and, thus, the enhancement of compound absorption. Regarding the durability of the antinociceptive effect, the outcomes demonstrated that the HP1-free form lost its antinociceptive effect at 120 min, while the HP1-loaded nanoemulsion kept its effect until 180 min. These findings corroborate literature data, where studies have demonstrated absorption enhancement when a compound was loaded in a nanoemulsion system.

Supporting Information