The Effect of Adsorbed Water on Compaction Properties and the Dissolution of Quinacrine Hydrochloride from Compacted Matrices of Soy Protein

Abstract

Albuminoid proteins are a byproduct of soya bean processing and are widely employed as inexpensive food additives. Native (undenatured) commercial soy protein has been evaluated in this preliminary study as a tablet excipient since it is readily compressed and has considerable potential as a non-toxic tablet matrix. In addition, it provides an inexpensive model of albuminoid proteins obtained from other natural sources such as serum of various species.

Gravimetric measurement of water adsorption demonstrated the capacity of soy protein to equilibrate at various water concentrations when exposed to different relative humidities over a range of 15–80% R. H.

Mixtures (1:4) of Quinacrine dihydrochloride and soy protein powders were exposed to various relative humidities and compressed into matrices under standardized conditions over a range of pressures from 60 to 230 MPa.

The protein compacts were directly affected by the initial water level of the powder, being stronger and more readily compressed with increased water adsorption. Although low water levels, < 51% RH, resulted in relatively loosely compacted matrices, surprisingly the drug release rates into water at 37°C were somewhat slower. This unexpected result may be attributed to changes produced in the pore structure of the compacts by the soy protein welling under these conditions.