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The aim of this work was the assessment of the “in vivo” immune response of a poly(lactide-co-glycolide)-based nanoparticulate adjuvant for a sub-unit vaccine, namely, a purified recombinant collagen-binding bacterial adhesion fragment (CNA19), againstStaphylococcus aureus-mediated infections. “In vivo” immunogenicity studies were performed on mice: immunisation protocols encompassed subcutaneous and intranasal administration of CNA19 formulated as nanoparticles (NPs) and furthermore, CNA19-loaded NPs formulated in a set-up thermosetting chitosan-β-glycerolphosphate (chitosan-β-GP) solution for intranasal route in order to extend antigen exposure to nasal mucosa. CNA19 loaded NPs (mean size of about 195 nm, 9.04 ± 0.37μg/mg as CNA19 loading capacity) confirmed as suitable vaccine for subcutaneous administration with a more pronounced adjuvant effect (about 3-fold higher) with respect to aluminium, recognised as “reference” adjuvant. CNA19 loaded NPs formulated in an optimised thermogelling chitosan-β-GP solution showed promising results for eliciting an effective humoral response and a good chance as intranasal boosting dose. [ABSTRACT FROM PUBLISHER]

Ovarian follicle encapsulation in synthetic or natural matrixes based on biopolymers is potentially a promising approach toin vitromaturation (IVM) process, since it maintains follicle 3D organisation by preventing its flattening and consequent disruption of gap junctions, preserving the functional relationship between oocyte and companion follicle cells. The aim of the work was to optimise physico-chemical parameters of alginate microcapsules for perspective IVM under 3D environments. On this purpose alginate and cross-linking agent concentrations were investigated. Alginate concentration between 0.75% and 0.125% w/w and Mg2+, Ba2+, Ca2+ at concentration between 100 and 20 mM were tested. Follicle encapsulation was obtained by on purpose modified diffusion setting gelation technique, and evaluated together with beads, chemical and mechanical stability in standard and stressing conditions. Beads permeability was tested towards albumin, fetuin, pyruvate, glucose, pullulan. Results demonstrated that 0.25% alginate cross-linked in 100 mM CaCl2beads is suitable to follicle encapsulation. [ABSTRACT FROM AUTHOR]

The aim was to design sterile biodegradable microparticulate drug delivery systems based on poly( dl-lactide) (PLA) and poly(ϵ-caprolactone) (PCL) and containing ivermectin (IVM), an antiparasitic drug, for subcutaneous administration in dogs. The drug delivery system should: (i) ensure a full 12-month protection upon single dose administration; (ii) be safe with particular attention regarding IVM dosage and its release, in order to prevent over dosage side effects. This preliminary work involves: polymer selection, evaluation of the effects of γ-irradiation on the polymers and IVM, investigation and set up of suitable microparticle preparation process and parameters, IVM-loaded microparticles in vitro release evaluation. Results of gel permeation chromatography analysis on the irradiated polymers and IVM mixtures showed that combination of IVM with the antioxidant α-tocopherol (TCP) reduces the damage extent induced by irradiation treatment, independently on the polymer type. Solvent evaporation process was successfully used for the preparation of PLA microparticles and appropriately modified; it was recognized as suitable for the preparation of PCL microparticles. Good process yields were achieved ranging from 76.08% to 94.72%; encapsulation efficiency was between 85.76% and 91.25%, independently from the polymer used. The type of polymer and the consequent preparation process parameters affected microparticle size that was bigger for PCL microparticles (480-800 µm) and solvent residual that was >500 ppm for PLA microparticles. In vitro release test showed significantly faster IVM release rates from PCL microparticles, with respect to PLA microparticles, suggesting that a combination of the polymers could be used to obtain the suitable drug release rate. [ABSTRACT FROM AUTHOR]

Introduction: The goal of the present work was to evaluate and discuss vibration nozzle microencapsulation (VNM) technology combined to lyophilization, for the microencapsulation of a hydrophilic model molecule into a hydrophilic polymer. Materials and methods: Fluorescein-loaded alginate microparticles prepared by VNM and emulsion phase inversion microencapsulation (EPIM) were lyophilized. Morphology, particle size distribution, lyophilized microspheres stability upon rehydration, drug loading and in vitro release were evaluated. Results and discussion: Well-formed microspheres were obtained by the VNM technique, with higher yields of production (93.3-100%) and smaller particle size (d50138.10-158.00) than the EPIM microspheres. Rehydration upon lyophilization occurred in 30 min maintaining microsphere physical integrity. Fluorescein release was always faster from the microspheres obtained by VNM (364 h) than from those obtained by EPIM (504 h). Conclusion: The results suggest that VNM is a simple, easy to be scaled-up process suitable for the microencapsulation hydrophilic drugs. [ABSTRACT FROM AUTHOR]

Inhibition of osteoclasts by bisphosphonate is one strategy to be explored in order to avoid a revision surgery. The purpose of this preliminary work is to synthesize hydroxyapatite--alendronate (HA--ALN) composites as carrier for ALN that could improve its site specific activity. HA--ALN composites were prepared by the co-precipitation method. Process parameters such as HA:ALN w/w ratio (1:1, 5:1 and 10:1) and HA incubation times (6, 24, 48 and 72 h) were evaluated. Morphological, physical--chemical characterization and biocompatibility tests were performed. TEM and SEM analyses confirmed ALN precipitation as fine network onto HA. The results of physical--chemical characterization confirmed the presence of ALN in the composites and its interaction with HA. ALN content resulted between 60%% and 80%% in the HA:ALN 5:1 and 10:1 ratios composites. ALN release reached 80%% from HA--ALN 10:1 composites. Biological tests revealed that complexation with HA increased ALN biocompatibility by three times. These preliminary results demonstrated that HA--ALN composites could be considered a carrier to control ALN release. [ABSTRACT FROM AUTHOR]

