Green Routes for Bio-Fabrication in Biomedical and Pharmaceutical Applications.

In the last decade, significant advances in nanotechnologies, rising from increasing knowledge and refining of technical practices in green chemistry and bioengineering, enabled the design of innovative devices suitable for different biomedical applications. In particular, novel bio-sustainable methodologies are developing to fabricate drug delivery systems able to sagely mix properties of materials (i.e., biocompatibility, biodegradability) and bioactive molecules (i.e., bioavailability, selectivity, chemical stability), as a function of the current demands for the health market. The present work aims to provide an overview of recent developments in the bio-fabrication methods for designing innovative green platforms, emphasizing the relevant impact on current and future biomedical and pharmaceutical applications.

Improving in vivo oral bioavailability of a poorly soluble drug: a case study on polymeric versus lipid nanoparticles.

Poorly soluble drugs must be appropriately formulated for clinical use to increase the solubility, dissolution rate, and permeation across the intestinal epithelium. Polymeric and lipid nanocarriers have been successfully investigated for this aim, and their physicochemical properties, and in particular, the surface chemistry, significantly affect the pharmacokinetics of the drugs after oral administration. In the present study, PLGA nanoparticles (SS13NP) and solid lipid nanoparticles (SS13SLN) loaded with SS13, a BCS IV model drug, were prepared. SS13 bioavailability following the oral administration of SS13 (free drug), SS13NP, or SS13SLN was compared. SS13NP had a suitable size for oral administration (less than 300 nm), a spherical shape and negative zeta potential, similarly to SS13SLN. On the contrary, SS13NP showed higher physical stability but lower encapsulation efficiency (54.31 ± 6.66%) than SS13SLN (100.00 ± 3.11%). When orally administered (0.6 mg of drug), SS13NP showed higher drug AUC values with respect to SS13SLN (227 ± 14 versus 147 ± 8 µg/mL min), with higher Cmax (2.47 ± 0.14 µg/mL versus 1.30 ± 0.15 µg/mL) reached in a shorter time (20 min versus 60 min). Both formulations induced, therefore, the oral bioavailability of SS13 (12.67 ± 1.43% and 4.38 ± 0.39% for SS13NP and SS12SLN, respectively) differently from the free drug. These in vivo results confirm that the chemical composition of nanoparticles significantly affects the in vivo fate of a BCS IV drug. Moreover, PLGA nanoparticles appear more efficient and rapid than SLN in allowing drug absorption and transport to systemic circulation.

Electron dispersive X-ray spectroscopy and degradation properties of hyaluronic acid decorated microparticles.

The purpose of this study was to produce poly(DL-lactic-co-glycolic acid) (PLGA) - based microparticles (MPs), externally decorated with hyaluronic acid (HA). The MPs are intended for intravitreal injections in the treatment of posterior eye segment and have been designed to prolong the release of growth factors into the vitreous body, therefore aiming to increase the time interval between two consecutive injections. The MPs, prepared by a modified double emulsion-solvent evaporation technique and loaded with bovine serum albumins (BSA) and ciliary neurotrophic factor (CNTF), were spherical, with a diameter around 70 µm and a >90% encapsulation efficiency. Energy Dispersive Spectroscopy (EDS) outcomes indicated that HA presence in the external aqueous phase of the emulsion did affect the surface properties of MPs. Moreover, poloxamers drastically slowed down MP degradation properties which are, in turn, closely related to their ability to prolong drug release. This is promising for the envisaged application of the produced MPs. Further work will be devoted to optimizing MP formulation with respect to the envisaged intravitreal route of administration.

Combination therapy for the treatment of pancreatic cancer through hyaluronic acid-decorated nanoparticles loaded with quercetin and gemcitabine: A preliminary in vitro study.

