PH-sensitive Pickering Emulsion Stabilized by Hydroxyapatite Nanoparticles: Stability and Controlled Release Study

Papa Mady Sy,Alphonse Rodrigue Djiboune,Cecile Diop,Toro Diop,Mamadou Mbodj,Gora Mbaye,Mounibe Diarra,Sidy Mouhamed Dieng,Mamadou Soumboundou,Louis Augustin Diaga Diouf

doi:10.11648/j.ejb.20200802.16

Abstract

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 nanoparticles composed of hydroxyapatite were obtained by a process of nanoprecipitation. Pickering oil-in-water emulsions stabilized with hydroxyapatite nanoparticles 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 hydroxyapatite nanoparticles on the physicochemical properties of Pickering emulsions. The system was characterized by a methylene blue test, pH and conductivity measurements, and droplet size determination. In addition, Pickering emulsions stabilized by hydroxyapatite nanoparticles 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 hydroxyapatite nanoparticles have advantage of being biocompatible because having the same mineral composition as bones and teeth. In addition, they 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.

Highlights

In many industrial sectors such as pharmacy [1], cosmetics [2], agri-food [3] and chemistry [4], emulsions are formulations used to obtain useful properties or suitable compositions
Papa Mady Sy et al.: pH-sensitive Pickering Emulsion Stabilized by Hydroxyapatite
The formulation of pH-dependent Pickering emulsions for controlled release of active substances to improve their oral bioavailability is precisely the general objective of this work. The interest of these Pickering emulsions lies on the fact that their non-toxicity and hydroxyapatite nanoparticles have advantage of being biocompatible because having the same mineral composition as bones and teeth

Summary

Introduction

In many industrial sectors such as pharmacy [1], cosmetics [2], agri-food [3] and chemistry [4], emulsions are formulations used to obtain useful properties or suitable compositions. These emulsions are metastable dispersed systems consisting of least two immiscible liquids and an amphiphilic agent. The system created does not correspond to a thermodynamically stable state, the most stable state would consist in the macroscopic separation of the two fluids These metastable dispersed systems are conventionally stabilized by surfactant molecules. On the one hand for the sake of environmental respect and on the other hand for the safety of consumers, surfactants can be toxic and harmful to the environment and harmful to consumers [10, 11]

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