Budesonide-hydroxypropyl-β-cyclodextrin inclusion complex in binary poloxamer 407/403 system for ulcerative colitis treatment: A physico-chemical study from micelles to hydrogels

• The complexation with HP-β-CD and the incorporation in PL systems improved the BUD solubility in simulated colon fluids.
• BUD:HP-β-CD inclusion complex reduced the PL sol–gel transition phase temperature and favored the micelle–micelle network.
• PL407 or PL407-PL403 systems were not capable to displace BUD from the HP-β-CD cavity.
• The BUD:HP-β-CD complex in PL 407-PL403 presented progressive drug release until reach the interface hydrogel-medium.

Budesonide (BUD) is a glucocorticoid widely used for the treatment of ulcerative colitis. In this work, we propose the study of the system BUD-HP-β-CD inclusion complex incorporated into PL 407 and PL407-PL403 thermoreversible hydrogels, considering physico-chemical and pharmaceutical aspects. Complexation between BUD and HP-β-CD was confirmed by phase solubility studies (1:1 stoichiometry, Kc = 8662.8 M−1), DSC, FTIR and microscopy analyzes. BUD solubility in simulated upper and lower colon fluids was improved in a dependence of HP-β-CD and PL 407 or PL407-PL403 association. Micellar hydrodynamic diameter studies showed the interaction between HP-β-CD and PL blocks, as well as the reorganization of the micellar system in the presence of BUD and its inclusion complex. Micellization temperature (Tm) was not shifted, but sol–gel phase transition studies showed that in the presence of BUD, HP-β-CD or BUD:HP-β-CD complex, the association PL407-PL403 favored the gel formation close to the physiological temperature. Physico-chemical and in vitro release assays studies revealed no competitive displacement of BUD from the HP-β-CD cavity evoked by PL407 or PL407-PL403 addition. These findings point out the BUD-HP-β-CD in PL-based hydrogels as strategies for future investigations on development of new pharmaceutical formulations for the treatment of ulcerative colitis.

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