title: Spray-dried powders containing tretinoin-loaded engineered lipid-core nanocapsules: development and photostability study.
abstract: The influence of the spray-drying process on the ability of engineered lipid-core nanocapsules to protect tretinoin against UV degradation was evaluated. This approach represents a technological alternative to improve the microbiological stability, storage and transport properties of such formulations. Tretinoin-loaded lipid-core nanocapsules or tretinoin-loaded nanoemulsion were dispersed in lactose (10% w/v) and fed in the spray-drier to obtain a solid product (spray-dried powder containing tretinoin-loaded nanocapsules or nanoemulsion--SD-TTN-NCL or SD-TTN-NE, respectively). SD-TTN-NE showed a lower (p < or = 0.05) percentage of encapsulation (89 +/- 1%) compared to SD-TTN-NCL (94 +/- 2%). Redispersed SD-TTN-NCL and SD-TTN-NE showed z-average sizes of 204 +/- 2 nm and 251 +/- 9 nm, which were close to those of the original suspensions (220 +/- 3 nm and 239 +/- 14 nm, respectively). Similar percentage of photodegradation were determined for tretinoin loaded in nanocapsules (26.15 +/- 4.34%) or in the respective redispersed spray-dried powder (28.73 +/- 6.19 min) after 60 min of UVA radiation exposure (p > 0.05). Our experimental design showed for the first time that spray-dried lipid-core nanocapsules are able to protect tretinoin against UVA radiation, suggesting that the drying process did not alter the supramolecular structure of the lipid-core nanocapsules. Such powders are potential intermediate products for the development of nanomedicines containing tretinoin.
authors: Programa de Pós-Graduação em Ciências Farmacêuticas, Av. Roraima, 1000, Universidade Federal de Santa Maria, Santa Maria, RS 97105-900, Brazil.
authors: M C L
authors: MC
authors: Marchiori
authors: A F
authors: AF
authors: Ourique
authors: C de B
authors: Cde B
authors: da Silva
authors: R P
authors: RP
authors: Raffin
authors: A R
authors: AR
authors: Pohlmann
authors: S S
authors: SS
authors: Guterres
authors: R C R
authors: RC
authors: Beck