Granules in the improvement of oral heparin bioavailability

International audienc

Evaluation of subcutaneous forms in the improvement of pharmacokinetic profile of warfarin

International audienceWe attempted to prepare a subcutaneous pharmaceutical form of warfarin based on a suspension or poly(ε-caprolactone) microparticles to improve patient adherence. The warfarin suspension had a mean particle size of 20.0 μm and in vitro release close to 100% in 72 h. Microparticle size and encapsulation efficiencies ranged from 54.0 to 80.0 μm and 37.0 to 47.0%, respectively. After 72 h, warfarin microparticles exhibited in vitro drug release ranging from 62.0 to 80.0%. Warfarin subcutaneous dosage forms were administered to rabbits. Plasma concentration of warfarin was determined and biological activity was measured by prothrombin time monitoring. The observed relative bioavailabilities calculated from plasma concentrations and prothrombin times were 54.2 and 92.1%, and 61.8 and 61.4% for suspension and microparticles, respectively

Injectable PLA-based in situ forming implants for controlled release of Ivermectin a BCS Class II drug: solvent selection based on physico-chemical characterization.

International audienceIn situ forming implants (ISI) prepared from biodegradable polymers such as poly(D,L-lactide) (PLA) and biocompatible solvents can be used to obtain sustained drug release after parenteral administration. The aim of this work was to study the effect of several biocompatible solvents with different physico-chemical properties on the release of ivermectin (IVM), an antiparasitic BCS II drug, from in situ forming PLA-based implants. The solvents evaluated were N-methyl-2-pyrrolidone (NMP), 2-pyrrolidone (2P), triacetine (TA) and benzyl benzoate (BB). Hansen's solubility parameters of solvents were used to explain polymer/solvent interactions leading to different rheological behaviours. The stability of the polymer and drug in the solvents were also evaluated by size exclusion and high performance liquid chromatography, respectively. The two major factors determining the rate of IVM release from ISI were miscibility of the solvent with water and the viscosity of the polymer solutions. In general, the release rate increased with increasing water miscibility of the solvent and decreasing viscosity in the following order NMP>2P>TA>BB. Scanning electron microscopy revealed a relationship between the rate of IVM release and the surface porosity of the implants, release being higher as implant porosity increased. Finally, drug and polymer stability in the solvents followed the same trends, increasing when polymer-solvent affinities and water content in solvents decreased. IVM degradation was accelerated by the acid environment generated by the degradation of the polymer but the drug did not affect PLA stability

In vivo magnetomotive optical molecular imaging using targeted magnetic nanoprobes

Dynamic magnetomotion of magnetic nanoparticles (MNPs) detected with magnetomotive optical coherence tomography (MM-OCT) represents a new methodology for contrast enhancement and therapeutic interventions in molecular imaging. In this study, we demonstrate in vivo imaging of dynamic functionalized iron oxide MNPs using MM-OCT in a preclinical mammary tumor model. Using targeted MNPs, in vivo MM-OCT images exhibit strong magnetomotive signals in mammary tumor, and no significant signals were measured from tumors of rats injected with nontargeted MNPs or saline. The results of in vivo MM-OCT are validated by MRI, ex vivo MM-OCT, Prussian blue staining of histological sections, and immunohistochemical analysis of excised tumors and internal organs. The MNPs are antibody functionalized to target the human epidermal growth factor receptor 2 (HER2 neu) protein. Fc-directed conjugation of the antibody to the MNPs aids in reducing uptake by macrophages in the reticulo-endothelial system, thereby increasing the circulation time in the blood. These engineered magnetic nanoprobes have multifunctional capabilities enabling them to be used as dynamic contrast agents in MM-OCT and MRI