Study of the physical properties of kafirin during the fabrication of tablets for pharmaceutical applications

Kafirin and protein bodies were extracted from a condensed tannin-free white Sudanese cultivar of sorghum (Dabar). The extracted materials were characterized by SDS-PAGE. The potential of kafirin as a tablet matrix for pharmaceutical applications was studied. Tablets composed of kafirin, calcium hydrogen orthophosphate, caffeine and magnesium stearate were prepared by direct compression. The tablets showed appropriate levels of hardness and friability. Drug release studies showed that caffeine dissolution was greater in 0.1 M HCl than in either phosphate buffer (pH = 6.8) or distilled water. Deamidation of the protein in acid conditions might explain this observation. FTIR analysis showed that the secondary structure of kafirin was found to be mainly governed by α helices with some β sheets. Upon tabletting, there was a change in protein conformation, which was recovered upon dissolution irrespective of the dissolution media. This might be explained by the loss of protein coil to coil interaction during tabletting (possibly due to the diluting effect of calcium hydrogen orthophosphate). This was later recovered when tablets were dissolved due to the hydrophobic interactions between the kafirin proteins. In summary, this work has shown that kafirin has a potential for use as a tablet for drug delivery.