Polysaccharides from Adansonia digitata combined with whey protein and alginate enhance the viscosity, swelling, controlled release, and mucoadhesion properties of hydrogels for oral drug delivery

• Baobab polysaccharides enhance whey proteins–alginate hydrogel structure and stability. • Whey proteins–alginate–baobab hydrogels show strong mucoadhesion in vitro and ex vivo. • Baobab addition reduces swelling and slows release of encapsulated active substance. • Baobab–based formulations offer a natural excipient for oral bioadhesive delivery. The potential of Adansonia digitata (baobab) pulp polysaccharides (BB), combined with whey protein (WP) and alginate (ALG), was evaluated as a novel pharmaceutical excipient to enhance the viscosity, swelling behavior, controlled release, and mucoadhesive properties of hydrogels prepared by the ionotropic gelation technique. Hydrogels based on BB, WP, and ALG, alone or in combinations (WP/BB, WP/ALG, ALG/BB, and WP/ALG/BB), were characterized by infrared spectroscopy and zeta potential measurements. Rheological, swelling, controlled release, and mucoadhesion studies were conducted to assess the functional contribution of BB and its synergistic effects with WP and ALG. All polymers exhibited viscoelastic solid behavior (G′ > G″). For each polymer, with or without crosslinking, molecular interactions were observed, leading to variations in the Tan δ parameter. The crosslinked WP/ALG/BB hydrogel exhibited reduced polymer swelling and provided a more sustained release of the incorporated active substance. In vitro and ex vivo studies demonstrated strong interactions between the polymeric matrices and intestinal mucus, with the WP/ALG/BB system showing the highest mucoadhesion. Further in vivo investigations are needed to confirm the ability of BB to enhance the oral bioavailability of active substances. Overall, Adansonia digitata pulp polysaccharides, in combination with whey protein and alginate, represent a promising natural excipient for the development of bioadhesive hydrogels and cold-gelled delivery systems in pharmaceutical formulations.