Drug preparation and delivery device
Salvinorin A was isolated from S. divinorum leaves and shown to be 99.5% pure by HPLC.
Because weighing the very small doses of salvinorin A required for this study is difficult, a larger quantity was weighed on an analytical balance and then dissolved in a measured volume of HPLC grade acetone. After filtering through a sterilized, acetone-approved 0.2 µm filter (Millex-LG Filter Unit, Millipore Corporation, Billerica, MA), 1 ml of solution was placed into a 5 ml round bottom chemistry flask and allowed to evaporate, leaving the dose of salvinorin A as a residue on the interior surface of the flask.
Before the session, the flask was attached to the bottom of a chemistry vacuum adapter by ground glass tapered joint and secured by a metal Keck clip. A vinyl tube (23 cm long, 6.35 mm inside diameter) was connected to the vacuum line of the adapter for inhalation. The tubing was replaced between participants but was not replaced for different sessions for the same participant. The resulting “pipe” was held stable by a ring stand clamp during administration, and the tube extended through a hole in a room divider toward the participant’s sitting area.
Drug administration
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For each session the round-bottom flask was heated from underneath with a butane microtorch with approximate flame temperature of 1700 ◦ C (model ST200T, Bernzomatic, Huntersville, NC). Although the boiling point and combustion temperature of salvinorin A have not been empirically determined, the flame temperature was assumed to be sufficient to heat the salvinorin A on the interior of the flask to its boiling point during the decreased air pressure created by inhalation, without substantial combustion of salvinorin A.
The microtorch was adjusted so that the flame was approximately 1.5 cm in length, and the tip of the flame was held in contact with the round-bottom flask. Using these procedures, inhalation of unvolatilized drug was unlikely because the salvinorin A residue left upon evaporation of acetone appeared strongly attached to the interior of the flask, and in tests with various rates of mechanical airflow (simulated inhalation) without heat, salvinorin A was observed to remain undisturbed. Tests with mechanical airflow and the application of the microtorch showed the method to result in the volatilization of salvinorin A with little scorching (small black marks presumably resulting from combustion).
Seated in a comfortable reclining lounger, the participant inhaled slowly for 40 s while the flask was heated, followed by a verbally cued exhale.
