Abstract in Japanese

Within the current study, a delivery system based on a novel polymer-lectin conjugate (carbopol-lectin) was evaluated for the oral delivery of therapeutic peptides and proteins. It was demonstrated that covalent attachment of lectin to carbopol does neither decrease nor abolish the specific binding properties of lectin. Bioadhesion studies revealed that liposomes coated with carbopol lectin are more bioadhesive than liposomes coated with unmodified carbopol. Finally, the in vivo data suggest that carbopol-lectin conjugate coated liposomes are effective oral peptide delivery systems which are capable of increasing the pharmacological effect of orally administered calcitonin.

A novel thiomer derivative of glycol chitosan (GCS) was synthesized by coupling with thioglycolic acid (TGA) and evaluated for the pulmonary delivery of peptides. Nanoparticles (NPs) based on GCS and GCS-TGA were obtained by the ionic gelation method and demonstrated a particle size in the range of 0.23-0.33 μm with positive surface charge and high calcitonin entrapment. Fluorescent GCS-TGA NPs resulted in a 2-fold increase in mucoadhesion to lung tissue after intra-tracheal administration to rats as compared to non thiolated NPs. Evaluation of pulmonary toxicity revealed the biocompatibility of the two nanoparticulate formulations with lung tissue. The efficacy of the prepared NPs to enhance the pulmonary absorption of peptides was evaluated after pulmonary administration to rats using a liquid micro-sprayer technique. Calcitonin-loaded GCS and GCS-TGA NPs resulted in a pronounced hypocalcemic effect for at least 12 and 24 h, and a corresponding pharmacological availability of 27 and 40%, respectively. These findings suggest that both GCS and its thiomer derivative are promising and safe carriers for pulmonary peptide delivery.

The feasibility of combining safe permeation enhancers in a mucoadhesive particulate system for the oral delivery of peptide drugs was investigated in this study. Polyelectrolyte complex nanoparticles (NPs) were prepared by ionic interaction of spermine (SPM) with polyacrylic acid (PAA) polymer. Cytotoxicity studies in Caco-2 monolayers revealed the safety of the delivery system in the concentration range used for permeation enhancement. The cellular transport of fluorescein isothiocyanate dextran (FD4) showed higher permeation enhancing profiles of SPM-PAA NPs, as compared to SPM solution or PAA NPs prepared by ionic gelation with MgCl2 (Mg-PAA NPs). These permeation enhancing effects were associated with a reversible decrease in TEER values, suggesting a paracellular permeation pathway by reversible opening of the tight junctions. Furthermore, confocal microscopy results revealed strong association of the NPs prepared using fluorescence labeled PAA to Caco-2 cells. The permeation enhancing properties of SPM-PAA NPs were further evaluated in vivo after oral administration to rats, using FD4 and calcitonin as models of poorly permeating drugs. Confocal microscopy images of rats’ small intestine confirmed previous findings in Caco-2 cells and revealed a strong and prolonged penetration of FD4 from the mucosal to the basolateral side of the intestinal wall. In addition, the proposed NPs were efficient in improving the oral absorption of calcitonin, as evidenced by the significant and prolonged reduction of the blood calcemia in rats.

The utility of wild-type and variant carboxymethylproline synthases for biocatalysis was demonstrated by preparing functionalised 5-, 6- and 7-membered N-heterocycles from amino acid aldehydes and (alkylated) malonyl-coenzyme A derivatives; the N-heterocycles produced were converted to the corresponding bicyclic β-lactams by a carbapenem synthetase.

Formaldetected: Application of 1H- and 1D 13C HSQC NMR spectroscopy methods for monitoring the activity of a 2-oxoglutarate dependent histone Nε-methyllysine demethylase (JMJD2E) enabled the in situ quantitative analysis of the different components of the reaction, including the direct observation of hydrated formaldehyde resulting from enzyme-catalysed demethylation.