Combination chemotherapy by means of two or more drugs is prone to suppressing or discouraging the inception of multidrug resistance, exploiting the fact that diverse drugs act in different points of the cellular cycle of amplifying tumor cells. For example, the combination of gemcitabine (GMC) with quercetin (QCT) showed a synergistic effect in inhibiting the migration of pancreatic cancer cells. Consequently, herein GMC and QCT have been loaded within biodegradable nanoparticles (NPs) based on poly(lactic-co-glycolic acid), externally decorated with hyaluronic acid (HA; viz., PPHA NPs), which plays a major role in drug targeting to tumors due to its ability to specifically interact with CD44 receptor, that is overexpressed in many tumors. The produced HA-decorated NPs loaded with GMC and QCT showed an improved cytotoxicity and cellular uptake toward two cell lines of pancreatic ductal adenocarcinoma, namely Mia-PaCa-2 and PANC-1, compared with both the bare drugs and the drugs loaded in NPs which do not expose HA on the surface. HA-decorated NPs were also able to improve the anti-inflammatory properties of QCT, therefore leading to a decrease of interleukin cellular levels in both cell lines, preliminarily stimulated with lipopolysaccharides. This result is of special interest also considering the crucial role of interleukins in progression, metastatic processes, and drug resistance of human pancreas cancer cells.

Nano-precipitated curcumin loaded particles: effect of carrier size and drug complexation with (2-hydroxypropyl)-ß-cyclodextrin on their biological performances.

In this work, curcumin (CURC)-encapsulating nanoparticles (NPs), made up of an amphiphilic blend of poloxamers and PLGA (PPC NPs) at different polymer concentrations, were prepared by nanoprecipitation. CURC was preliminarily complexed with (2-hydroxypropyl)-ß-cyclodextrin (HPßCD) to improve its loading efficiency. The formation of host-guest complexes of CURC with HPßCD (CD-CURC) was confirmed by means of 1HNMR studies and differential scanning calorimetry (DSC). Nanoprecipitation allowed to obtain NPs with a small size (90-120nm depending on the polymer concentration), a narrow size distribution and stable in water for 30days at 4°C and in RPMI-1640 cell culture medium up to 72h at 37°C. The in vitro release of CD-CURC, sustained up to 5days, was governed mainly by a diffusive mechanism. It was also found that the produced NPs were efficiently internalized by mesothelioma cells (MSTO-211H) in the cytoplasmic space, at an extent strongly dependent on NP size and polydispesity index, therefore pointing at the importance of NP preparation method in improving their uptake.

Surface modified zeolite-based granulates for the sustained release of diclofenac sodium.

In this study, a granulate for the oral controlled delivery of diclofenac sodium (DS), an anionic sparingly soluble nonsteroidal anti-inflammatory drug, has been realized by wet granulation, using a surface modified natural zeolite (SMNZ) as an excipient. The surface modification of the zeolite has been achieved by means of a cationic surfactant, so as to allow the loading of DS through ionic interaction and bestow a control over the drug release mechanism. The granules possessed a satisfactory dosage uniformity, a flowability suitable for an oral dosage form manufacturing, along with a sustained drug release up to 9h, driven by both ion exchange and transport kinetics. Furthermore, the obtained granulate did not elicit a significant cytotoxicity and could also induce a prolonged anti-inflammatory effect on RAW264.7 cells. Taking also into account that natural zeolites are generally abundant and economic, SMNZ can be considered as an attracting alternative excipient for the production of granules with sustained release features.

Spontaneous arrangement of a tumor targeting hyaluronic acid shell on irinotecan loaded PLGA nanoparticles.

The arrangement of tumor targeting hyaluronic acid (HA) moieties on irinotecan (IRIN)-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) has been directed by means of a gradient of lipophilicity between the oil and water phases of the emulsion used to produce the NPs. PLGA constitutes the NP bulk while HA is superficially exposed, with amphiphilic poloxamers acting as a bridge between PLGA and HA. Differential scanning calorimetry, zeta potential analyses and ELISA tests were employed to support the hypothesis of polymer assembly in NP formulations. The presence of flexible HA chains on NP surface enhances NP size stability over time due to an increased electrostatic repulsion between NPs and a higher degree of hydration of the device surface. IRIN in vitro release kinetics can be sustained up to 7-13 days. In vitro biologic studies indicated that HA-containing NPs were more toxic than bare PLGA NPs against CD44-overexpressing breast carcinoma cells (HS578T), therefore indicating their ability to target CD44 receptor.

