In situ microemulsion-gel obtained from bioadhesive hydroxypropyl methylcellulose films for transdermal administration of zidovudine.

This study aims to develop in situ microemulsion-gel (ME-Gel) obtained from hydroxypropyl methylcellulose (HPMC) films for transdermal administration of Zidovudine (AZT). Firstly, HPMC films containing propylene glycol (PG) and eucalyptus oil (EO) were obtained and characterized. Later, a pseudo-ternary phase diagram composed of water, EO, tween 80 and PG was obtained and one microemulsion (ME) with a similar proportion of the film components was obtained. ME was transformed in ME-Gel by the incorporation of HPMC. Finally, HPMC films were hydrated with Tween 80 solution to yield in situ ME-Gel and its effect on AZT skin permeation was compared with HPMC film hydrated with water (F5hyd). The results showed that the ME and ME-Gel presented a droplet size of 16.79 and 122.13 µm, respectively, polydispersity index (PDI) < 0.39 and pH between 5.10 and 5.40. The incorporation of HPMC resulted in viscosity about 2 times higher than the use of ME. The presence of AZT did not alter the formulation properties. The in situ ME-Gel promoted a two-fold increase in the permeated amount of AZT compared to F5hyd. The results suggest that it was possible to obtain an ME-Gel in situ from HPMC films and that its effect on transdermal permeation of AZT was significant.

Anti-inflammatory effect of nano-encapsulated nerolidol on zymosan-induced arthritis in mice.

Nerolidol is naturally occurring sesquiterpene has wide range of biological properties including anti-inflammatory activity. However, it has high volatility with low solubility in nature. The present study aimed to develop and characterized nano-encapsulated nerolidol and evaluated its activity on zymosan-induced arthritis model. Nano-capsules were produced by interfacial deposition of preformed polymer method and characterized by particle size, pH, polydispersity index (PDI), zeta potential, drug content and transmission electron microscopy (TEM). In vitro cytotoxicity of formulations was evaluated by alamar blue and MTT assays. In vivo neutrophils migration assay was performed on intra-articular zymosan-induced arthritis model in mice. Nano-encapsulated nerolidol suspensions presented adequate properties: mean diameter of particles 219.5 ±â€¯8.4 nm, pH: 6.84 ±â€¯0.5, PDI≤0.2, the zeta potential was -20.3 ±â€¯3.6 mV and drug content 71,2 ±â€¯1.3%. The formulations did not demonstrated cytotoxicity under the conditions assessed. Nerolidol 300 mg/kg inhibited neutrophils migration into joint cavity by 18.8% remains compared with control group, and nano-encapsulated nerolidol 3 mg/kg inhibited (26.7% remains) similar to free nerolidol 10 mg/kg (27.4% remains). Histological, quantification of pro-inflammatory and anti-inflammatory cytokines proves the same results. In conclusion the data suggests that nanoencapsulation of nerolidol improved its anti-inflammatory effect on arthritis in mice.