THC morpholinylbutyrate (SP-111, Δ9-THC-O-[4-(morpholin-4-yl)butyrate]) is a synthetic derivative of
tetrahydrocannabinol, developed in the 1970s. It is a
prodrug which is converted into THC inside the body, and was one of the first derivatives of THC that is able to form water-
soluble salts, giving it a significant advantage over THC for some applications. However, it is less potent than THC and the metabolic conversion to THC is relatively slow and variable, giving it unpredictable
pharmacokinetics which has limited its research applications.[1][2][3][4]
^Dykstra LA, McMillan DE, Harris LS (1975). "Effects of delta-9-THC and a water soluble ester of delta-9-THC on schedule-controlled behavior". Pharmacology, Biochemistry, and Behavior. 3 (1): 29–32.
doi:
10.1016/0091-3057(75)90077-5.
PMID1129353.
S2CID140206443.
^Hershkowitz M, Szechtman H (November 1979). "Pretreatment with delta 1-tetrahydrocannabinol and psychoactive drugs: effects on uptake of biogenic amines and on behavior". European Journal of Pharmacology. 59 (3–4): 267–76.
doi:
10.1016/0014-2999(79)90290-5.
PMID230975.
^Järbe TU, McMillan DE (1980). "delta 9-THC as a discriminative stimulus in rats and pigeons: generalization to THC metabolites and SP-111". Psychopharmacology. 71 (3): 281–9.
doi:
10.1007/BF00433063.
PMID6256796.
S2CID11048922.