Polymeric drug delivery micelle-like nanocarriers for pulmonary administration of beclomethasone dipropionate.

In this paper, the potential of novel polymeric micelles as drug delivery systems for Beclomethasone Dipropionate (BDP) administration into the lung is investigated. These nanostructures are obtained starting from α,ß-poly(N-2-hydroxyethyl)-d,l-aspartamide (PHEA), which was subsequently functionalized with O-(2-aminoethyl)-O'-methylpolyethylenglycole (PEG2000), ethylenediamine (EDA) and lipoic acid (LA), obtaining PHEA-PEG2000-EDA-LA graft copolymer. Empty and drug-loaded micelles possess adequate chemical-physical characteristics for pulmonary administration such as spherical shape, slightly positive surface charge and mean size of about 200nm. Besides, BDP-loaded micelles, obtained with a Drug Loading equal to 5wt%, result to be stable in physiological-mimicking media, protecting the drug from hydrolysis and giving a sustained drug release profile. Moreover, the micelle-like structure and surface characteristics seems to improve drug permeation through the mucus layer. Finally, it is also demonstrated that BDP-loaded PHEA-PEG2000-EDA-LA micelles are able to increase cell uptake of BDP of about 44wt% compared to Clenil® on 16-HBE cells and possess an higher biocompatibility in comparison with the same commercial formulation.

Realization of polyaspartamide-based nanoparticles and in vivo lung biodistribution evaluation of a loaded glucocorticoid after aerosolization in mice.

In this study, novel polymeric nanoparticles (NPs) were developed and their potential as carriers for beclomethasone dipropionate (BDP) into the lung after aerosolization was demonstrated by in vivo studies in mice. In particular, these NPs were obtained starting from two polyaspartamide-based copolymers which were synthesized by chemical reaction of α,ß-poly(N-2-hydroxyethyl)-dl-aspartamide (PHEA) and its pegylated derivative (PHEA-PEG2000) with poly(lactic acid) (PLA). To obtain nanosized particles, the high pressure homogenization (HPH)-solvent evaporation method was followed by using an organic phase containing both PHEA-PLA and PHEA-PEG2000-PLA (at a weight ratio equal to 1:1), lactose as cryoprotectant and no surfactant was adopted. PHEA-PLA/PHEA-PEG2000-PLA NPs were characterized by a quite spherical shape, ζ potential slightly negative, and size lower than 50 and 200nm, respectively, for empty and BDP-loaded NPs. In vivo biodistribution of BDP and its metabolites in various lung compartments, i.e. bronchoalveolar lavage fluid (BALF), alveolar macrophages (MPG) obtained from BALF, and lung tissue, was carried out at 3h post-administration in mice by aerosolization of BDP-loaded NPs or free BDP (commercial formulation, Clenil(®)) at the dose of 0.5mg/kg BDP. Results demonstrated that BDP entrapped into NPs reached all analyzed lung compartments and were internalized by both alveolar MPG and respiratory epithelial cells, and detected amounts were comparable to those of Clenil-treated mice. Moreover, the entrapment into NPs protects the drug from the enzymatic hydrolysis, allowing a significant lower amount of beclomethasone (BOH) into the lung tissue and BALF than that obtained after Clenil administration.

Lipid nanocarriers containing ester prodrugs of flurbiprofen preparation, physical-chemical characterization and biological studies.

In this paper, the preparation, chemical-physical, technological and in vitro characterization of nanostructured lipid carriers (NLC) carrying R-flurbiprofen ester prodrugs, were analyzed for a potential pharmaceutical application. R-flurbiprofen was chosen as a model drug because it has been found to play an effective role in counteracting secretases involved in neurodegenerative diseases, although it does not cross the Blood Brain Barrier (BBB). In this study, two R-flurbiprofen ester prodrugs (ethyl and hexyl) were successfully synthesized and entrapped into non-pegylated and pegylated NLC. The obtained systems showed average diameters in the colloidal size range, negative zeta potential values and a good loading capacity. Drug release studies in physiological media on all drug-loaded samples showed a controlled drug release both at at pH 7.4 (containing esterase or not) and in human plasma of each ester prodrug, with a complete hydrolysis to R-flurbiprofen in media containing esterase. Empty and ethyl prodrug-loaded NLC were also demonstrated to have no cytotoxicity on human neuroblastoma (LAN5) cells, while hexyl prodrug-loaded NLC caused a reduction of cell viability probably due to a better capability of prodrug-loaded NLC to cross the cell membrane than the free compounds. These data were confirmed by microscopical observation, in which only the cells treated with hexyl prodrug-loaded NLC showed morphological changes. Outcoming data suggest that NLC could be potential carriers for parenteral administration of ethyl ester of R-flurbiprofen in the treatment of neurodegenerative diseases such as Alzheimer's.

Crosslinked hyaluronan with a protein-like polymer: novel bioresorbable films for biomedical applications.

