Hydrogel containing dexamethasone-loaded nanocapsules for cutaneous administration: preparation, characterization, and in vitro drug release study

Abstract

Context: Our group previously reported the development of dexamethasone-loaded polymeric nanocapsules as an alternative for topical dermatological treatments. Objective: Our study aimed to prepare and characterize a hydrogel containing this system to improve the effectiveness of the glucocorticoid for cutaneous disorders. Methods: For the antiproliferative activity assay, a dexamethasone solution and D-NC were tested on Allium cepa root meristem model. D-NC were prepared by the interfacial deposition of preformed polymer. Hydrogels were prepared using Carbopol Ultrez® 10 NF, as polymer, and characterized according to the following characteristics: pH, drug content, spreadability, viscosity, and in vitro drug release. Results and Discussion: Nanocapsules showed mean particle size and zeta potential of 201 ± 6 and −5.73 ± 0.42 nm, respectively. They demonstrated a lower mitotic index (4.62%) compared to free dexamethasone (8.60%). Semisolid formulations presented acidic pH values and adequate drug content (between 5.4% and 6.1% and 100% and 105%, respectively). The presence of nanocapsules in hydrogels led to a decrease in their spreadability factor. Intact nanoparticles were demonstrated by TEM as well as by dynamic light scattering (mean particle size < 300 nm). In vitro studies showed a controlled dexamethasone release from hydrogels containing the drug associated to the nanocapsules following the Higuchi's squared root model (k = 20.21 ± 2.96 mg/cm²/h^1/2) compared to the hydrogels containing the free drug (k = 26.65 ± 2.09 mg/cm²/h^1/2). Conclusion: Taking all these results together, the hydrogel containing D-NC represent a promising approach to treat antiproliferative-related dermatological disorders.

Keywords:

• Dexamethasone
• hydrogels
• in vitro release
• nanocapsules

Acknowledgments

AFO. and MCF. thank Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS) and CAPES/Brasil for their scholarship, respectively. The authors thank FAPERGS, CNPq/Brazil, and Rede Nanocosméticos CNPq/medium-chain triglycerides for the financial support and S.S. Guterres and A.R. Pohlmann from Faculdade de Farmácia and Instituto de Química/UFRGS (Brazil) for the nanoparticle size measurements.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this paper.