Preparation of ligustrazine microemulsion and comparative study on in vitro release of different size microemulsions / 中草药

ABSTRACT

Objective: To study the preparation process of ligustrazine microemulsion delivery system and evaluate its physical pharmacy properties; Microemulsions of different particle sizes were prepared in different oil phases, and the effect of particle size factors on the release behavior of the preparation was investigated. Methods: Taking the solubility of ligustrazine as index, the oil phase, emulsifier, and co-emulsifier were screened. The microemulsion formulation was optimized by pseudo-ternary phase diagram method. The encapsulation efficiency and drug loading was studied by ultrafiltration centrifugation. The particle size and potential were detected by the particle size analyzer. The release behavior of microemulsions with different particle sizes was compared by dialysis bag method. Results: The tetramethylpyrazine microemulsion was successfully prepared, and the appearance was clear and transparent. The average pH value was about 5.46. The detection method of microemulsion encapsulation rate was successfully established. When the drug loading of ligustrazine was 1.2 mg/mL, the encapsulation efficiency was (87.43 ± 0.20)%. The microemulsions of different particle sizes were prepared by changing the oil phase (ethyl oleate, oleic acid, and IPM). When the drug loading was 1.2 mg/mL, the three particle sizes were (16.80 ± 0.91), (129.50 ± 1.21), and (18.51 ± 0.24) nm, respectively. The release test showed that the release rate of all three could reach more than 90% within 4 h, and there was no significant difference. Conclusion: The uniform and stable tetramethylpyrazine microemulsion is successfully prepared; The release behavior of different tetramethylpyrazine microemulsions is not affected by the particle size factor.