Methyl hydroxypropyl cellulose

It may be possible to use less microbiologically susceptible raw materials. For example, hydroxypropyl methyl cellulose has been shown to be more resistant than hydroxyethyl and carboxymethyl cellulose (Briggs, 1980). 

Proteins or antibodies (36 pg) were mixed with ampholine pH 3.5—9.5 (final concentration of 5%, Amersham Biosciences, distributed by GE Healthcare, Uppsala, Sweden), p7 markers (Bio-Rad, Hercules, CA), and hydroxypropyl methyl cellulose (final concentration of 0.2% HPMC, Sigma-Aldrich, St. Louis, MO). The final protein concentration was 0.3mg/mL. Figure 17 shows a schematic of the sample preparation. The mixture was mixed thoroughly and was introduced to the capillary (eCAP neutral-coated, 50 micron X 30 cm, Beckman, Fullerton, CA) by hydrodynamic injection. Injections were performed using 20 psi for 99 s. The solution was then separated under an electric field of 25 kV for 10 min. The focused protein was then pushed/pulled out of the capillary through a mobilization process using the cathodic mobilizer (Bio-Rad, Hercules, CA). 

Add and mix in step 5 hydroxypropyl methyl cellulose and simethicone emulsion. 

Gustafsson, C. Nystrom, C. Lennholm, H. etal., Characteristics of hydroxypropyl methyl-cellulose influencing compactability and prediction of particle and tablet properties by infrared spectroscopy J. Pharm. Sci. 2003, 92, 460-470. 

Polymers such as polyfvinyl alcohol), dextrans, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, and polyfethylene oxide) can be used as dynamic or permanent coatings. The latter mode is generally more effective. 

Hydroxypropyl methyl cellulose [24] 10-80 12 Hypromellose, HPMC, MHPC... 

Tahara, K., Yamamoto, K., and Nishihata,T. (1996), Application of model-independent and model analysis for the investigation of effect of drug solubility on its release rate from hydroxypropyl methyl cellulose sustained-release tablets, Int. J. Pharm., 133, 17-27. 

Ford, J. L., Rubinstein, M. H., and Hogan, J. E. (1985), Propranolol hydrochloride and aminophylline release from matrix tablets containing hydroxypropyl methyl cellulose, Int. /. Pharm., 24,339-350. 

Velasco, M. V., and Ford, J. L., Rowe, R, and Rajabi-Siahhoomi, A. R. (1999), Influence of drug Hydroxypropyl methyl cellulose ratio, drug and polymer particle size and compression force on the release of diclofenac sodium from HPMC tablets, J. Controlled Release, 57, 75-85. 

Sheskey, P. J., Cabelka, T. D., Robb, R. T., and Boyce, B. M. (1994), Use of roller compaction in the preparation of controhed-release hydrophilic matrix tablets containing methyl cellulose and hydroxypropyl methyl cellulose polymers, Pharm. Technol., 18,132, 134,136,138,140,142,144,146,148-150. 

Dahl,T. C., Calderwood,T., Bormeth, A.,Trimble, K., and Piepmeier, E. (1990), Influence of physicochemical properties of hydroxypropyl methyl cellulose on naproxen release from sustained release matrix tablets, J. Controlled Release, 14,1-10. 

Shah, N. H., Railkar, A. S., Phuapradit, W., Zeng, F. W., Chen, A., Infeld, M. H., and Malick, A. W. (1996), Effect of processing techniques in controlling the release rate and mechanical strength of hydroxypropyl methyl cellulose based hydrogel matrixes, Eur. J. Pharm. Biopharm., 42,183-187. 

Talukdar, M. M., Michoel, A., Rombaut, P., and Kinget, R. (1996), Comparative study on xanthan gum and hydroxypropyl methyl cellulose as matrixes for controlled-release drug delivery I. Compaction and in vitro drug release behavior, Int. J. Pharm., 129, 233-241. 

Like PVA, the viscosity enhancer hydroxypropyl methyl-cellulose is available in a variety of molecular weights and in formulations with different group substitutions. It has been shown to prolong tear film wetting time and to increase the ability of fluorescein and dexamethasone to penetrate the cornea. Hydroxypropyl methylcellulose 0.5% has been shown to exhibit twice the ocular retention time of 1.4% PVA. 

Fig. 13 Influence of compression pressure on the ( ) porosity and adhesion of film formulations containing ( ) low viscosity and ( ) high viscosity hydroxypropyl methyl-cellulose (A) porosity (%) (B) adhesion (kPa). (From Refills].)...

Fig. 14 The effect of lubricant concentration (% w/w) on the measured adhesion (kPa) of hydroxypropyl methyl-cellulose films (A) Pharmacoat 606 (B) Methocel 60HG viscosity 50 ( ) stearic acid ( ) magnesium stearate ( ) calcium stearate. (From Ref. l)...

Frohoff-Hulsmann, M.A. Schmitz, A. Lippold, B.C. Aqueous ethyl cellulose dispersions containing plasticizers of different water solubility and hydroxypropyl methyl-cellulose as coating material for diffusion pellets. I. Drug release rates from coated pellets. Int. J. Pharm. 1999, 177, 69-82. 

J.K. Effect of some excipients and compression pressure 140. on the adhesion of aqueous-based hydroxypropyl methyl-cellulose film coatings to tablet surface. Drug Dev. Ind. 

Weiss, G. Knoch, A. Laicher, A Stanislaus, F. Daniels, R. Simple coacervation of hydroxypropyl methyl cellulose phthalate (HPM(7P). I. Temperature and pH dependency of coacervate formation. Int. J. Pharm. 1995,124 (1), 87-96. 

In another study, Wu et al. from China used a neural network to model the formulation of salbutanol sulfate osmotic pump tablets, using the amount of hydroxypropyl methyl cellulose and polyethylene glycol present in the cellulose acetate coating, in addition to the coating weight, as control factors. Using the model, the authors predicted the release parameters for 1000 formulations, from which they selected an optimum with the desired release pattern. 

---