Micronization of Thebaine Extracted from Papaver bracteatum Lindl. Using Supercritical Fluid Technology.

Background: Thebaine, as a main opiate alkaloid extracted from Papaveraceae plants, is widely used in the synthesis of many pharmaceutical ingredients such as buprenorphine, naltrexone, naloxone, and hydrocodone. Nevertheless, thebaine and related derivatives are often insoluble in aqueous media and have low bioavailability in digestive systems.

Objective: Reducing particle size and changing the morphology can mitigate the mentioned problem. In this study, extraction of thebaine from the capsule, stem, and root of Papaver bracteatum L. was optimized and micronization of extract components was developed to study solubility.

Methods: The extraction process was performed using supercritical carbon dioxide. Experimental central composite design was employed to determine the optimal conditions. Analysis of extract was done using a validated high performance liquid chromatography method and mass spectrometry. The micronization process was performed using an inhouse developed supercritical technique. The nanoparticles were characterized using field emission scanning electron microscopy (FESEM) and ImageJ software. The effect of micronization was explored on the solubility of extract components via ultraviolet spectroscopy.

Results: The percentage of thebaine in dried capsule, stem, and root powder was about 1.05, 0.31, and 0.83% respectively. The extraction results indicate that supercritical pressure has the greatest effect on the extraction yield. Analysis of FESEM images revealed that nanoparticles of extract components with particle size distribution of 5-100 nm were collected successfully.

Conclusion: The extraction results indicate that pressure has the greatest effect on the extraction yield. In vitro studies illustrated that the solubility of extract components increased up to 1.7 times during the micronization process.

Highlights: Expansion of supercritical methods as an effective method was performed for extracting and preparing alkaloid nanoparticles. This process led to improved oral bioavailability of alkaloids.