The use of nano-structured hybrid materials for oral drug delivery

We have used a novel hybrid nano-structured sponge to conduct proof of concept studies for the oral delivery of peptides employing insulin as the loaded model drug. The hybrid sponge was synthesized from a modified acid-base neutralization reaction for hydroxyapatitc (HA) incorporating cMtosan (CHT) as the organic counterpart. The trace addition of chitosan during synthesis resulted in a hybrid colloidal suspension which could be dried to from this hybrid sponge. The sponge morphology was unique indicating two levels of structure with assembled nanoparticles combined with nanoporous HA-CHT architecture. These films showed relatively high levels of insulin loading (~700IU/g of carrier) and could be coated with an alginate based gel. Release of insulin in simulated gastric and intestinal fluids (SGF and SIF) indicated that release was predominant in intestinal conditions and that a complex double mode kinetic release profile was inherent in the system. However, we believe at this stage that this characteristic can be rationalized as the combined effect of release from the drug adsorbed onto the nanoparticles and condensed into the nanoporous architecture. Overall the loading and release were promising and further studies are currently underway to incorporate other functional modifications in the sponge and in vitro characterization.