The release of lactose (hydrophilic) from polymer tablets made with hydrophobically modified poly
(acrylic acid) (HMPAA) have been studied and compared to the release of ibuprofen, a hydrophobic active
substance. Lactose is one of the most used excipients for tablets, but lactose release has not been widely
studied. One reason could be a lack of good analytical tools. A novel biosensor with cellobiose
dehydrogenase (CDH) was used to detect the lactose release, which has a polydiallyldimethylammonium
chloride (PDADMAC) layer that increases the response. A sample treatment using polyethylenimine (PEI)
was developed to eliminate possible denaturants. The developed methodology provided a good approach
to detect and quantify the released lactose. The release was studied with or without the presence of a
model amphiphilic substance, sodium dodecyl sulphate (SDS), in the release medium. Ibuprofen showed
very different release rates in the different media, which was attributed to hydrophobic interactions
between the drug, the HMPAA and the SDS in the release medium. The release of hydrophilic lactose,
which did not associate to any of the other components, was rapid and showed only minor differences.
The new methodology provides a useful toolto further evaluate tablet formulations by a relatively simple
set of experiments.