Application of Near-Infrared Spectrometry to Evaluate the Mechanism of Wet Granulation Using a High-Speed Mixer with Porous Calcium Silicate and Sugar Alcohols.

The current study examined the mechanism of wet granulation with a high-speed mixer using porous calcium silicate (PCS) as the excipient and low-molecular-weight sugar alcohols (erythritol, mannitol, maltitol, or xylitol) as the binder. Granules did not form when erythritol or mannitol was used as the binder. No major changes in X-ray powder diffraction data and near-infrared (NIR) spectroscopy spectra were noted when erythritol was used in granulation. Meanwhile, granules formed when xylitol was used as the binder. The NIR spectra of the obtained granules had a widened band near 5100 cm-1 due to hydroxyl groups. From the peak fitting near 4800 cm-1 using the Gaussian-Lorentzian product function, the contribution of hydrogen bonds in water species increased during granulation. The NIR spectra of these potential binders revealed a band of hydroxyl groups for intramolecular hydrogen bonds near 6900 cm-1 when maltitol or xylitol was used as the binder, whereas no band was observed for erythritol and mannitol. Changes in the NIR spectra assigned to water were useful in evaluating the progression of granulation as a process analytical technology. Moreover, X-ray powder diffraction illustrated that the peak due to xylitol crystals disappeared. Xylitol existed in an amorphous state in the granules, suggesting molecular interactions. Thus, hydroxyl groups in sugar alcohols facilitate hydrogen bonding between PCS (silanol groups) and molecules via water, and this is considered to be the mechanism by which granules are formed.

Photostable Solid Dispersion of Nifedipine by Porous Calcium Silicate.

Nifedipine (NIF) is a typical light-sensitive drug requiring protection from light during manufacture, storage, and handling of its dosage forms. The purpose of this study was to evaluate the utility of porous calcium silicate (PCS) for maintaining the photostability of NIF in a solid dispersion formulation. Adsorption solid dispersion (ASD) prepared using NIF and PCS as an amorphous formulation was more stable to light irradiation than a physical mixture of NIF and microcrystalline cellulose (a control physical mixture) as a crystalline formulation. In addition, PCS in physical mixtures with NIF adequately protected NIF from photodegradation, suggesting that this protective effect could be because of some screening effect by the porous structure of PCS blocking the passage of light reaching NIF in pores of PCS. These findings suggest that PCS is useful for improving the solubility and photostability of NIF in solid dispersion formulation.

Preparation and Evaluation of Solid Dispersion Tablets by a Simple and Manufacturable Wet Granulation Method Using Porous Calcium Silicate.

The aim of this study was to prepare and evaluate solid dispersion tablets containing a poorly water-soluble drug using porous calcium silicate (PCS) by a wet granulation method. Nifedipine (NIF) was used as the model poorly water-soluble drug. Solid dispersion tablets were prepared with the wet granulation method using ethanol and water by a high-speed mixer granulator. The binder and disintegrant were selected from 7 and 4 candidates, respectively. The dissolution test was conducted using the JP 16 paddle method. The oral absorption of NIF was studied in fasted rats. Xylitol and crospovidone were selected as the binder and disintegrant, respectively. The dissolution rates of NIF from solid dispersion formulations were markedly enhanced compared with NIF powder and physical mixtures. Powder X-ray diffraction (PXRD) confirmed the reduced crystallinity of NIF in the solid dispersion formulations. Fourier transform infrared (FT-IR) showed the physical interaction between NIF and PCS in the solid dispersion formulations. NIF is present in an amorphous state in granules prepared by the wet granulation method using water. The area under the plasma concentration-time curve (AUC) and peak concentration (C(max)) values of NIF after dosing rats with the solid dispersion granules were significantly greater than those after dosing with NIF powder. The solid dispersion formulations of NIF prepared with PCS using the wet granulation method exhibited accelerated dissolution rates and superior oral bioavailability. This method is very simple, and may be applicable to the development of other poorly water-soluble drugs.

Hop polyphenols suppress production of water-insoluble glucan by Streptococcus mutans and dental plaque growth in vivo.

