Micro and nano polycaprolactone particles preparation by pulsed back-and-forward cross-flow batch membrane emulsification for parenteral administration

Production of α-Tocopherol–Chitosan Nanoparticles by Membrane Emulsification

α-tocopherol (α-T) has the highest biological activity with respect to the other components of vitamin E; however, conventional formulations of tocopherol often fail to provide satisfactory bioavailability due to its hydrophobic characteristics. In this work, α-tocopherol-loaded nanoparticles based on chitosan were produced by membrane emulsification (ME). A new derivative was obtained by the cross-linking reaction between α-T and chitosan (CH) to preserve its biological activity. ME was selected as a method for nanoparticle production because it is recognized as an innovative and sustainable technology for its uniform-particle production with tuned sizes and high encapsulation efficiency (EE%), and its ability to preserve the functional properties of bioactive ingredients operating in mild conditions. The reaction intermediates and the final product were characterized by 1HNMR, Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC), while the morphological and dimensional properties of the nanoparticles were analyzed using electronic scanning microscopy (SEM) and dynamic light scattering (DLS). The results demonstrated that ME has high potential for the development of α-tocopherol-loaded nanoparticles with a high degree of uniformity (PDI lower than 0.2), an EE of almost 100% and good mechanical strength, resulting in good candidates for the production of functional nanostructured materials for drug delivery. In addition, the chemical bonding between chitosan and α-tocopherol allowed the preservation of the antioxidant properties of the bioactive molecule, as demonstrated by an enhanced antioxidant property and evaluated through in vitro tests, with respect to the starting materials.

Mucoadhesive nanocrystal-in-microspheres with high drug loading capacity for bioavailability enhancement of silybin

Nanocrystals, due to high drug loading efficiency, have drawn large attention as nanotechnology to enhance solubility and bioavailability of poorly soluble drugs. However, most nanocrystals still encountered low oral absorption percentage due to its insufficient retention time in the gastrointestinal tract (GI). In this work, silybin (SB) as model drug was fabricated to nanocrystals, and further loaded into a mucoadhesive microsphere to increase the GI retention. Such mucoadhesive microspheres were prepared with a wet media milling technique followed by coagulation and film coating. Nanocrystals and microspheres were thoroughly characterized by diverse complementary techniques. As results, such delivery system displayed an encapsulation efficiency of approximately 100 % and a drug loading capacity of up to 35.41 ± 0.31 %. In addition, mucoadhesiveness test ex vivo conducted with rat intestine showed that film-coated microspheres were retained for more than 1 h. Benefiting from nanocrystals technology, the drug cumulative release percentage of the microspheres was remarkable improved compared to unprocessed one in vitro. Finally, pharmacokinetics studies in rats showed a significant 3-fold increase of drug oral bioavailability compared to unprocessed SB. The current study demonstrates that the developed delivery vehicle can enhance the bioavailability of SB by increasing its dissolution percentage as well as through extending retention time in the GI tract, and achieve high drug loading capacity.