It was aim of the study to investigate the in vivo potential of a novel insulin-thiomer complex nanoparticulate delivery system. Insulin loaded nanoparticles were obtained by the formation of hydrogen bonds between poly(vinyl pyrrolidone) (PVP) and poly(acrylic acid)-cysteine (PAA-Cys) or poly(acrylic acid) (PAA), respectively, in the presence of insulin. Dissolution behavior of insulin from tablets as well as nanoparticulate suspensions was evaluated in vitro. Serum insulin concentrations and reduction of blood sugar values were determined after oral administration of nanoparticles formulated as enteric coated tablets and suspensions. Results displayed a low serum insulin concentration and pharmacological efficacy in terms of blood sugar reduction after oral administration of enteric coated tablets. On the contrary, nanoparticulate suspensions led to significant serum insulin concentrations. Furthermore a 2.3-fold improvement of the AUC of insulin could be achieved due to the use of thiolated PAA instead of unmodified PAA. In addition, a blood sugar reduction of 22% was observed. Results demonstrate that this novel complex nanoparticulate formulation is an encouraging new attempt toward the noninvasive delivery of peptide drugs.
Except thyme oil and Miglyol 840, all tested oils caused an increase in CBF. Interestingly, the 0.2% concentrations of essential oils resulted in stronger effects when compared with the 2% concentrations.
In this study the preparation and stabilization of poly(acrylic acid)-cysteine nanoparticles and incorporation of a fluorescence marked model-compound was investigated. Nanoparticles were prepared by ionic gelation of a poly(acrylic acid)-cysteine conjugate with calcium chloride. Poly(acrylic acid)-cysteine nanoparticles display high cohesive properties due to a cross-linking process via calcium bridges in the core and the pervasive formation of disulphide bonds and were 139 ± 34 nm in size. Nanoparticles were loaded with FITC-dextrans (flourescein isothiocyanate-dextrans) of 4, 20 and 40 kDa molecular mass as model-compound via sonication method or via vibration method for 3 and 24 h. In vitro release studies showed an initial burst release followed by an extended release of model-compounds. The lower the molecular mass of the FITC-dextrans, the higher was the amount of incorporated and released model compounds. Vibration seems to be a proper method for the incorporation of hydrophilic and macromolecular drugs in poly(acrylic acid)-cysteine nanoparticles.
The present study focused on the assembly of an insulin exhibiting, nanoparticulate formulation and the characterization thereof regarding particle size, zeta potential and stability of nanoparticles as well as mucoadhesion indicating, turbidity measurements and drug release studies after particle purification. The preparation was performed in the presence of insulin due to the formation of hydrogen bonds between poly(vinyl pyrrolidone) (PVP) and poly(acrylic acid) (PAA) or its conjugate poly(acrylic acid)-cysteine (PAA-Cys) with a molecular mass of 100 as well as 450 kDa. Stable suspensions, displaying nanoparticles with a mean particle size in the range of 200 nm as well as a negative zeta potential, were achieved with 100 kDa poly(acrylic acid) (PAA100) or poly(acrylic acid)-cysteine (PAA100-Cys). Turbidity measurements displayed a pH dependent interaction of nanoparticulate material and mucin leading to a greater and earlier interference at pH 3.9 compared to pH 7.4. Moreover a 1.2-fold increase of the absorbance of nanoparticle-mucin dispersions compared to mucin control was observed after 3 h. The introduced particulate drug delivery system might in conclusion display a sophisticated vehicle for the non-invasive delivery of insulin and other peptide drugs.
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