Evaluation of analgesic, antipyretic and anti-inflammatory activity of spirobarbitunylphenothiazines in rodents.

Analgesic, antipyretic and anti-inflammatory activities of newly synthesized spirobarbitunylphenothiazines viz 10-[7, 11-Di(4-4' dimethoxphenyl)-3-oxo-9-methylaminoimino-2, 4-diazaspiro [5.5] undecane 1, 5 dione] acetylphenothiazine (test drug A) and 10-[7, 11-Di (N.N-dimethylaminophenyl)-3-oxo-9-methylaminoimino-2, 4-diazaspiro [5, 5] undecane-1, 5 dione] acetylphenothiazine (test drug B) have been screened in Swiss mice and Wistar rats. The peripheral analgesic activity of test drugs A and B was investigated by acetic acid induced writhing test in Swiss mice while the central analgesic action was assessed by hot-wire (tail flick test) of the analgesiometer and tail-clip test in Wistar rats. Antipyretic activity was assessed on Brewer's yeast induced pyrexic model while antiinflammatory activity was seen on carrageenan induced hind paw oedema. Analgesic activity was found to be only of peripheral type as there was reduction of 66% in writhing responses by test drugs A and B in dose of 80 mg/kg in mice. No change in the tail flick responses was observed on analgesiometer or by tail clip by both the test drugs. Reduction of 1.5 to 2.0 degrees C in rectal temperature was observed in pyretic rats by test drugs A and B in dose of 80 mg/kg. 80% reduction in paw volume was noted in 80 mg/kg dose of both the test drugs which was comparable to the anti-inflammatory activity of 300 mg/kg, p.o. of phenylbutazone.