HPMC hydroxypropyl methylcellulose

ECL = endothelial cell line, HY = hyaluronate-based viscoelastic substance, HPMC = hydroxypropyl-methylcellulose, V = Viscoat (4% chondroitin sulfate and 3% hyaluronate), > = more than, ns = not statistically significant... 

Iyer et al. [50] investigated the effects of roto-granulation on the performance of hydroxypropyl methylcellulose (HPMC), gelatin, and poly(-vinylpyrrolidone) (Povidone, PVP). In this process, all three binders produced similar results. However, HPMC was preferred due to prolonged drug release profiles, smaller particle size, and better content uniformity. 

Starches Hydroxypropyl methylcellulose (HPMC) Polyvinyl alcohol (PVA)... 

Figure 2 illustrates the temperature dependence of the swelling degree as a function of precursor polymer type. Methylcellulose (MC), hydroxypropyl-methylcellulose, type E (HPMC-E) and hydroxypropylmethylcellulose, type K (HPMC-K) gels have comparable effective crosslink densities of about 2 x 10 5 mol/cm3 (as determined from uniaxial compression testing), while the crosslink density of the hydroxypropylcellulose (HPC) gel is about half this [52]. The transition temperature for each gel is within several degrees of the precursor polymer lower critical solution temperature (LCST), except for the MC gel, which has a transition temperature 9 °C higher than the LCST. The sharpness of the transition was about 3%/°C, except for the HPC gel transition, which was much sharper - about 8%/°C. 

A popular approach to improve ocular drag bioavailability is to incorporate soluble polymers into an aqueous solution to extend the drug residence time in the cul-de-sac. It is reasoned that the solution viscosity would be increased and hence solution drainage would be reduced. The more commonly used viscolyzing agents include PVA and derivatives of cellulose. Cellulosic polymers, such as methylcellulose, hydroxyethylcellulose (HEC), hydroxypropyl-methylcellulose (HPMC) and hydroxypropylcellulose (HPC), are widely used as viscolyzers showing Newtonian properties. They have common properties ... 

Siepmann, J. and Peppas, N., Modeling of drug release from delivery systems based on hydroxypropyl methylcellulose (HPMC), Advanced Drug Delivery Reviews, Vol. 48, No. 2-3, 2001, pp. 139-157. 

Cellulose derivatives Chitosans Gelatin Sodium carboxymethylcellulose (NaCMC) Methylcellulose (MC) Hydroxypropyl methylcellulose (HPMC) Hydroxypropyl cellulose (HPC) Hydroxyethyl cellulose (HEC)... 

Hydroxypropyl methylcellulose (HPMC) 2-8 Low-viscosity grades most widely used... 

Substituted Cellulose Ethers. Since their introduction for ophthalmic use, MC and other substituted cellulose ethers such as hydroxyethylcellulose, hydroxypropylcel-lulose, hydroxypropyl methylcellulose (HPMC), and carboxymethylcellulose (CMC) have been used in artificial tear formulations.These colloids dissolve in water to produce colorless solutions of varying viscosity. They have the proper optical clarity, a refractive index similar to the cornea, and are nearly inert chemically. Their relative lack of toxicity, their viscous properties, and their beneficial effects on tear film stability have made cellulose ethers useful components of artificial tear preparations. Historically, the most frequently used representative of this group was MC. 

Hydroxypropyl methylcellulose (HPMC) Methylated HPC Similar to HPC Substituted pyranose chain sequences... 

Hydroxypropyl Methylcellulose (HPMC) Suzuki and Sunada. report the production of solid dispersions prepared with nicotinamide and HPMC as combined carriers using nifedipine and nitrendipine as model drugs. Their solid dispersions were obtained using the fusion method. After both the drug and HPMC were dissolved in the liquid melt of nicotinamide at 140°C, the fused mixture was cooled to solidify it. 

Hydroxypropyl methylcellulose (HPMC) is produced similarly to hydroxypropyl cellulose except that methyl chloride is included in the reaction. The composition of the substituted hydroxyl groups ranges from 3% to 12% hydroxypropyl and from 19% to 30% methyl. HPMC is soluble in cold water and the polyethylene glycols up to 600 Da, but, in contrast to hydroxypropyl cellulose, HPMC is not soluble in alcohol. It is also less susceptible to hydrolysis, and is stable from pH 3 to 11. 

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