A novel formulation based on chondroitin sulphate/chitosan microspheres (CS/CH) has been investigated for oral delivery of macromolecules using ovalbumin as the model protein (OVA). The microspheres were prepared by a new emulsion-complex coacervation method. Physico-chemical properties of the polymers constituting microparticulate matrix were investigated by IR, DSC, TGA and X-ray diffraction analyses. In vitro tests were performed to evaluate the drug delivery system degradation and the protein release under conditions simulating the intestinal fluids. The ability of colonic enzymes to degrade the microparticulate systems was simulated employing the chondroitinase ABC enzyme. Results showed that the different CS/CH compositions influenced both microparticles stability and the protein release rate. Only the microspheres composed by 1:1 chondroitin sulphate–chitosan ratio achieved an OVA release profile suitable to a possible colon targeting. These microspheres released ∼30% of ovalbumin encapsulated in 24 h in the different aqueous media tested, while they released 100% of protein in the presence of chondroitinase. The preliminary results demonstrated that chondroitin sulphate-chitosan microspheres can be a suitable delivery system for protein drug envisaged to oral administration. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the feasibility of exploiting ultrasonication coupled with ionotropic gelation in order to prepare tripolyphosphate (TPP)-chitosan glutamate nanoparticles suitable for the delivery of the enzyme prolidase. Methods: All the parameters for the preparation of TPP-chitosan nanoparticles in terms of components weight ratio, ultrasonication conditions and time-saving nanoparticles recovery conditions were optimized. The best formulation was loaded with the prolidase. All the nanoparticles were characterized in terms of morphology, size, polydispersity, zeta-potential, yield of the process and encapsulation efficiency. The in-vitro activity of the prolidase was assessed by capillary electrophoresis (CE). Results and conclusions: A TPP to chitosan weight ratio of 0.2:1 combined with one ultrasonication cycle (4 min using the probe-type sonifier at 75% power) obtained well-formed nanoparticles of spherical shape, mean size of ∼ 365 nm (polydispersity index 0.3) and a + 17.94 mV zeta potential. A satisfactory prolidase encapsulation efficiency (43%) was obtained with a yield of the preparation process of ∼55%. In vitro study of activity of prolidase, as free enzyme or released from chitosan nanoparticles, highlighted the ability of chitosan to stabilize the enzyme during all the steps of the preparation process and to modulate the enzyme activity up to 48 h. [ABSTRACT FROM AUTHOR]

Atomic force microscopy (AFM) is recognized a suitable and powerful technique for surface and morphological analysis. Even if until now this technique has not been frequently used in the pharmaceutical field, it can contribute to an accurate morphologic characterization of microspheres and nanospheres. In this work, atomic force microscopy has been used to perform the surface characterization of sterilized microspheres. The aim is to investigate the morphologic modifications induced by gamma irradiation on poly(lactide-co-glycolide) microspheres loaded with ovalbumin and to compare the results obtained by AFM to those obtained by scanning electron microscopy (SEM). The results obtained show that, with respect to SEM, AFM can give some additional information regarding the modifications induced by γ -irradiation on microspheres surface morphology. The significant changes in surface roughness after irradiation are indicative of damage due to γ -irradiation. The unchanged surface roughness values calculated for microspheres containing PEG in their matrix, suggest that this polymer exerts a protective effect towards γ -irradiation. [ABSTRACT FROM AUTHOR]

The purpose of this work was to study the encapsulation of bovine serum albumin (BSA) in polylactide-co-glycolide (PLGA) microspheres using an emulsion/ spray-drying method. Albumin was dissolved in an aqueous phase (w) in the presence of surfactant and emulsified in an organic phase containing the polymer (o). To stabilize the emulsion, different types of surfactant (Pluronic® F68, Pluronic F127, sodium oleate, dioctylsulfosuccinate) were added to the aqueous phase. The w/o emulsion was spray-dried to obtain BSA-loaded PLGA microspheres. The effect of type of surfactant on microsphere characteristics was evaluated. The microspheres were characterized for their morphology by scanning electron microscopy (SEM) and granulometric analysis; drug content determination and in vitro dissolution tests were performed. Results showed that the emulsion/spray-drying method is suitable for obtaining small microparticles (2-5 μm) characterized by high drug payloads (70%-80% encapsulation efficiency). The type of surfactant affects the microsphere shape and BSA release behavior. The purpose of this work was to study the encapsulation of bovine serum albumin (BSA) in polylactide-co-glycolide (PLGA) microspheres using an emulsion/ spray-drying method. Albumin was dissolved in an aqueous phase (w) in the presence of surfactant and emulsified in an organic phase containing the polymer (o). To stabilize the emulsion, different types of surfactant (Pluronic® F68, Pluronic F127, sodium oleate, dioctylsulfosuccinate) were added to the aqueous phase. The w/o emulsion was spray-dried to obtain BSA-loaded PLGA microspheres. The effect of type of surfactant on microsphere characteristics was evaluated. The microspheres were characterized for their morphology by scanning electron microscopy (SEM) and granulometric analysis; drug content determination and in vitro dissolution tests were performed. Results showed that the emulsion/spray-drying method is suitable for obtaining... [ABSTRACT FROM AUTHOR]