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This study investigates the formulation of surfactant-free Pickering emulsions that release a drug at a specific pH to improve its oral bioavailability. The stabilizing particles composed of magnesium carbonate particles. Pickering oil-in-water emulsions stabilized with magnesium carbonate particles and encapsulating a hydrophobic drug model (ibuprofen) were formulated using a high-energy process with rotor-stator turbo mixer (IKA® T25 digital ultra-Turrax). The experimental approach explored the impact of all formulation parameters, dispersed phase and amount of magnesium carbonate particles on the physicochemical properties of Pickering emulsions. The O/W Pickering emulsion was characterized by a methylene blue test, pH and conductivity measurements, and droplet size determination. In addition, Pickering emulsions stabilized by magnesium carbonate particles have the advantage of being destabilized in acidic medium leading to the release of the active principle via the droplets. The acidic medium release study (pH equal to 1.2) showed ibuprofen release as a function of initial droplet loading and saturation concentration. In the simulated intestinal medium at pH equal to 6.8, we found a better release of ibuprofen from emulsions that already had saturation in an acid medium. Thus, the interest of these Pickering emulsions lies on the fact that their non-toxicity and magnesium carbonate particles allow destabilization of the emulsions and release of the drug. These emulsions not only protect patients from the side effects of acid-based drugs, but also contribute to increase the bioavailability of these acidic drugs. Keywords: emulsion -Pickering-magnesium carbonate- ibuprofen-oral bioavailability

Nanomedicine has been a booming industry with the development of nanovectors to encapsulate water-soluble or amphiphilic molecules for drug delivery. As the new therapeutic agents synthesized are increasingly lipophilic, the development of new nanoparticulate vectors allowing their transport and targeting is now a major challenge. These particles are lipid nanoparticles, a few hundred nanometers in diameter, stabilized by a layer of surfactants composed of castor oil and stealth agents. Solid lipid nanoparticles based on shea butter, stabilized by cremophor® ELP, encapsulating griseofulvin, were formulated by the temperature phase inversion method. The shea butter nanoparticles thus obtained were the subject of characterization relating to: determination of the morphology, size, polydispersity index, pH and zeta potential. The results confirm the stability of our preparations. The anti-inflammatory activity of shea butter being known, the tests were carried out on mice. The inflammation was induced by a solution of croton oil acetone. There is a very big improvement in anti-inflammatory activity. This is due to better penetration of the preparation through the different layers of the skin. Griseofulvin release studies have been carried out on our various preparations. Systems designed as reservoirs of active ingredients and intended for a priori controlled release obey kinetics of the order of one-half (½) corresponding to a proportionality between the quantity released and the square root of time. Shea butter in nanoparticulate forms has thus enabled us to considerably prolong the release of griseofulvin. Keywords: Nanoparticles; Shea Butter; Inflammation; Griseofulvin.