Tailoring oleogel-in-hydrogel pickering emulsion fluid gels as an oral delivery system for different levels of dysphagia: From microstructure to rheological properties

Dysphagia-affected populations are facing crucial challenges on oral administration of medicines and health products because of swallowing malfunction with a high risk of aspiration. The current countermeasures that relied mainly on modification of existing formulations with thickened liquids comes with potential hazards, e.g., bioavailability alterations and unsatisfactory safety. Thus, dysphagia-specific oral delivery system is in critical need of development. Herein, a swallowing dynamics-inspired, oleogel-in-hydrogel Pickering emulsion fluid gel was proposed as a versatile oral delivery system for patients with dysphagia. With the dual structure of high acyl gellan gum (HAG) fluid gel and whey protein isolate (WPI) stabilized oleogel-in-hydrogel Pickering emulsion gel, the novel system demonstrated the potential to tackle both swallowing and drug encapsulation challenges. Specifically, it displayed good shear flowability during shearing and appropriate extensional capabilities after shearing which are well-matched with swallowing dynamics to facilitate ease and safe swallowing. Moreover, the oleogel-in-hydrogel Pickering emulsion gel structure enables its versatile loading potential for both hydrophilic and lipophilic substances. Remarkably, the microstructure and the related rheological properties of this novel system could be tailored by controlling critical determinants in the formation of fluid gels, namely HAG content and process mixing rate. By adjusting these two parameters, the fluid gels could be customized as preparations with different thickness level for mild, moderate and severe dysphagia, respectively. In conclusion, this proposed approach offers a promising rheologically-tunable oral delivery system for administering bioactives to patients with different levels of dysphagia.