Hydrogel containing dexamethasone-loaded nanocapsules for cutaneous administration: Preparation, characterization, and in vitro drug release study
ABSTRACT Our group previously reported the development of dexamethasone-loaded polymeric nanocapsules as an alternative for topical dermatological treatments.
Our study aimed to prepare and characterize a hydrogel containing this system to improve the effectiveness of the glucocorticoid for cutaneous disorders.
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
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/cm(2)/h(1/2)) compared to the hydrogels containing the free drug (k = 26.65 +/- 2.09 mg/cm(2)/h(1/2)).
Taking all these results together, the hydrogel containing D-NC represent a promising approach to treat antiproliferative-related dermatological disorders.
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ABSTRACT: Experience has brought to light certain differences between what the research community produces and what technology users need. These differences may be caused by a divergence in the standards held by users and practitioners. The divergence exists in four major areas: education, means of implementation, communication with appropriate parties, and need satisfaction. The focus of practitioners is on technology itself, while the focus of users is on the goals to which technology is applied. These goals cannot be grasped by people who have had a device-oriented instead of a comprehension-oriented education. Standards in the means of implementation is another source of divergence. Frequently, what is seen as a good language/hardware suite from the practitioner's point of view is not so good from a user's point of view. Communication with appropriate parties is a related diverging standard. If the customer cannot use a product and understand it then it has no value. Whatever standards are selected, they must be focused on customer needsAerospace and Electronics Conference, 1992. NAECON 1992., Proceedings of the IEEE 1992 National; 06/1992
Conference Paper: Direct optical control: a lightweight backup consideration[Show abstract] [Hide abstract]
ABSTRACT: The author addresses the benefits and issues associated with direct optical flight control and discusses the status of work to bring it to reality. It is noted that the approach considered is compatible with existing and future fly-by-wire and fly-by-light actuation approaches, can be used as a dedicated backup or integrated with primary fly-by-light systems over common command paths, and can be implemented as a minimal or extensive backup with very little weight penalty. In addition, it can be effectively retrofitted to existing fly-by-wire systems, provides enhanced survivability and mission capability in severe EMI (electromagnetic interference) environments, and provides a simple, reliable, and inexpensive backup capability. Direct optical control can be implemented as analog, pulsewidth modulated, etc. and is well adapted for harsh aircraft environments. It does not require new technologies to be developed for effective implementation, is extremely well adapted for power-by-wire actuation systems, and if implemented properly it can substantially reduce aircraft wiring and associated shielding maintenanceAerospace and Electronics Conference, 1992. NAECON 1992., Proceedings of the IEEE 1992 National; 06/1992
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ABSTRACT: The aim of the present work was to develop and characterize a chitosan hydrogel containing capsaicinoids-loaded nanocapsules intended for topical delivery. Such system is promising since it brings together the skin bioadhesion and film forming capability of chitosan and the control of the drug release due to the reservoir property of the nanocapsules. The hydrogels showed pH values between 4.2 and 4.4, suitable for topical administration, as a consequence of lactic acid in the formulations. The consistence values (Pa.sn) /flow indexes (n = dimensionless) were 19.64 ± 2.61/ 0.76 ± 0.03 and 13.12 ± 0.93/0.82 ± 0.01 for the gels containing the nanocapsule suspension or exclusively water, respectively, demonstrating the effect of the nanocapsules on the slight increase of the gel consistence. The nanocapsules may also interfere in the interaction between chitosan chains and in the polymer network. The pseudoplastic behavior of the hydrogels did not change after the incorporation of nanocapsules. The release study showed a more controlled release of capsaicin and dihydrocapsaicin from the hydrogel containing nanocapsules comparing with the hydrogels containing free capsaicinoids. This chitosan hydrogel containing drug-loaded nanocapsules is likely interesting when a controlled release is intended.Soft Materials 10/2010; 8(4-4):370-385. DOI:10.1080/1539445X.2010.525161 · 1.24 Impact Factor