In Vitro Structural and Functional Evaluation of Gold Nanoparticles Conjugated Antibiotics

Bactericidal efficacy of gold nanoparticles conjugated with ampicillin, streptomycin and kanamycin were evaluated. Gold nanoparticles (Gnps) were conjugated with the antibiotics during the synthesis of nanoparticles utilizing the combined reducing property of antibiotics and sodium borohydride. The conjugation of nanoparticles was confirmed by dynamic light scattering (DLS) and electron microscopic (EM) studies. Such Gnps conjugated antibiotics showed greater bactericidal activity in standard agar well diffusion assay. The minimal inhibitory concentration (MIC) values of all the three antibiotics along with their Gnps conjugated forms were determined in three bacterial strains,Escherichia coli DH5α,Micrococcus luteusandStaphylococcus aureus. Among them, streptomycin and kanamycin showed significant reduction in MIC values in their Gnps conjugated form whereas; Gnps conjugated ampicillin showed slight decrement in the MIC value compared to its free form. On the other hand, all of them showed more heat stability in their Gnps conjugated forms. Thus, our findings indicated that Gnps conjugated antibiotics are more efficient and might have significant therapeutic implications

Atorvastatin calcium loaded chitosan nanoparticles: in vitro evaluation and in vivo pharmacokinetic studies in rabbits

In this study, we prepared atorvastatin calcium (AVST) loaded chitosan nanoparticles to improve the oral bioavailability of the drug. Nanoparticles were prepared by solvent evaporation technique and evaluated for its particle size, entrapment efficiency, zeta potential, in vitro release and surface morphology by scanning electron microscopy (SEM). In addition, the pharmacokinetics of AVST from the optimized formulation (FT5) was compared with marketed immediate release formulation (Atorva(r)) in rabbits. Particle size of prepared nanoparticles was ranged between 179.3 ± 7.12 to 256.8 ± 8.24 nm with a low polydispersity index (PI) value. Zeta potential study showed that the particles are stable with positive values between 13.03 ± 0.32 to 46.90 ± 0.49 mV. FT-IR studies confirmed the absence of incompatibility of AVST with excipient used in the formulations. In vitro release study showed that the drug release was sustained for 48 h. Results of pharmacokinetics study showed significant changes in the pharmacokinetic parameter (2.2 fold increase in AUC) of the optimized formulation as compared to marketed formulation (Atorva(r)). Thus, the developed nanoparticles evidenced the improvement of oral bioavailability of AVST in rabbit model.</p

A polysorbate-based non-ionic surfactant can modulate loading and release of beta-lactoglobulin entrapped in multiphase poly(DL-lactide-co-glycolide) microspheres

Purpose. The goal of the present paper was to investigate the role of a surfactant, Tween 20, in the modulation of the entrapment and release of beta-lactoglobulin (BLG) from poly (DL-lactide-co-glycolide) microspheres. Methods. Poly(DL-lactide-co-glycolide) microspheres containing BLG were prepared by a water-in-oil-in-water emulsion solvent procedure. Tween 20 was used as a surfactant in the internal aqueous phase of the primary emulsion. BLG entrapment efficiency and burst release were determined. Displacement of BLG from microsphere surface was followed by confocal microscopy observations and zeta potential measurements, whereas morphological changes were observed by freeze-fracture electron microscopy. Results. Tween 20 was shown to increase 2.8 fold the encapsulation efficiency of BLG without any modification of the stability of the first emulsion and the viscosity of the internal aqueous phase. In fact, Tween 20 was shown to be responsible for removing the BLG molecules that were adsorbed on the particle surface or very close to the surface as shown by confocal microscopy and zeta potential measurements. Tween 20 reduced the number of aqueous channels between the internal aqueous droplets as well as those communications with the external medium. Thus, the more dense structure of BLG microspheres could explain the decrease of the burst release. Conclusions, These results constitute a step forward in the improvement of existing technology in controlling protein encapsulation and delivery from microspheres prepared by the multiple emulsion solvent evaporation method

Alginate/Chitosan Nanoparticles are Effective for Oral Insulin Delivery

Abstract Purpose To evaluate the pharmacological activity of insulin-loaded alginate/chitosan nanoparticles following oral dosage in diabetic rats. Methods Nanoparticles were prepared by ionotropic pre-gelation of an alginate core followed by chitosan polyelectrolyte complexation. In vivo activity was evaluated by measuring the decrease in blood glucose concentrations in streptozotocin induced, diabetic rats after oral administration and flourescein (FITC)-labelled insulin tracked by confocal microscopy. Results Nanoparticles were negatively charged and had a mean size of 750 nm, suitable for uptake within the gastrointestinal tract due to their nanosize range and mucoadhesive properties. The insulin association efficiency was over 70% and insulin was released in a pH-dependent manner under simulated gastrointestinal conditions. Orally delivered nanoparticles lowered basal serum glucose levels by more than 40% with 50 and 100 IU/kg doses sustaining hypoglycemia for over 18 h. Pharmacological availability was 6.8 and 3.4% for the 50 and 100 IU/kg doses respectively, a significant increase over 1.6%, determined for oral insulin alone in solution and over other related studies at the same dose levels. Confocal microscopic examinations of FITC-labelled insulin nanoparticles showed clear adhesion to rat intestinal epithelium, and internalization of insulin within the intestinal mucosa. Conclusion The results indicate that the encapsulation of insulin into mucoadhesive nanoparticles was a key factor in the improvement of its oral absorption and oral bioactivity

Encapsulation of Hydrophilic and Lipophilic Compounds in Nanosomes Produced with a Supercritical Based Process

Liposomes are created when phospholipids self-assemble in an aqueous medium creating spherical closed structures. These vesicles can be loaded with hydrophilic active principles (AP) into the aqueous inner core or with lipophilic compounds in the lipidic double layer. In this work a new supercritical based process for the one-step continuous production of nanosomes is proposed for the encapsulation of hydrophilic and lipophilic compounds. This process is called Supercritical Assisted Liposome Formation (SuperLip). The innovation of this process consists in the inversion of the traditional phases of production of liposomes: water droplets are created by a spray atomization in a high pressure vessel, and then a double layer of phospholipids fast surrounds them. A systematic study on liposome size, morphology, encapsulation efficiency has been performed for several different hydrophilic AP (ampicillin, ofloxacin, bovine serum albumin, fluorescein, eugenol and theophylline). Some operative parameters were also optimized to achieve the production of nanometric liposomes with high encapsulation efficiencies. Operating in this way nanometric and monodispersed liposome suspensions were produced with EE up to 99%. To complete the study, other lipidic compounds were entrapped in the double lipidic layer, obtaining high entrapment efficiencies (TE), also in this case, up to 84.9%