Pharmacology of orally administered Δ⁹‐tetrahydrocannabinol

Abstract

A systematic study of the oral administration of 35 mg. of Δ 9 ‐tetrahydrocannabinol (Δ 9 ‐THC) in 5 different vehicles indicates that the speed and degree of absorption are greatly influenced by the vehicle. When the same vehicle was used, absorption of the drug varied significantly among individuals. The psychologic effects were characterized by a marihuana‐like “high” qualified by experienced sub;ects to be more intense than that associated with smoked marihuana or hashish. Predominant physiologic effects were congestion of the conjunctiva, tachycardia, and moderate increases in blood pressure. Hypotention with bradycardia occurred when the blood pressure control was challenged by a change in posture or blood volume. The biologic half‐life of the drug appears to be less than 48 hours. Thin‐layer chromatographic analysis indicates that the metabolites in the plasma are the 11‐OH‐Δ 9 ‐THC, an unknown compound, the 8,11‐di‐OH‐Δ 9 ‐THC, and a group of more polar substances located at the origin. Δ 9 ‐THC and its metabolites are excreted extensively in the urine and feces. The maior urinary metabolites are the 8,1l‐di‐OH‐Δ 9 ‐THC and polar substances where cannabinoid acids predominate. Appreciable amounts of Δ 9 ‐THC are found in feces.