Ultrasound-Assisted Extraction of Cannabinoids from Cannabis Sativa for Medicinal Purpose

Abstract

Over the past 20 years, the interest in Cannabis oily extracts for medicinal use compounded in pharmacy has consistently grown, along with the need to have preparations of adequate quality. Hot maceration (M) is the most frequently used method to compound oily solutions. In this work, we systematically studied the possibility of using an ultrasonic homogenizer and a sonotrode (US) as an alternative extraction method. Oily solutions were prepared using two available varieties of Cannabis for medicinal use, called FM2 and Bedrocan. All preparations resulted with an equivalent content in CBD and THC, with the advantage of a faster process using US. In particular, 10 min sonication at the amplitude optimized for the sonotrode used (2 or 7 mm) provides not statistically different total Δ9-tetrahydrocannabinol (M-FM2: 0.26 ± 0.02 % w/w; US-FM2: 0.19 ± 0.004 % w/w; M-Bedrocan: 1.83 ± 0.17 % w/w; US-Bedrocan: 1.98 ± 0.01 % w/w) and total cannabidiol (M-FM2: 0.59 ± 0.04 % w/w; US-FM2: 0.58 ± 0.01 % w/w) amounts extracted in refined olive oil. It can therefore be confirmed that sonotrode is an efficient and fast extraction technique and its use is without negative consequence on the solvent properties. Despite DSC evidencing that both maceration and sonication modify the T_onset and enthalpy of the event at about -10 °C, the qualitative characteristics of the oil remained constant for the two treatments and similar to the starting material.

Keywords: Bedrocan; DSC; FM2; lipophilic volatile carbonyl compounds; oil characterization; oxidized fatty acids; sonotrode; tocopherol.

Figure 1

Temperature variation of olive oil (red line) and silicone oil (black line) over time during maceration.

Figure 2

Variation of power (black line) and oil temperature (red line) upon UAE in 50 mL of olive oil using a 2 mm (solid line) or 7 mm (dashed line) probe.

Figure 3

DSC profiles of refined olive oil as raw material (black line) and after maceration for 40 min (red line) or UAE for 10 min using a 7 mm probe (blue line).