p,p'-Methoxyl-diphenyl diselenide-loaded polymeric nanocapsules as a novel approach to inflammatory pain treatment: Behavioral, biochemistry and molecular evidence.

The current study investigated the effect of organoselenium compound p,p'-methoxyl-diphenyl diselenide [(OMePhSe)2], free or incorporated into nanocapsules, on behavioral, biochemical and molecular alterations in an inflammatory pain model induced by complete Freund's adjuvant (CFA). Male Swiss mice received an intraplantar injection of CFA in the hindpaw and 24 h later they were treated via the intragastric route with a single (OMePhSe)2 administration, in its free form (dissolved in canola oil) or (OMePhSe)2 NC. The anti-hypernociceptive time- and dose-response curves were carried out using the von Frey hair test. Biochemical and histological parameters were determined in samples of injected paws and those of cerebral contralateral cortex were collected to determine immuno content of inflammatory proteins. Both (OMePhSe)2 forms reduced the hypernociception induced by CFA as well as attenuated the altered parameters of the inflammatory process in the paw (paw edema, myeloperoxidase and histological). However, the (OMePhSe)2 NC had a more prolonged anti-hypernociceptive action (7h) at a lower dose (10mg/kg) and superior effects on the paw alterations than the free compound form (4h and 25mg/kg). Furthermore, independent of the (OMePhSe)2 form, its administration decreased the MAPKs pathway activation (JNK;ERK1,2; p38) as well as iNOS, COX-2, Nf-κB and IL-1ß protein contents in the cerebral contralateral cortex that were increased by paw CFA injection. Therefore, (OMePhSe)2 NC had superior anti-inflammatory action, which possibly occurs by the inflammatory protein content modulation and also attenuates paw biochemical and histological inflammatory alterations induced by CFA injection.

Pomegranate seed oil nanoemulsions improve the photostability and in vivo antinociceptive effect of a non-steroidal anti-inflammatory drug.

The combination of pomegranate seed oil and ketoprofen in nanoemulsions aiming to improve the antinociceptive effect was evaluated according to the writhing test and Complete Freud's Adjuvant induced paw inflammation in mice. The formulations showed adequate characteristics and improved ketoprofen's photostability against UVC radiation exposure. The dialysis bag technique showed that 100% of the drug was released from the nanoemulsions after 3h and the oil amount had no influence on the releasing. Furthermore, time- and dose-response curves were obtained to determine the antinociceptive effect of the formulations. In the post-test, the nanoemulsion containing ketoprofen significantly reduced abdominal constrictions in time-response curve, showing effect up to 12h while the free ketoprofen showed effect up to 3h. In addition, the blank nanoemulsion presented a reduction of abdominal constriction up to 1h of pre-treatment. Regarding the dose-response curve, the free ketoprofen presents effect at 0.5mg/Kg dose and nanoemulsion at 1.0mg/Kg dose. Time- and dose-response curves were performed to determine the antinociceptive effect in inflammatory pain. After the evaluation of mechanical allodynia testing at the Von Frey Hair, the free ketoprofen showed effect up to 6h while nanoemulsions presented effect up to 10h. Moreover, acute toxicity was performed with ALT and AST activity evaluations and urea levels. After 7 days of treatment, no toxic effects for nanoemulsions were found. In conclusion, ketoprofen-loaded pomegranate seed oil nanoemulsions presented adequate characteristics and a high antinociceptive activity in the animal models tested.