In this work, novel hydrogel films based on hyaluronan (HA) chemically crosslinked with the alpha,beta-poly(N-2-hydroxyethyl) (2-aminoethylcarbamate)-D,L-aspartamide (PHEA-EDA) were produced by solution casting method. The goal was to exploit both the biological key role of HA in tissue repair and regeneration, and the versatility of a synthetic protein-like polymer as the PHEA-EDA, in order to obtain biomaterials with physicochemical and biological properties suitable for a clinical use. By varying the molar ratio between the PHEA-EDA amino groups and HA carboxyl groups, three different films were obtained and characterized. Particularly FTIR, swelling, hydrolysis, and enzymatic degradation studies were performed. In addition, the cytocompatibility of HA/PHEA-EDA hydrogel films was evaluated using human derm fibroblasts, by means of MTT and trypan blue exclusion assays. The high swelling capability, the long-term hydrolysis resistance, and the resistance to hyaluronidase greater than that of only HA, together with the cell compatibility, have suggested the potential application of these novel HA-based hydrogel films in the biomedical field of tissue engineering.

Biocompatible polymeric micelles with polysorbate 80 for use in brain targeting.

In this paper, the synthesis and characterization of novel amphiphilic graft copolymers based on an α,ß-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA) backbone and D,L-polylactic acid (PLA) hydrophobic side chains are reported. These copolymers were obtained starting from PHEA-ethylenediamine (PHEA-EDA), which was functionalized with polysorbate 80 (PS(80)) and/or PLA in order to obtain the PHEA-EDA-PS(80)-PLA and PHEA-EDA-PLA samples, respectively. The degrees of derivatization, DD(PS80) and DD(PLA), of PHEA-EDA-PS(80)-PLA, calculated by (1)H-NMR, resulted in being 1.2 ± 0.03 mol% and 0.54 ± 0.05 mol%, respectively, while that of PHEA-EDA-PLA was found to be 0.60 ± 0.05 mol%. Size exclusion chromatography (SEC) analysis confirmed the occurrence of derivatization, the molecular weight values being close to the theoretical ones. Polymeric micelles from PHEA-EDA-PLA and PHEA-EDA-PS(80)-PLA copolymers were obtained by using the dialysis method and were characterized in terms of mean size, zeta potential, critical aggregation concentration (CAC), and surface composition by x-ray photoelectron spectroscopy (XPS) analysis, which demonstrated the presence of PS(80) onto the PHEA-EDA-PS(80)-PLA micelle surface. In vitro experiments demonstrated that these systems had no cytotoxic effects on 16 HBE, Caco2, HuDe and K562 cell lines, and no haemolytic activity. Moreover, both PHEA-EDA-PS(80)-PLA and PHEA-EDA-PLA micelles were able to penetrate into Neuro2a cells and, in the case of PS(80) decorated micelles, to escape from phagocytosis by the J774 A1 macrophages.

Composite nanoparticles based on hyaluronic acid chemically cross-linked with alpha,beta-polyaspartylhydrazide.

In this paper, new composite nanoparticles based on hyaluronic acid (HA) chemically cross-linked with alpha,beta-polyaspartylhydrazide (PAHy) were prepared by the use of a reversed-phase microemulsion technique. HA-PAHy nanoparticles were characterized by FT-IR spectroscopy, confirming the occurrence of the chemical cross-linking, dimensional analysis, and transmission electron micrography, showing a sub-micrometer size and spherical shape. Zeta potential measurements demonstrated the presence of HA on the nanoparticle surface. A remarkable affinity of the obtained nanoparticles toward aqueous media that simulate some biological fluids was found. Stability studies showed the absence of chemical degradation in various media, while in the presence of hyaluronidase, a partial degradation occurred. Cell compatibility was evaluated by performing in vitro assays on human chronic myelogenous leukaemia cells (K-562) chosen as a model cell line and a haemolytic test. HA-PAHy nanoparticles were also able to entrap 5-fluorouracil, chosen as a model drug, and release it in a simulated physiological fluid and in human plasma with a mechanism essentially controlled by a Fickian diffusion.

Evaluation of the interaction and drug release from alpha,beta-polyaspartamide derivatives to a biomembrane model.

This article reports on a comparative study on the ability of various polymers, containing hydrophilic and/or hydrophobic groups, to interact with a biomembrane model using the differential scanning calorimetry (DSC) technique. Multilamellar vesicles of mixed dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidic acid (DMPA) were chosen as a model of cell membranes. The investigated samples were a water soluble polymer, the alpha,beta-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA) and its derivatives partially functionalized with polyethylene glycol (PEG2000) to obtain PHEA-PEG2000, with hexadecylamine (C16) to obtain PHEA-C16, and with both compounds to obtain PHEA-PEG2000-C16. These polymers are potential candidates to prepare drug delivery systems. In particular, some samples give rise to polymeric micelles able to entrap hydrophobic drugs in an aqueous medium. The migration of drug molecules from these micelles to DMPC/DMPA vesicles also has been evaluated by DSC analysis, by using ketoprofen as a model drug.