Study on prescription process of nanoemulsion of Perilla frutescens essential oil and preliminary quality evaluation / 中草药

ABSTRACT

Objective: Using Perilla frutescens as a model drug, the nanoemulsion of Perilla frutescens essential oil (PFEO) were prepared, and the formulation process research and preliminary quality evaluation were carried out. Methods: The cosurfactants were determined according to the amount of PFEO dissolved in various excipients. The HLB value method was used to preliminarily screen surfactants suitable for oil-in-water (O/W) nanoemulsions, and the surfactants with dosage safety were further screened to determine the composition of nanoemulsion formulations. By drawing a pseudo-ternary phase diagram, the nanoemulsion region size, drug loading, water content, and conductivity, viscosity, particle size, distribution, and stability was comprehensively compared to optimize the prescription. This study investigated the appearance, physicochemical properties (viscosity, pH value, conductivity, electrical conductivity, particle size, Zeta potential), stability, in vitro permeability properties and nasal mucosa irritation of the nanoemulsion of PFEO. Results: The final optimized nanoemulsion formulation was 14.3% PFEO-9.5% Transcutol P-19.1% Labrasol-57.1% water. The nanoemulsion of PFEO prepared according to the optimized prescription was uniform, transparent, clear, with good fluidity. The viscosity was (3.68 ± 0.17) mPa∙s, pH value was (6.18 ± 0.03), the electrical conductivity was (109.61 ± 0.89) μS/cm, the Zeta potential was (-7.08 ± 1.82) mV, and the particle size was (49.98 ± 1.55) nm. The results of transmission electron microscope experiment showed that, the droplets of PFEO nanoemulsion were spherical with the particle size within 100 nm. The stability test results showed that the nanoemulsion of PFEO had centrifugal stability, dilution stability, long-term stability and temperature stability. After storage at room temperature and unsealed for one month and six months, the percentage change of the average perillaldehyde content of PFEO nanoemulsion and PFEO was 1.8% and 17.48%, respectively. The nasal mucosal irritation test results showed that the PFEO nanoemulsion administration group had no significant difference from the blank saline group. Conclusion: The appearance and related physical and chemical properties of PFEO nanoemulsion prepared by optimized prescription process meet the quality requirements of nanoemulsion, with drug stability, drug permeability and safety.