3.2.1.2 Modified celluloses

In the construction industry

Hydroxypropyl methyl cellulose, commonly abbreviated as HPMC, is a versatile pharmaceutical excipient widely used in the formulation of various dosage forms. This semi-synthetic polymer is derived from naturally occurring cellulose, which is modified through the addition of methoxy and hydroxypropyl groups to improve its solubility and stability in water. The resulting compound possesses unique characteristics that make it an indispensable component in the manufacturing process of tablets, capsules, films, and even some types of suspensions and emulsions. One of the primary functions of HPMC is as a binder in the production of tablets. It provides cohesion between particles, ensuring that the tablet maintains its structure during compression and post-production handling. Moreover, HPMC can act as a release-controlling agent due to its ability to form a gel layer upon contact with aqueous fluids. This property allows for the sustained or controlled release of active pharmaceutical ingredients (APIs), which can optimize therapeutic efficacy by maintaining drug levels within the desired therapeutic window over an extended period. In addition to its role in solid dosage forms, HPMC also finds application in the preparation of film coatings. These coatings protect the core tablet or capsule from environmental factors such as moisture and light while improving the aesthetic appeal and patient acceptability of the medication. Furthermore, the use of HPMC in film coatings can facilitate the development of modified-release dosage forms, where the rate at which the API is released into the body is carefully managed to suit the treatment regimen. Another notable advantage of using HPMC is its non-toxicity and biocompatibility Another notable advantage of using HPMC is its non-toxicity and biocompatibility

Substitution of cellulose with ethyl-, methyl-, hydroxypropyl-, hydroxypropyl-methyl- and carboxymethyl groups may increase the resistance of cellulose to degradation. Resistance increases with the degree of substitution and is greatest when the substituent groups are evenly dispersed along the polymer chain. Most cellulose of the additive under assessment will therefore pass the intestine undigested and will excreted unchanged via faeces. Even when a high cellulolytic activity is present, as in the rumen, ethyl cellulose remains sufficiently resistant to degradation to be used as enteric coatings designed to protect methionine from rumen release (EFSA FEEDAP Panel, 2012c). Subsequent degradation in the post-ruminal tract is most likely to lead to high molecule weight breakdown products, with little probability of absorption.

The present assessment is based on data submitted by the applicant in the form of a technical dossier5 in support of the authorisation request for the use of HPMC as a feed additive.

5. Medical devices:

Overall, the data set for genotoxicity is not complete for all the substances and several studies were not in line with the current standard. However, it should be considered that the chemical structure of unmodified and modified cellulose does not show any alert for genotoxicity and that no indication of genotoxicity was found for any of these substances in several in vitro and in vivo genotoxicity studies.