Recent progress in cannabinoid research

Preparation and characterization of inclusion complexes of a hemisuccinate ester prodrug of delta9-tetrahydrocannabinol with modified beta-cyclodextrins

Delta(9)-Tetrahydrocannabinol hemisuccinate (THC-HS), an ester prodrug of Delta(9)-tetrahydrocannabinol (THC) has been investigated for its potential to form inclusion complexes with modified synthetic beta-cyclodextrins (CDs). Phase solubility studies were performed to determine the stoichiometric ratio of complexation of THC-HS with random methylated beta-cyclodextrin (RAMEB) and 2-hydroxypropyl beta-cyclodextrin (HPBCD). THC-HS/RAMEB and THC-HS/HPBCD solid systems were prepared by lyophilization and the lyophilized complexes were characterized by Fourier transform infrared (FT-IR) spectroscopy, proton nuclear magnetic spectroscopy, and molecular modeling techniques. The formation of inclusion complexes of THC-HS/RAMEB and THC-HS/HPBCD was demonstrated by an A(L) type curve with the slopes less than unity by the phase solubility method. The association constants for THC-HS/RAMEB and THC-HS/HPBCD were found to be 562.48 and 238.83 M(-1), respectively. The stoichiometry of both of the complexes was found to be 1:1 as determined from the Job's plot. This was confirmed by (1)H NMR and FT-IR techniques. The results obtained from the molecular modeling studies were in accordance with the data obtained from nuclear magnetic resonance and FT-IR. The docking studies revealed the most probable mode of binding of THC-HS with RAMEB in which the alkyl chain was submerged in the hydrophobic pocket of the CD molecule and hydrogen bonding interactions were observed between the hemisuccinate ester side chain of THC-HS and the rim hydroxy groups of RAMEB. The solubility of THC-HS was significantly higher in RAMEB compared to HPBCD. Solid dispersions of THC-HS with CDs will be further utilized to develop oral formulations of THC-HS with enhanced bioavailability.

Synthesis and pharmacological evaluation of analogs of indole-based cannabimimetic agents

Aminoalkylindoles (AAIs), although structurally dissimilar from the classical cannabinoids, are known to be capable of binding to cannabinoid receptors and of evoking cannabinomimetic responses. With the aim of investigating the structure-activity relationships (SAR) for the binding of non-classical agonists to CB1 and CB2 cannabinoid receptors, we designed and synthesized a series of indole derivatives. The compounds were tested for their analgesic action by formalin test and compared to WIN 55212-2, an AAI acting to the cannabinoid receptors. In receptor binding assay, compound 5 showed affinity for the CB1 receptor comparable to WIN 55212-2.