Tablets containing drug-loaded polymeric nanocapsules: an innovative platform.

The aim of the present work was to evaluate the feasibility to convert drug-loaded nanocapsule suspensions in a solid dosage form (tablets). Dexamethasone was used as a model drug due to its low aqueous solubility and fast drug release from conventional tablets. Granules containing dexamethasone-loaded nanocapsules were obtained by a wet granulation process using a dispersion of polyvinylpirrolidone/nanocapsules as a binder system. Granules were compressed in an eccentric compression machine (D-NC-T). A control formulation (tablets without nanocapsules) was also prepared (D-T). Tablets were characterized by means of mean weight, hardness, friability, diameter, thickness, disintegration time, drug content, morphological analysis by scanning electron microscopy (SEM), and in vitro drug release studies. D-NC-T showed adequate physicochemical characteristics according to the pharmacopeial requirements in terms of mean weight, hardness, friability, disintegration time and drug content. Intact nanocapsules in tablets were observed by SEM. In vitro drug release studies showed a slower release of dexamethasone from these tablets (D-NC-T) compared to the control formulation (D-T). Results showed that these tablets represent an interesting platform to the development of oral drug delivery systems containing polymeric nanocapsules.

Development and validation of a fast RP-HPLC method for the determination of clobetasol propionate in topical nanocapsule suspensions.

A simple and rapid high-performance liquid chromatographic method is validated for the determination of clobetasol propionate in topical nanocapsule suspensions. The method is carried out on an RP-18 column with a mobile phase composed of methanol-water (80:20 v/v) and UV detection at 241 nm. The method validation yields good results with respect to linearity, specificity, precision, accuracy, and robustness. The calibration curve in the range of 5.0-40.0 microg/mL shows a correlation coefficient of 0.9999. Precision (intra-day and inter-day) is demonstrated by a relative standard deviation lower than 1.5%. Accuracy is assessed by the recovery test of clobetasol propionate from sample matrixes (98.33 +/- 0.88%). In conclusion, the method is suitable to be applied to assay clobetasol propionate in topical formulations of polymeric nanocapsules, avoiding the use of a buffer solution in the mobile phase.

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

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/cm(2)/h(1/2)) compared to the hydrogels containing the free drug (k = 26.65 +/- 2.09 mg/cm(2)/h(1/2)). CONCLUSION: Taking all these results together, the hydrogel containing D-NC represent a promising approach to treat antiproliferative-related dermatological disorders.

Drying polymeric drug-loaded nanocapsules: the wet granulation process as a promising approach.

The industrial development of polymeric nanoparticle suspensions is still limited due to their low physicochemical stability. In this paper, we evaluated the wet granulation process as an alternative method to dry polymeric nanocapsules using dexamethasone as drug model. Nanocapsule suspensions were used as granulating liquid as well as a drug-loaded-nanocarrier in the wet granulation process. Granules were evaluated regarding their drug content, mean particle size, yield, moisture content, flow properties, stability on storage, recovery studies after water redispersion and morphological characteristics (SEM). Granules containing dexamethasone-loaded polymeric nanocapsules presented good drug content (approximately 94%) and were stable for 6 months at room temperature. Morphological analyses showed nanostructures on their surface and the nanoparticles were recovered after redispersing the granules in water. These results suggest that wet granulation can be an interesting alternative to dry drug-loaded nanocapsule suspensions.