Hydroxypropylmethylcellulose, excipient

This product contains no less than 19% and no more than 30% methoxy groups and no less than 3 % and no more than 12 % hydroxypropyl residues. It occurs as a white fibrous granular powder. Hydroxypropylmethylcellulose is employed as a suspending or a thickening agent and tablet excipient. Solutions of this hydrophilic polymer are used as topical protectants or as artificial tears for contact lenses. 

Hypromellose or hydroxypropylmethylcellulose (HPMC) is a semisynthetic, inert, viscoelastic polymer, which is used as an ophthalmic lubricant, an excipient and controlled delivery component in oral medicaments and is found in a variety of commercial products [111]. Hypromellose is used as an alternative to animal gelatin and as an emulsifier, thickener, and suspending agent. 

Figure 4 shows the of lyophilized formulations containing various polymer excipients as a function of relative humidity [26], As relative hymidity increased, for each formulation decreased. Formulations containing a, S-poly (vV-hydroxyethyl)-L-aspartamide (PHEA), methylcellu-lose (MC), and hydroxypropylmethylcellulose (HPMC) exhibited comparable r io values at lower humidities than formulations with dextran and carboxymethylcellulose sodium salt (CMC-Na). This indieates that the formulations containing PHEA, MC, and HPMC contain highly mobile protons at a lower temperature than the formulations containing dextran and CMC-Na at the same humidity. 

Z. Lu, W. Chen, E. Olivier, J.H. Hamman, Matrix polymeric excipients Comparing a novel interpolyelectrolyte complex with hydroxypropylmethylcellulose. Drug Deliv, 15 (2),... 

L.C. Feely, S.S. Davis, The influence of polymeric excipients on drug release from hydroxypropylmethylcellulose matrices. /Pharm, 44 131-139,1988. 

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