Electrospray encapsulation of hydrophilic and hydrophobic drugs in poly(L-lactic acid) nanoparticles.

An electrospray method is developed for preparation of beclomethasone-dipropionate- and salbutamol-sulfate-loaded biodegradable poly(L-lactic acid) nanoparticles. Different set-up parameters for electrospraying are examined on particle size, and preparation conditions are optimized for producing spherical-drug-loaded nanoscale particles by controllable processing parameters. Polylactide (PLA)-drug nanoparticles with average diameters of around 200 nm are achieved in a stable cone-jet mode with a flow rate of 4 microL min(-1), polymer concentration of 1%, and ammonium hydroxide content of 0.05%. Morphology and size of the drug-polymer nanoparticles are analyzed by scanning electron microscopy and transmission electron microscopy. Changes in the crystallinity of the PLA polymer and the model drugs are detected by X-ray powder diffraction, and the absence of molecular interactions are confirmed by thermal analyses. The results indicate clearly that electrospraying is a potential method for producing polymeric nanoparticles and for encapsulating both hydrophilic and hydrophobic drugs efficiently into the nanoparticles.

Drug release from nanoparticles embedded in four different nanofibrillar cellulose aerogels.

Highly porous nanocellulose aerogels prepared by freeze-drying from various nanofibrillar cellulose (NFC) hydrogels are introduced as nanoparticle reservoirs for oral drug delivery systems. Here we show that beclomethasone dipropionate (BDP) nanoparticles coated with amphiphilic hydrophobin proteins can be well integrated into the NFC aerogels. NFCs from four different origins are introduced and compared to microcrystalline cellulose (MCC). The nanocellulose aerogel scaffolds made from red pepper (RC) and MCC release the drug immediately, while bacterial cellulose (BC), quince seed (QC) and TEMPO-oxidized birch cellulose-based (TC) aerogels show sustained drug release. Since the release of the drug is controlled by the structure and interactions between the nanoparticles and the cellulose matrix, modulation of the matrix formers enable a control of the drug release rate. These nanocomposite structures can be very useful in many pharmaceutical nanoparticle applications and open up new possibilities as carriers for controlled drug delivery.

Immobilization of protein-coated drug nanoparticles in nanofibrillar cellulose matrices--enhanced stability and release.

Nanosizing is an advanced approach to overcome poor aqueous solubility of active pharmaceutical ingredients. One main problem in pharmaceutical nanotechnology is maintaining of the morphology of the nanometer sized particles during processing and storage to make sure the formulation behaves as originally planned. Here, a genetically engineered hydrophobin fusion protein, where the hydrophobin (HFBI) was coupled with two cellulose binding domains (CBDs), was employed in order to facilitate drug nanoparticle binding to nanofibrillar cellulose (NFC). The nanofibrillar matrix provides protection for the nanoparticles during the formulation process and storage. It was demonstrated that by enclosing the functionalized protein coated itraconazole nanoparticles to the external nanofibrillar cellulose matrix notably increased their storage stability. In a suspension with cellulose nanofibrils, nanoparticles around 100 nm could be stored for more than ten months when the specific cellulose binding domain was fused to the hydrophobin. Also freeze-dried particles in the cellulose nanofibrils matrix were preserved without major changes in their morphology. In addition, as a consequence of formation of the immobilized nanodispersion, dissolution rate of itraconazole was increased significantly, which also enhanced the in vivo performance of the drug.