Abstract
Engineering of multifunctional drug nanocarriers combining stability and good release properties remains a great challenge. In this work, natural polymers κ-carrageenan (κ-CAR) and chitosan (CS) were deposited onto olive oil nanoemulsion droplets (NE) via layer-by-layer (LbL) self-assembly to study the release mechanisms of the anti-inflammatory diflunisal (DF) as a lipophilic drug model. The nano-systems were characterized by dynamic light scattering (DLS), zeta potential (ζ-potential) measurements, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (XEDS) and Fourier transform infrared spectroscopy (FTIR) to confirm the NE-coating with polymer layers. In addition, kinetic release studies of DF were developed by the dialysis diffusion bag technique. Mathematical models were applied to investigate the release mechanisms. The results showed that stable and suitably sized nanocapsules (~300 nm) were formed. Also, the consecutive adsorption of polyelectrolytes by charge reversal was evidenced. More interestingly, the drug release mechanism varied depending on the number of layers deposited. The nanosized systems containing up to two layers showed anomalous transport and first order kinetics. Formulations with three and four layers exhibited Case II transport releasing diflunisal with zero order kinetics. Hence, our results suggest that these polyelectrolyte nanocapsules have great potential as a multifunctional nanocarrier for drug delivery applications.
Highlights
In recent years, interest in the field of active compounds release has increased
The aim of this paper is to report the formulation, characterization, and drug release properties of biocompatible multilayer nanocapsules based on a nanoemulsion template which is stabilized by dodecyltrimethylammonium chloride (DTAC)
It is worth mentioning that, at pH 1.2, DF was not released from any of the systems, or at least it was not detectable by spectrofluorimetry analysis. These results suggest that the DF delivery from the oil core κ-CAR/CS nanocapsules is pH sensitive, and this lipophilic drug might be released in gastrointestinal medium and the blood system rather than in the acidic stomach [51]
Summary
The result has been the development of innovative drug nanocarriers to enhance drug bioavailability, protect the molecules from the biological environment, and provide sustained release. This has great potential for multi-compartmental delivery devices [1]. In the field of drug delivery, several polymers are recognized as promising materials for the preparation of nanocarriers. They functionalize surfaces, acting as a polyelectrolyte coating for different templates such as spheres or films [5,6,7]. Taking advantage of the self-assembly properties of the polyelectrolytes, they can form multilayer polymeric structures via a layer-by-layer technique (LbL), which consists of the alternate deposition of oppositely charged materials, mainly polyelectrolytes, on to templates of different size and composition through electrostatic interactions [1,4]
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