Surface modified natural zeolite as a carrier for sustained diclofenac release: A preliminary feasibility study.

In view of zeolite potentiality as a carrier for sustained drug release, a clinoptilolite-rich rock from California (CLI_CA) was superficially modified with cetylpyridinium chloride and loaded with diclofenac sodium (DS). The obtained surface modified natural zeolites (SMNZ) were characterized by confocal scanning laser microscopy (CLSM), powder X-ray diffraction (XRPD) and laser light scattering (LS). Their flowability properties, drug adsorption and in vitro release kinetics in simulated intestinal fluid (SIF) were also investigated. CLI_CA is a Na- and K-rich clinoptilolite with a cationic exchange ability that fits well with its zeolite content (clinoptilolite=80 wt%); the external cationic exchange capacity is independent of the cationic surfactant used. LS and CLSM analyses have shown a wide distribution of volume diameters of SMNZ particles that, along with their irregular shape, make them cohesive with scarce flow properties. CLSM observation has revealed the localization of different molecules in/on SMNZ by virtue of their chemical nature. In particular, cationic and polar probes prevalently localize in SMNZ bulk, whereas anionic probes preferentially arrange themselves on SMNZ surface and the loading of a nonpolar molecule in/on SMNZ is discouraged. The adsorption rate of DS onto SMNZ was shown by different kinetic models highlighting the fact that DS adsorption is a pseudo-second order reaction and that the diffusion through the boundary layer is the rate-controlling step of the process. DS release in an ionic medium, such as SIF, can be sustained for about 5h through a mechanism prevalently governed by anionic exchange with a rapid final phase.

Curcumin loaded PLGA-poloxamer blend nanoparticles induce cell cycle arrest in mesothelioma cells.

The pharmacological potential of curcumin (CURC) is severely restricted because of its low water solubility/absorption, short half-life and poor bioavailability. To overcome these issues, CURC-loaded nanoparticles (NPs) were produced by a double emulsion technique. In particular, NPs were made up of an amphiphilic blend of poloxamers and PLGA to confer stealth properties to the NPs to take advantage of the enhanced permeability and retention (EPR) effect. Different surface properties of NPs made up of bare PLGA and PLGA/poloxamer blend were confirmed by the different interactions of these NPs with serum proteins and also by their ability to be internalized by mesothelioma cell line. The uptake of PLGA/poloxamer NPs induces a persistent block in G0/G1 phase of the cell cycle up to 72 h, thus overcoming the drug tolerance phenomenon, normally evidenced with free CURC.

Design of electrospayed non-spherical poly (L-lactide-co-glicolide) microdevices for sustained drug delivery.

Polymer chain entanglements in organic solvents can be considered a key parameter in the formation of non-spherical beads when electrospraying is employed. The shape of micro/nanometric drug delivery systems plays a major role since it can affect circulation, extravasation, distribution and in vivo clearance of the devices. In this frame, we investigated the influence of polymer processing parameters on the design of polylactic-co-glycolic acid non-spherical microdevices loaded with triamcinolone acetonide (TrA), a sparingly water soluble corticosteroid, prepared by electrospraying technique through a one-step process. In particular, we verified that the formation of non-spherical MDs is related to the presence of entanglements among polymer chains to select the optimal solution to be sprayed. The addition of TrA did not substantially affect the particle morphology in terms of size, size distribution and circularity at all the tested drug loadings. Furthermore, the drug could be released for a prolonged period, with controlled and reproducible kinetics for over 3 weeks. The mathematical modeling of release profiles highlighted that the release is mainly driven by degradation, at a higher extent in the case of low drug loading.