pH-responsive hydrogel containing curcumin-loaded lipid nanocapsules for oral curcumin’s stability, bioaccessibility and intestinal absorption improvement

A liquid formulation with suitable consistency and sustained release characteristics can improve compliance in users with dysphagia. In the study, we prepared curcumin-loaded lipid nanocapsules (Cur-LNCs) and incorporated it in a mixture of sodium alginate, dextrin, calcium chloride and sodium citrate to form a pH-responsive pre-hydrogel solution (SA-DEX:Cur-LNCs). The SA-DEX:Cur-LNCs exhibited a pH-responsive solution-gel conversion: solubilized at near neutral (pH = 7) and rapidly gelatinized to a strong elastic gel at stomach acid (pH = 2.5). The SA-DEX:Cur-LNCs could effectively improve the thermal and pH stability of Cur, and maintain its antioxidant effect. Interestingly, the bioaccessibility of SA-DEX:Cur-LNCs in gastrointestinal was significantly increased to 37.00% when compared with free Cur. The SA-DEX:Cur-LNCs also significantly improved the small intestinal absorption of Cur, being 16 times higher than that of free Cur. Therefore, incorporating lipid nanocapsule in pH-responsive pre-hydrogel provided a new oral administration platform of hydrophobic bioactive compounds for compliance improvement of users with dysphagia.