[Effect of Methylcellulose (Cellulose Derivatives) on Ibuprofen-crushing Efficiency in Nano Pulverizer NP-100]

It is expected that drug systems using nanoparticles will improve the problem of poor water solubility and bioavailability of lipophilic drugs. However, it is difficult to prepare the formulations containing nanoparticles, and it is important to determine the concentration and kind of additives to prepare the formulations. We previously reported that a nano pulverizer NP-100 is possible to prepare drug nanoparticles for the 2-3 min, and the cellulose derivatives (metolose^®, methylcellulose) is usefulness to prepare the nanoparticles by the mill method. In this study, we investigated the relationships of methylcellulose type and crushing efficiency in NP-100. First, we demonstrated the effect of viscosity in the various methylcellulose on the ibuprofen (IBU, lipophilic drug) particle size, and showed that the viscosity did not relate the crushing efficiency by the NP-100. Next, we measured the changes of cumulative size frequency curve in IBU particles by the combination of the NP-100 and 0.1-2.0% methylcellulose (SM-4, 400 and 4000). The appropriate addition reached IBU nanoparticles, although, the appropriate addition amount of methylcellulose was different in the SM-4 (0.5%), 400 (1.0%) and 4000 (1.2%). In addition, the IBU became meringue-like when subjected to the bead mill method in the less of methylcellulose, and excessive addition of methylcellulose increased the ratio of coarse particle. In conclusion, this results show that the appropriate addition amount of methylcellulose is different in the type of methylcellulose, and these changes of cumulative size frequency curve is useful as index to determine the concentration and type of additives in the nanoparticle production.