Microencapsulation of retinoic acid by atomization into biopolymeric matrices: Binary and ternary blends of alginic acid sodium, xanthan gum and modified chitosan

Retinoic acid (RA) is recognized for its therapeutic value in the treatment of several malignancies. Particularly, it is a successful antitumor agent used in patients with acute promyelocytic leukaemia (APL). Development of an appropriate delivery system for RA administration might improve the stabilization of this retinoid under undesirable conditions, reduce severe side-effects related to RA administration and increase the amount of RA that reach the target cells/tissues. In the present work, binary and ternary blends of biopolymers (xanthan gum + alginic acid sodium, modified chitosan + alginic acid sodium, modified chitosan + xanthan gum and modified chitosan + xanthan gum + alginic acid sodium) were considered to prepare oil-in-water emulsions for RA-loaded biopolymer-based delivery systems formation using spray-drying technology. Rheological properties (i.e. viscosity), stability and droplet size distribution of the emulsions were analysed. Product yield varied from 16 to 41% among all the microparticles produced (empty and loaded with coconut oil – with and without RA – and surfactant). Microparticles exhibited a spherical form, smooth or rough surfaces and a mean diameter between 2.88 ± 0.01 and 6.9 ± 0.4 μm, considering a volume size distribution. Considering RA-loaded microparticles, encapsulation efficiency was significantly higher for the microparticles composed by the xanthan gum + alginic acid sodium blend (76 ± 4%). Moreover, the slower RA release (almost 7 h) was observed from most of the microparticles composed by alginic acid sodium. For microparticles composed by the modified chitosan + alginic acid sodium blend the shortest RA release time (100 min) was observed.