Tablet Dissolution

Dissolution problems with film-coated tablets occur when there is a statistically significant change in dissolution behavior after film coating (comparing film-coated tablets to uncoated ones). Although a number of factors may be involved here, the most prominent one is the impact of coating process conditions on tablet core behavior, rather than the impact of the applied coating itself.

Tablet Core

Some tablet core formulations are sensitive to film-coating processing conditions (typically heat and moisture, although mechanical stress can also be a factor). A classic example occurs with ibuprofen tablets, where the relatively low melting point of this API makes it very susceptible to heat in the coating process, especially aqueous processes where higher processing temperatures are used compared to those with organic solvent–based coating formulations. Learn more

  • Adjust the core formulation to improve dissolution behavior and offset sensitivity to processing conditions.

Coating Formulation

Although interactions between ingredients in the coating formulation and those in the tablet core (primarily with the API) can impact dissolution, most interactions result in chemical stability problems (such as between peroxides in the coating and the API) rather than dissolution problems. Nonetheless, there are occasions when the type of coating formulation used might have some negative impact on tablet dissolution behavior. Learn more

  • Adjust the coating formulation to allow the coating process temperatures to be reduced (see Coating Process section for further discussion).

Coating Process

Unacceptable changes in tablet dissolution behavior after film coating result from exposure of tablet cores to coating process conditions. Penetration of moisture into the cores during application of an aqueous film coating can cause partial inactivation of disintegrants, with concomitant impact on dissolution. In addition, exposure to heat can cause dehydration of the tablet cores, and potentially melting of low melting point APIs (such as ibuprofen), with the result that drug dissolution behavior is changed.

  • High solids film-coating systems, such as Aquarius Preferred HSP, can facilitate the use of much gentler process conditions and, thus, obviate the impact of high temperature processing conditions on tablet dissolution behavior. Learn more