OBJECTIVE: This study determined the effect of Hop polyphenols (HPP) on water-insoluble glucan (WIG), which is a major component of dental plaque along with microorganisms, and the effect of HPP-containing tablets on the growth of dental plaque. METHODS: The effects of HPP on Streptococcus mutans MT8148 were determined. HPP concentrations employed in this study were 0% (as the HPP control), 0.001%, 0.01%, 0.1%, and 0.5%. The average result of six independent experiments was obtained at each concentration of HPP. Suppression of plaque formation in vivo was examined by a clinical trial that was designed as a randomized, single-blind, three-treatment study using 28 healthy subjects. The subjects used either 20 mg or seven mg HPP-containing tablets representing high and low dosages, respectively. The composition of each tablet was similar, except for the level of HPP; the control tablet had none. For the treatment period, subjects took one tablet seven times a day (before breakfast, after each meal, between meals, and at bedtime) for three days. The tablets were dissolved in the mouth and naturally swallowed. Plaque levels were then assessed for the subjects in the three groups. RESULTS: In vitro, after 24-hour incubation, 0.5% HPP significantly reduced the growth of S. mutans compared to the control (p < 0.01). After 18-hour incubation, HPP at 0.1% and 0.5% significantly reduced lactic acid production (p < 0.05 and p < 0.001, respectively), and HPP at 0.01%, 0.1%, and 0.5% also suppressed WIG production (p < 0.01, p < 0.001 and p < 0.001, respectively). In vivo, the effect of HPP-containing tablets (seven times a day) on three-day dental plaque regrowth was assessed by the plaque scoring system (PSS). The high-dosage group using 20 mg HPP tablets exhibited a reduction in PSS (1.37 +/- 0.48 vs. 2.41 +/- 1.15 in the control group, p < 0.05). CONCLUSION: It was concluded that HPP tablets might be a significant means of delivering HPP onto tooth surfaces to prevent dental plaque formation.

Improvement of the agitation granulation method to prepare granules containing a high content of a very hygroscopic drug.

This study describes a new approach to the preparation of a granulate with a high content of a very hygroscopic powder or drug, using the agitation granulation method, and the development of a tablet formulation using these granulates. A Chinese medicine extract, Hatimi-zio-gan, was used as the model of a very hygroscopic drug. Among the several excipients tested, only porous calcium silicate could be used to prepare granules, with a mixing ratio (extract to porous calcium silicate) from 2:1 to 20:1. With other excipients, very large lumps were formed during the granulation process. The best mixing ratio of extract to porous calcium silicate was 6:1. For preparation of the granules, water could be added to the mixed powder within a range of 1- to 4-times the amount of porous calcium silicate. From these results, it was concluded that the ability of porous calcium silicate to hold large amounts of water in its numerous pores may allow for the preparation of granulates with a high content of very hygroscopic drugs. Starch with partial alpha-links, carboxymethyl starch sodium salt and crospovidone were used for selection of the disintegration agent. When crospovidone was used as a disintegration agent, tablets containing about 70% of the Chinese medicine extract disintegrated in less than 7 min, with good dissolution rates. The same process was applied to extracts of Hotyu-ekki-to, Syo-seiryu-to, Boi-ogi-to and Bohu-tusyo-san. The absorption of paeoniflorin, a characteristic monoterpene glucoside contained in Hatimi-zio-gan extract, was evaluated in beagle dogs after oral administration of the Hatimi-zio-gan tablets prepared in this study. The values of C(max) and AUC obtained after administration of the tablets prepared in this study were significantly greater than those obtained for commercial tablets.

In vivo expression of UDP-N-acetylglucosamine: Alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I (GnT-1) in Aspergillus oryzae and effects on the sugar chain of alpha-amylase.

UDP-N-Acetylglucosamine: alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I (GnT-I) is an essential enzyme in the conversion of high mannose type oligosaccharide to the hybrid or complex type. The full length of the rat GnT-I gene was expressed in the filamentous fungus Aspergillus oryzae. A microsomal preparation from a recombinant fungus (strain NG) showed GnT-I activity that transferred N-acetylglucosamine residue to acceptor heptaose, Man(5)GlcNAc(2). The N-linked sugar chain of alpha-amylase secreted by the strain showed a peak of novel retention on high performance liquid chromatography that was same as a reaction product of in vitro GnT-1 assay. The peak of oligosaccharide disappeared on HPLC after beta-N-acetylglucosaminidase treatment. Mass analysis supported the presence of GlcNAcMan(5)GlcNAc(2) as a sugar chain of alpha-amylase from strain NG. Chimera of GnT-I with green fluorescent protein (GFP) showed a dotted pattern of fluorescence in the mycelia, suggesting localization at Golgi vesicles. We concluded that GnT-1 was functionally expressed in A. oryzae cells and that N-acetylglucosamine residue was transferred to N-glycan of alpha-amylase in vivo. A. oryzae is expected to be a potential host for the production of glycoprotein with a genetically altered sugar chain.