Solid Lipid Nanoparticles by Coacervation from Natural Soaps: Preliminary Studies for Oral Delivery of an Insulin Analogue

Background/Objectives: Oral insulin continues to constitute a challenge due to its low uptake by the gut wall and degradation by gastrointestinal proteolytic enzymes. Such concerns might be surmounted by means of nanoparticle delivery. Methods: In this study, glargine insulin has been loaded into solid lipid nanoparticles prepared via coacervation from Shea and Mango soaps, due to hydrophobic ion pairing. Subsequently, ex vivo tied-up-gut experiments were performed with fluorescently labeled peptide. Additionally, re-dispersible oral solid dosage forms (powders and tablets) were obtained from nanoparticle suspensions via freeze-drying and spray-drying. Results: Solid lipid nanoparticles are capable of enhancing peptide permeation into different gut sections. Furthermore, spray-drying permits the preparation, which can be scaled up, of a re-dispersible powder from the nanoparticle suspension. Conclusions: This engineered process is suitable for the formulation of solid oral dosage forms, such as granulates and tablets, and presents promising potential for oral insulin delivery, paving the way for the assessment of its pharmacological efficacy in further in vivo studies.