Presently, there are numerous structural classes of cannabinoid receptor agonists, all of which require solubilization for experimental purposes. One strategy for solubilizing water-insoluble tetrahydrocannabinols is conversion of the phenolic hydroxyl to a morpholinobutyryloxy substituent. The hydrochloride salts of these analogs are water-soluble and active in vivo when administered in saline. The present investigation demonstrated that hydrochloride salts of numerous substituted butyryloxy esters are water-soluble and highly potent. The substitutions include piperidine, piperazine, and alkyl-substituted amino moieties. It was also discovered that incorporation of a nitrogenous moiety in the alkyl side chain increased the pharmacological potency of tetrahydrocannabinol. For example, an analog containing a pyrazole in the side chain (O-2545) was found to have high affinity and efficacy at cannabinoid 1 (CB 1 ) and CB 2 receptors, and when dissolved in saline, it was highly efficacious when administered either intravenously or intracerebroventricularly to mice. A series of carboxamido and carboxylic acid amide analogs exhibited high pharmacological potency, but their hydrochloride salts were not water-soluble. On the other hand, incorporation of imidazoles into the terminus of the side chain led to water-soluble hydrochloride salts that were highly potent when administered in saline to laboratory animals. It is now possible to conduct cannabinoid research with agonists that are water-soluble and thus obviating the need of solubilizing agents.Marijuana has attracted considerable attention for centuries because of its psychotropic and medicinal properties. Early scientific investigations were conducted with either smoked plant material or the plant extract. Needless to say, the synthesis of marijuana's major psychotropic constituent, ⌬ 9 -THC, opened a new era in marijuana research (Gaoni and Mechoulam, 1964). For the first time researchers were able to conduct research in a quantitative fashion because the precise dose of ⌬ 9 -THC could be administered. Unfortunately, ⌬ 9 -THC is a noncrystalline, highly lipophilic compound that requires solubilization with either a surfactant agent or adherence to a water miscible substance (albumin, Tween 80, Emulphor, etc.). This high lipophilicity has placed constraints on the pharmacological evaluation of ⌬ 9 -THC. Even when dissolved in these vehicles, ⌬ 9 -THC has limited solubility and will precipitate if care is not exercised. This cannabinoid will adhere to solid surfaces rather than remain in solution under certain conditions. There is always the concern that the use of different vehicles in separate pharmacological studies may influence the pharmacological effects of ⌬ 9 -THC. Undoubtedly, these challenges in drug solubilization contribute to the vagaries accompanying cannabinoid data collection. Although many of the above vehicles are sufficient for systemic administration of cannabinoids, they present significant challenges for cannabinoid administration int...

No abstract

No abstract

The development of novel anti-inflammatory drugs (AID) has been claimed to be dependent on the discovery of models of inflammation that differ from those currently used for drug screening, e.g. carrageenen paw oedema and u.v. erythema. We have thus evaluated the effect of a variety of drugs in a number of novel models of inflammation in the rat produced in the hind paw. We have utilized kaolin, zymosan, anti-rat IgG (anti-IgG) and the Reversed Passive Arthus (RPA) reaction to produce these oedema models. We found that the non-steroidal AID's, e.g. aspirin, flufenamic acid, indomethacin, naproxen, and phenylbutazone, were active in all four tests. Of the nine novel AID examined, levamisole and tetramisole demonstrated considerable activity in all four tests and dapsone was especially active in the anti-IgG and RPA tests. In contrast, the anti-rheumatic d-penicillamine was inactive in all four models. Each of the ten compounds tested which has been claimed to influence complement function, was active in the RPA but not in the kaolin model. These results are discussed in the context of the aetiology of each oedema and the suspected mode of action of the various drugs.

A novel CB1 receptor agonist lead series was identified using a high-throughput screening approach. The initial screen afforded a single confirmed hit with poor water solubility. Structural variations were explored with the aim of introducing water solubility and improving potency. This led to the discovery of Org 28611, a potent, water soluble CB1 receptor agonist, which was selected for clinical evaluation as a potential intravenous analgesic agent.