Pharmacokinetics of a New Analgesic on the Basis of Hexaazaisowurtzitane Derivative.

We studied pharmacokinetics of a new analgesic based on a hexaazaisowurtzitane derivative (thiowurtzine, TWZ). A method for measuring TWZ in organs and tissues by HPLC/MS/MS was developed and validated. The sensitivity of the method under conditions of intragastric administration of TWZ to rats in a dose of 100 mg/kg is 0.5 ng/ml (calibration curve 0.5-400 ng/ml). The concentrations of the substance (Cmax) in the plasma, organs, and tissues of animals were 20-100 ng/ml, the time to reach the maximum concentration after a single dose (Tmax) was 2 h. The mean retention time of the substance in the body ranged from 5.67 to 17.15 h after administration. The highest concentrations were found in excretory organs (liver and kidneys), the substance also actively penetrated into muscle tissue. The medium concentrations were found in the brain and adipose tissue. The tropism to the heart tissues was minimal.

Some Aspects of Investigation of the Central Mechanism of Antinociceptive Effect of a New Analgetic from the Hexaazaisowurtzitane Group.

Possible involvement of µ1- and κ-opioid receptors and cannabinoid type 1 receptors (CB1) into the mechanism of analgesic activity of the experimental drug product "Thiowurtzine, (capsule 120 mg)" synthesized on the basis of active pharmaceutical substance 4-(3,4-dibromthiophencarbonyl)-2,6,8,12-tetraacethyl-2,4,6,8,10,12hexaazatetracyclo [5,5,0,03,11,05,9]dodecane was studied in vivo using the hot plate test and acetic acid writhing test. The involvement of κ-opioid receptors and noninvolvement of µ1-receptors and CB1 receptors in the mechanism of thiowurtzine analgesia were demonstrated. The mechanism of interaction of the test analgesic with opioid receptors differs from that of the reference drug tramadol. The interaction of thiowurtzine with serotonergic, GABAergic, and muscarinic cholinergic neurotransmitter systems was studied in vivo using pharmacological analyzers. The absence of muscarinic cholinolytic effect of thiowurtzine was demonstrated in the model of arecoline-induced tremor. The central serotonin-blocking activity of the analgesic was revealed in the model of 5-hydroxytryptophan hyperkinesis in mice. Anticonvulsant activity was demonstrated in the corazol convulsions test, which attested to the presence of a GABAergic component. The mechanism of central analgesia caused by the drug product "Thiowurtzine, capsule 120 mg" appeared to be polymodal. The antinociceptive activity of the analgesic was comparable to that of tramadol.

Analgesic Activity of Hexaazaisowurtzitane Derivatives.

Pronounced analgesic activity of the innovative compound 4-(3,4-dibromthiophencarbonyl)-2,6,8,12-tetraacethyl-2,4,6,8,10,12hexaazatetracyclo[5,5,0,03, 11,05, 9] dodecane (thiowurtzine) was observed in the thermal nociceptive hot plate test and in the acute visceral and somatic deep pain model (acetic acid writhing test). In these experimental models, naloxone-sensitive thiowurtzine-induced analgesia was revealed. The absence of tropism to peripheral opioid receptors in the acetic acid writhing test was demonstrated using naloxone methiodide. Course administration of low-toxic thiowurtzine in effective doses was not associated with ulcerogenic damage to the gastric mucosa in experimental animals.