Dermatopharmacokinetic and pharmacodynamic evaluation of a novel nanostructured formulation containing capsaicinoids for treating neuropathic pain.

The in vivo skin penetration by dermal microdialysis and the pharmacological efficacy of a chitosan hydrogel containing capsaicinoids-loaded nanocapsules (CHNCCaps) was evaluated in this study. Such gel has previously been proven to control capsaicinoids release and decrease the drugs side effects in humans. The nanocapsules containing capsaicinoids had an average size around 150 nm, with a low polydispersity index, positive zeta potential, and high encapsulation efficiency of the drugs. The CHNCCaps showed intact nanocapsules, a slightly acid pH value, and a pseudoplastic behavior suitable for topical application. Microdialysis experiments showed a 1.6-fold increase in the concentration of capsaicinoids in the dermis (after 12 h of its application) when CHNCCaps was administered compared to a chitosan hydrogel containing capsaicinoids in hydroethanolic solution (CHETCaps) and the commercial cream. The CHNCCaps showed antiallodynic and antihyperalgesic effects from 6 h to 96 h after treatment initiation, whereas CHETCaps and the commercial cream showed antiallodynic and antihyperalgesic effects only at 48 h and 96 h after treatment initiation, respectively. CHNCCaps and the commercial cream maintained antihyperalgesic activity for 6 days after treatment interruption. For mechanical allodynia, the antinociceptive effect was maintained for 48 h after treatment interruption only with CHNCCaps. In conclusion, CHNCCaps is a promising formulation for treating peripheral neuropathic pain.

Anti-atherogenic effects of a new thienylacylhydrazone derivative, LASSBio-788, in rats fed a hypercholesterolemic diet.

The compound LASSBio-788 (N-Allyl (2-thienylidene) 3,4-methylenedioxybenzoylhydrazine) is a thienylacylhydrazone derivative shown to have antiplatelet, vasodilatory, and anti-inflammatory properties in vitro. We hypothesize that LASSBio-788 may exert beneficial effects on atherosclerosis. Male wistar rats were divided into 4 groups: Control group received standard rat chow, hypercholesterolemic group (HC) and HC+788 (compound LASSBio-788 group) received hypercholesterolemic diet for 45 days. HC+788 group received compound LASSBio-788 (100 µmol/kg) once daily in the last 15 days. LASSBio-788 reduced the levels of total cholesterol (109.1 ± 4.3 vs. 361.0 ± 12.8 mg/dl), triglycerides (66.1 ± 1.1 vs. 186.9 ± 17.7 mg/dl), LDLc (63.2 ± 6.1 vs. 330.9 ± 9.7 mg/dl), VLDLc (9.8 ± 1.1 vs. 45.0 ± 4.6 mg/dl) and malondialdehyde (4.8 ± 0.3 vs. 9.4 ± 0.5 nmol/ml) compared to the HC group. LASSBio-788 presented antiplatelet properties and decreased inflammatory markers levels. LASSBio-788 promoted a decrease in contractile response to phenylephrine and an improvement in endothelium-dependent vasorelaxant response by increasing two-fold the expression of nitric oxide synthase (eNOS). Our results suggest that the compound LASSBio-788 represents a new multi-targeted drug candidate for the treatment of atherosclerosis.

Docking, synthesis and pharmacological activity of novel urea-derivatives designed as p38 MAPK inhibitors.

p38 mitogen-activated protein kinase (p38 MAPK) is an important signal transducing enzyme involved in many cellular regulations, including signaling pathways, pain and inflammation. Several p38 MAPK inhibitors have been developed as drug candidates to treatment of autoimmune disorders, such as rheumatoid arthritis. In this paper we reported the docking, synthesis and pharmacological activity of novel urea-derivatives (4a-e) designed as p38 MAPK inhibitors. These derivatives presented good theoretical affinity to the target p38 MAPK, standing out compound 4e (LASSBio-998), which showed a better score value compared to the prototype GK-00687. This compound was able to reduce in vitro TNF-α production and was orally active in a hypernociceptive murine model sensible to p38 MAPK inhibitors. Otherwise, compound 4e presented a dose-dependent analgesic effect in a model of antigen (mBSA)-induced arthritis and anti-inflammatory profile in carrageenan induced paw edema, indicating its potential as a new antiarthritis prototype.

Antinociceptive profile of 2,3,6-trisubstituted piperidine alkaloids: 3-O-acetyl-spectaline and semi-synthetic derivatives of (-)-spectaline.

In early studies, we have reported the antinociceptive profile of (-)-spectaline, a piperidine alkaloid from Cassia spectabilis. The present study describes the synthesis, the antinociceptive and anti-inflammatory activities of a series of 2,3,6-trialkyl-piperidine alkaloids: the natural (-)-3-O-acetyl-spectaline (LASSBio-755) and ten semi-synthetic spectaline derivatives. Structure-activity relationship (SARs) studies were performed. The structures of all synthesized derivatives were confirmed by means of nuclear magnetic resonance. Compounds were evaluated for their analgesic (acetic acid-induced mouse abdominal constrictions, hot-plate test, formalin-induced pain test) and some of them for the anti-inflammatory activities (carrageenan-induced rat paw edema test). The pharmacological results showed that several of the new compounds given orally at a dose of 100 micromol/kg significantly inhibited the acetic acid-induced abdominal constrictions, but they were less active than (-)-spectaline. LASSBio-755 and LASSBio-776 were the most actives with 37% and 31.7% of inhibition. In the formalin-induced pain only LASSBio-776 was able to inhibit by 34.4% the paw licking response of the inflammatory phase, (-)-spectaline and LASSBio-755 did show any activity. In the carrageenan-induced rat paw edema, only (-)-spectaline exhibited an anti-inflammatory profile, showing an ED(50) value of 56.6 micromol/kg. Our results suggest different mechanisms of action for the analgesic activity observed for LASSBio-776 (3-O-Boc-spectaline), LASSBio-755 (3-O-acetyl-spectaline) and (-)-spectaline (LASSBio-754). The antinociceptive profile of some of the semi-synthetic spectaline derivatives extends our research concerning the chemical and pharmacological optimization of isolated natural products in the search of new drug candidates from Brazilian biodiversity.