Modeling of drug release from delivery systems based on hydroxypropyl methylcellulose (HPMC

Modeling of drug release from delivery systems based on
hydroxypropyl methylcellulose (HPMC )

Received 20 October 2000; received in revised form 7 December 2000; accepted 15 December 2000
The objective of this article is to review the spectrum of mathematical models that have been developed to describe drug
release from hydroxypropyl methylcellulose (HPMC)-based pharmaceutical devices. The major advantages of these models
are: (i) the elucidation of the underlying mass transport mechanisms; and (ii) the possibility to predict the effect of the
device design parameters (e.g., shape, size and composition of HPMC-based matrix tablets) on the resulting drug release rate,
thus facilitating the development of new pharmaceutical products. Simple empirical or semi-empirical models such as the
classical Higuchi equation and the so-called power law, as well as more complex mechanistic theories that consider
diffusion, swelling and dissolution processes simultaneously are presented, and their advantages and limitations are
discussed. Various examples of practical applications to experimental drug release data are given. The choice of the
appropriate mathematical model when developing new pharmaceutical products or elucidating drug release mechanisms
strongly depends on the desired or required predictive ability and accuracy of the model. In many cases, the use of a simple
empirical or semi-empirical model is fully sufficient. However, when reliable, detailed information are required, more
complex, mechanistic theories must be applied. The present article is a comprehensive review of the current state of the art
of mathematical modeling drug release from HPMC-based delivery systems and discusses the crucial points of the most
important theories

Modeling of drug release from delivery systems based on
hydroxypropyl methylcellulose HPMC.

Hydroxypropyl Methylcellulose

Polymer partially derived from cellulose. Used in bath products, hair shampoos, and skin cleansers. Is both soluble and insoluble depending on temperature exposure making this ingredient highly versatile.

Hydroxypropyl MethylcelluloseHydroxypropyl Methylcellulose (HPMC), also known as Hypromellose, is semi-synthetic polymer partially derived from cellulose. The polymers are created in response to a chemical reaction between cellulose and ethylene or propylene oxides or it can be developed between cellulose and both of these substances.

It is ommonly used in bath products, hair shampoos, and skin cleansers and is effective as a thickening agent to create gels and serums or as a binding agent. This component can be either soluble or insoluble in water depending on the temperature it is exposed to. When HPMC is exposed to hot water it becomes insoluble, where typically solubility is induced by heat exposure. This makes it excellent additive to lotions and creams. It also helps to produce a silkiness to these products. When exposed to cold temperatures it becomes soluble forming a gel. This consistency is useful in shower gels, shaving gels, and serums. It also capable of producing crystal clear solutions and forms a film upon drying which acts as a protective barrier for the skin.