Improved tretinoin photostability in a topical nanomedicine replacing original liquid suspension with spray-dried powder with no loss of effectiveness.

OBJECTIVE

The use of spray-dried powders containing tretinoin-loaded nanocapsules instead of the original liquid suspension, aimed at the preparation of dermatological nanomedicines with improved photostability, was investigated.

METHODS

Powders were prepared using lactose as a drying adjuvant. Hydrogels were prepared using two approaches: dispersing Carbopol Ultrez 10 in an aqueous redispersion of the powder or incorporating the powder in previously formed hydrogels.

RESULTS AND DISCUSSION

The photodegradation of tretinoin in hydrogels prepared with the powders showed similar half-life times (around 19.5 h) compared to preparations with the original liquid nanocapsules (20.7 ± 1.4 h), regardless of the preparation approach. In addition, the topical nanomedicines prepared with the spray-dried powders presented a significant improvement in tretinoin photostability compared to the formulation containing the non-encapsulated drug.

CONCLUSION

This study verified that the addition of the spray-dried powders containing tretinoin-loaded lipid-core nanocapsules to hydrogels did not influence the photoprotection of the drug compared with the preparation procedure using the original liquid suspension.