Magnesium Aluminometasilicate Research Articles

Nanoporous Magnesium Aluminometasilicate Tablets for Precise, Controlled, and Continuous Dosing of Chemical Reagents and Catalysts: Applications in Parallel Solution-Phase Synthesis

Mechanically robust tablets of nanoporous magnesium aluminometasilicate with high surface area and porosity can be loaded with a variety of organic and inorganic reagents and catalysts. The scope of this novel dosing methodology is demonstrated through the evaluation of 14 diverse organic reactions, including Mitsunobu, Suzuki, and bromination reactions.

Effect of adsorbents on the absorption of lansoprazole with surfactant

Lansoprazole (LPZ) is a representative drug that shows a high inter-subject variation of bioavailability (BA). Solid preparation composed of surfactant, adsorbent and LPZ were prepared to improve the dissolution and absorption of LPZ, and the BA of LPZ was measured in rats and dogs. As surfactant, Tween 80, polyoxy 60 hydrogenated caster oil derivative (HCO-60) and PEG-8 caprylic/capric glycerides (Labrasol) were used. As adsorbant, porous silicon dioxide (Sylysia 550, 320), magnesium aluminometa silicate (Neusilin S 2, NS 2N, US 2,) and porous calcium silicate (Florite RE) were used. After small intestinal administration of LPZ, 5.0 mg/kg, solution with HCO-60 showed the highest plasma LPZ concentration versus time curve of which C max and AUC was 0.46 ± 0.01 μg/mL and 0.73 ± 0.03 μg h/mL. By comparing to that after i.v. injection of LPZ solution, 2.0 mg/kg, the BA of LPZ from HCO-60 solution was 39.0%, which was about seven times higher than that of LPZ powder. To solidify the LPZ solution with HCO-60, adsorbents were used and the obtained solid preparations were used for in vitro release experiment. Sylysia 320, Neusilin S 2 and Neusilin NS 2 showed the T50% of about 1 h. To evaluate the BA of these solid preparations, absorption study was performed in rats. Sylysia 550 system showed the higher AUC than other systems, showing the BA of 28.1%. Sylysia 550 system was filled in an enteric capsule and was orally administered to dogs and BA was compared with enteric tablet. The AUC of Sylysia 550 system was 2.16 ± 0.26 μg h/mL and was greater than enteric tablet and the BA of 71.7% was obtained. Solid system composed of LPZ, surfactant and adsorbent has suggested the possibility as a good tool to improve the BA of LPZ.

Process characteristics and compaction of spray-dried emulsions containing a drug dissolved in lipid

The objective of the present study is to prepare directly compressible powders, containing a poorly water-soluble drug dissolved in medium-chain triglycerides (MCT), by spray drying o/w-emulsions in a pilot plant spray dryer. In addition to the lipid phase, the emulsions contained a water-soluble carrier (a sugar), a water-insoluble carrier (magnesium alumino metasilicate) and a combined emulsifier and film-forming agent (gelatine). A factorial design was used to investigate the effect of formulation variables on the spray drying process and powder properties. The factors varied were soluble carrier type (trehalose or mannitol), insoluble carrier particle size distribution (granular or fine powder) and amount of lipid phase in the emulsion (low or high). Compressibility and compactibility of the spray-dried emulsions were mainly affected by the content of lipid in the powders and decreased on increasing the amount of lipid. Increasing the particle size of the insoluble carrier decreased spray drying process yield and lipid encapsulation efficiency whereas compactibility and handling properties were improved. Incorporation of a soluble carrier becoming amorphous on spray drying resulted in tablets with an increased mechanical strength compared to powders containing a crystalline soluble carrier.

塩酸グアニジンの吸湿特性に及ぼす添加剤と包装材料の影響

Guanidine hydrochloride, which is known to be effective in the treatment of Lambert-Eaton myasthenic syndrome, is very hygroscopic. Therefore, the mixture of the drug and lactose dispensed at hospital pharmacies tends to easily liquefy even under ordinary storage conditions because of poor compatibility. In this study the physicochemical and chemical stabilities of commercially available guanidine salts, namely hydrochloride, nitrate, carbonate, and sulfate, were investigated at various relative humidity levels. The critical relative humidity of the hydrochloride salt was significantly lower than the others and it was also more hygroscopic than the other three salts, however, nitrate was found to be sufficiently stable regarding humidity. The powder maintained a good flowability after long storage periods. The optimal diluent was selected to use in powders consisting of guanidine hydrochloride in order to stabilize the physicochemical and chemical properties. No solidification or change in appearance were observed in the mixture of the drug and magnesium aluminometasilicate (Neusilin® US2) as diluent and moisture adsorbent. The flow property (angle of repose) of this mixture was also investigated.

Development and application of HIP technology : H.Zheng et al. (Central Iron and Steel Research Inst., Beijing, China.)

In this paper, we explore the use of Neusilin, an inorganic magnesium aluminometasilicate, to stabilize the amorphous form of an acidic drug Sulindac. Both cryomilling and ball milling of the drug with Neusilin were found to produce the amorphous phase. However, the ball‐milled (BM) material exhibited superior physical stability when compared with the cryomilled material at 40°C/75% relative humidity. 13C solid‐state nuclear magnetic resonance investigation of the BM material revealed an acid–base reaction between Sulindac and Neusilin. Optimal milling conditions and the kinetics of salt formation were also established. As benchtop milling is a laboratory‐scale process, a scalable process was developed to make Sulindac–Neusilin amorphous drug complex using hot‐melt extrusion (HME). The dissolution properties of the resulting HME material was found to have been improved over the material made by benchtop milling while maintaining similar physical stability. The HME material was used to make tablets using a direct compression method. The HME tablets were found to have better dissolution properties than tablets made from crystalline Sulindac. For the broad class of acidic drugs containing the carboxyl moiety, inorganic silicates such as Neusilin would offer a better choice than organic polymers to stabilize the amorphous phase. © 2011 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:3332–3344, 2011