Synergistic effect of PLGA nanoparticles and submicron triglyceride droplets in enhancing the intestinal solubilisation of a lipophilic weak base

A novel hybrid microparticulate system composed of poly(lactic-co-glycolic) acid (PLGA) nanoparticles and submicron medium-chaintriglyceride (MCT) droplets was fabricated to overcome the pH-dependent solubility and precipitation challenges associated with a model poorly water-soluble weak base, cinnarizine (CIN). MolecularCIN was confined within both the lipid and polymer phase of PLGA-lipid hybrid (PLH) and PLGA-lipid-mannitol hybrid (PLMH) particles, which offered significant biopharmaceutical advantages incomparison to the unformulated drug, submicron MCT droplets and PLGA nanoparticles. This was highlighted by a substantial reduction in the pH-induced precipitation during invitro gastrointestinal two-step dissolution studies. A >2.5-fold solubilisation enhancement was observed for the composite particles during simulated intestinal conditions, compared to pureCIN. Furthermore, the drug solubilisation capacity during in vitro intestinal digesting conditions was ~2–2.5 times greater for PLMH particles compared to the precursor emulsiondroplets and PLGA nanoparticles. The observations from this study indicate that a synergy exists between the degradation products of PLGA nanoparticles and lipid droplets, whereby the dual-phaserelease and dissolution mechanism of the hybrid particles aids in prolonging pH-provoked precipitation. Subsequently, the ability for PLGA polymers and oligomers to act as polymeric precipitationinhibitors has been highlighted for the first time.

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