Semisolid formulations with therapeutic potential: development and stability study of cream and emulgel based on brazilian medicinal plants

Medicinal plants are a relevant source of bioactive compounds with potential applications in drug development. Species such as Pterodon pubescens Benth and Cordia verbenacea DC, native to Brazil, have shown anti-inflammatory and antinociceptive activities [ 1 ] [ 2 ] and synergistic effects when associated in formulations [ 3 ]. Thus, the aim of this project is to develop semisolid formulations (cream and emulgel) containing ethanol extract of P. pubescens (EEPP) and essential oil of C. verbenacea (EOCV) determining preliminary stability. The cream was prepared using a modified nonionic formulation from the Brazilian Pharmacopoeia [ 4 ], while the emulgel followed a previous study of Takayama et al. (2022), also with modifications [ 5 ]. Both formulations were made by heating the oily and aqueous phases to 75°C, then mixing them. Considering the emulgel, the gel phase containing Natrosol ®​ was incorporated into the emulsion after this step. EOCV and the EEPP were incorporated into the bases after cooling. Stability was assessed under three conditions: stability chamber (40°C±2°C, 70% humidity), refrigerator (5±2°C), and room temperature. Samples were analyzed for macroscopic appearance, centrifugation test, and pH over 15 days. Results indicated that the cream remained stable, with no phase separation, color or odor changes, and a pH variation of less than 10%, while in the emulgel formulation, phase separation was observed from the third day of analysis. Further studies are necessary to verify permeation and the in vivo efficacy, nevertheless, these findings provides a promising formulation for the treatment of inflammatory conditions. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany