Development and evaluation of Classical and Pickering emulsions containing crude or fractionated extracts of Libidibia ferrea pods

Abstract

Objective: The development of medicinal plants for clinical use represents an important direction in biomedical research, despite the technological difficulties.

Significance: The aim of this study was to compare pharmaceutical characteristics and in vitro release of Classical and Pickering emulsions containing crude or fractionated extracts of Libidibia ferrea.

Methods: After evaluating the extract’s solubility in formulation, a dispersion of hydroxypropyl methylcellulose (HPMC) was prepared in water. For Pickering emulsions, the aqueous phase was HPMC and the oil phase was Miglyol^® 812; for Classical emulsions, water with Tween^® 20 and Miglyol^® 812 with Span^® 80 were used for aqueous and oil phases, respectively. Crude or fractionated extracts were added to the aqueous phase (5% w/v). Both phases were heated (40 °C); then, the oil phase was poured into the aqueous phase and homogenized using an Ultra-Turrax. Emulsions were characterized for 90 days by pH, polyphenol content, phytomarker content, macroscopic characteristics, droplet size, and zeta potential.

Results: These formulations displayed satisfactory stability for 90 days when stored at 25 °C. Regarding the investigation of rheological properties, Pickering emulsions displayed higher viscosity with lesser deformation than Classical emulsions. Moreover, the emulsions displayed similar in vitro release behavior.

Conclusion: Based on the results of present study, the Pickering emulsions were obtainable and displayed higher stability than Classical emulsions. Additionally, maintenance of system integrity points to promising systems for delivery of active pharmaceutical ingredients in the internal phase, despite the complex chemical mixture added to the external phase.

Keywords:

• Emulsion
• herbal extract
• in vitro release
• Libidibia ferrea
• Pickering

Disclosure statement

The authors report that they have no conflicts of interest.

Additional information

Funding

The authors are grateful for the financial support received from FACEPE [APQ-0493-4.03/14], CAPES, and DAAD (10453/14-8).