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Development of Nanoemulsions and Solid Lipid Nanoparticles Loaded with Retinoic Acid and a Lipophilic Amine for Treatment of Solid Tumors Guilherme Carneiro (Pg), Elton Luis Silva (Pg), Ana Paula De Sousa Pereira (Ic), Mônica Cristina De Oliveira e Lucas Antônio Miranda Ferreira. Department of Pharmaceutics, Faculty of Pharmacy/UFMG
Introduction and Objectives: All-trans retinoic acid (RA), a lipophilic vitamin A derivative, has been investigated in the treatment of cancer. Due to the highly variable bioavailability of oral RA, development of alternative parenteral dosage forms is required. Nanoemulsions (NE) and solid lipid nanoparticles (SLN) can favorably alter the chemical stability and biological activities of RA. However, encapsulation efficiency (EE) in both systems is usually low. The aim of this study was to develop novel lipid carriers,
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namely NE and SLN, loaded with RA and stearylamine (SA), a lipophilic amine, which was used for formation of ion pairing with RA, a lipid acid, and to improve the EE. Material and Methods: Both systems were prepared by hot homogenization method using an emulsification-ultrasound. Lipid carriers were characterized for EE, size and zeta potential. Results and Conclusions: The EE in NE with 0, 0.1 and 0.2% of SA was
Janeiro/Fevereiro/Março 2011
62 ± 4.5; 98 ± 3.5 and 99 ± 3.5% respectively. In SLN with 0 and 0.2% of SA, the EE was 66 ± 1 and 101 ± 7%, respectively. Therefore, the EE in NE and SLN significantly improved in presence of the lipophilic amine. Size ranged from 70 to 121 nm for NE and from 144 to 167 nm for SLN. In conclusion, the formation of ion pairing between RA and SA increased the EE. These systems present potential for controlled release of RA after parenteral administration. Financing: Fapemig; CNPq