A new pollen-derived microcarrier for pantoprazole delivery.

Plant-derived carriers have emerged as promising materials for drug encapsulation. Especially, sporopollenin microcapsules extracted from diverse pollen species have been proved to be effective drug carriers due to their biocompatibility, homogeneity in size, resistance to harsh chemical conditions and high thermal stability. Here in this study, sporopollenin microcapsules were isolated successfully from the pollens of a common tree (Corylus avellana, the European hazelnut) and used as a carrier for pantoprazole (PaNa) (a proton pump inhibitor). The drug entrapment efficiency was recorded as 29.81%. SEM micrographs clearly showed the drug was loaded into the microcapsules through the apertures of microcapsule and also some drugs were adsorbed on the surface of microcapsules. FT-IR spectra analysis confirmed the drug loading. Thermogravimetric analysis revealed that thermal stability of PaNa was enhanced by encapsulation. In vitro release studies showed that PaNa-loaded sporopollenin microcapsules exhibited better release performance than the control. C. avellana sporopollenin microcapsules can make an efficient carrier for delivery of PaNa.

Reaction of proton pump inhibitors with model peptides results in novel products.

The proposed mechanism for proton pump inhibitors (PPIs) is that PPIs are activated at low pH to the sulfenamide form, which reacts with the sulfhydryl group of cysteine(s) at the active site of the proton pump, to produce reducible disulfide-bonded PPI-proton pump conjugates. However, this mechanism cannot explain the observations that some PPI-protein conjugates are irreducible. This study was designed to investigate the chemistry of the irreducible conjugates by mass spectrometry, using three PPIs and 17 cysteine-containing peptides. While some peptides favored the formation of reducible PPI-peptide adduct, the other peptides mainly produced irreducible adducts. Characterization of the irreducible adduct revealed that the irreducible bonding required the participation of both a sulfhydryl group and a nearby primary amino group. High resolution mass spectrometry suggested a molecular structure of the irreducible adduct. These results suggested a reaction mechanism in which the PPI pyridone form reacted with an amino group and a sulfhydryl group to form an irreducible adduct. The irreducible adduct becomes the dominant product over time because of the irreversible nature of the pyridone-mediated reaction. These findings may explain the irreducible inhibition of H/K-ATPase by PPIs and their relatively slow biological turnover in vivo. [Supplementary materials: available only at http://dx.doi.org/10.1254/jphs.13058FP].

Agglomerates containing pantoprazole microparticles: modulating the drug release.

Pantoprazole-loaded microparticles were prepared using a blend of Eudragit S100 and Methocel F4M. The accelerated stability was carried out during 6 months at 40 degrees C and 75% relative humidity. In order to improve technological characteristics of the pantoprazole-loaded microparticles, soft agglomerates were prepared viewing an oral delayed release and gastro-resistant solid dosage form. The agglomeration was performed by mixing the pantoprazole microparticles with spray-dried mannitol/lecithin powders. The effects of factors such as the amount of lecithin in the spray-dried mannitol/lecithin powders and the ratio between pantoprazole microparticles and spray-dried mannitol/lecithin powders were evaluated. The pantoprazole-loaded microparticles present no significant degradation in 6 months. The agglomerates presented spherical shape, with smooth surface and very small quantity of non-agglomerated particles. The agglomerates presented different yields (35.5-79.0%), drug loading (58-101%), and mechanical properties (tensile strength varied from 44 to 69 mN mm(-2)), when the spray-dried mannitol/lecithin powders with different lecithin amounts were used. The biopharmaceutical characteristics of pantoprazole microparticles, i.e., their delayed-release properties, were not affected by the agglomeration process. The gastro-resistance of the agglomerates was affected by the amount of spray-dried mannitol/lecithin powders. The ratio of lecithin in the spray-dried mannitol/lecithin powders was the key factor in the agglomerate formation and in the drug release profiles. The agglomerates presenting better mechanical and biopharmaceutical characteristics were prepared with 1:2 (w/w) ratio of pantoprazole-loaded microparticles and mannitol/lecithin (80:20) powder.

Transport through liquid membranes containing omeprazole and lansoprazole.

Omeprazole and lansoprazole, the therapeutically important drugs belonging to proton pump inhibitor category are extensively used in the treatment of gastric ulcers. Transport through liquid membranes generated by these drugs in lecithin-cholesterol mixture in series with a supporting membrane has been studied. The data obtained show the formation of liquid membrane in series with the supporting membrane. Transport of cations, chloride and bicarbonate ions in the presence liquid membranes generated by omeprazole and lanzoprazole indicate the modification in the permeability of various permeants.