Influence of Substitution Pattern on Solution Behavior of Hydroxypropyl Methylcellulose
Journal article, 2009

Industrially produced hydroxypropyl Me cellulose (HPMC) is a chem. heterogeneous material, and it is thus difficult to predict parameters related to function on the basis of the polymer's av. chem. values. In this study, the soln. behavior of 7 HPMC batches was correlated to the mol. wt., degree of substitution, and substituent pattern. The initial onset of phase sepn., so-called clouding, generally followed an increased av. mol. wt. and degree of substitution. However, the slope of the clouding curve was affected by the substitution pattern, where the heterogeneously substituted batches had very shallow slopes. Further investigations showed that the appearance of a shallow slope of the clouding curve was a result of the formation of reversible polymer structures, formed as a result of the heterogeneous substituent pattern. These structures grew in size with temp. and concn. and resulted in an increase in the viscosity of the solns. at higher temps.

Cloud point

Phase separation

Viscosity (substitution pattern effect on soln. behavior of hydroxypropyl Me cellulose)

substitution soln behavior hydroxypropyl methyl cellulose

Molecular weight distribution


Anna Viridén

SuMo Biomaterials

Chalmers, Chemical and Biological Engineering, Pharmaceutical Technology

Bengt Wittgren

AstraZeneca AB

Thomas Andersson

AstraZeneca AB

Susanna Abrahmsén-Alami

AstraZeneca AB

Anette Larsson

Chalmers, Chemical and Biological Engineering, Pharmaceutical Technology

SuMo Biomaterials


1525-7797 (ISSN) 1526-4602 (eISSN)

Vol. 10 3 522-529

Subject Categories

Pharmaceutical Sciences



More information

Latest update