The effects of two polymeric matrices for indomethacin in cutaneous nociceptive reactivity in mice

This paper is focused on the investigation the effects of two polymeric matrices for indomethacin in cutaneous pain models in mice. There were used two different co-polymers polyhydroxyethyl methacrylate and undecan, polymerization reactions being conducted under nitrogen, at 80 degrees C.

The experiments were carried out on white Swiss mice (20-25 g), divided into 6 groups of 7 animals each, treated orally. Biocompatibility properties of indomethacin-loaded copolymeric matrices ware evaluated by assessing the effects on the blood parameters, the serum biochemical tests of animals treated. The nociceptive somatic testing was performed using hot plate assay and tail immersion test. The latency (second) response to paw, respectively tail thermal noxious stimulation, was measured before the experiment and 15, 30, 60, 90, 120 minutes, 4, 6, 8, 10, 12 hours after the substances administration.

Laboratory analysis did not show significant differences of blood parameters, serum biochemical tests between control mice group (IND) and groups treated with 1 M, 1 IND, 3 M, 3 IND. In our experimental conditions IND determined a significant increasing of the latency period response, in hot plate and also in tail immersion tests. Using two different co-polymers for indomethacin incorporation we obtained an increasing of the latency time pain reaction in hot plate assay, respectively in tail immersion test, statistically significant (*p < 0.05) compared with the simple copolymers administration.

We demonstrated that indomethacin co-polymeric matrices 1 IND and 3 IND determined similar immune responses with indomethacin and simple co-polymers after oral administration in mice, indicative of good in vivo biocompatibility. Oral administration of both 1 IND and 3 IND resulted in prolonged antinociceptive effects in hot plate assay and also in tail immersion test in mice.