Hydrogels for Specific Applications

Hydrotropic Hydrogels for Delivery of Poorly Soluble Drugs 

Drug molecules have to be dissolved in the GI tract to be absorbed. Poor aqueous solubility of hydrophobic drugs, which usually results in low bioavailability, has been one of 

Inununization has been relied on in the induction of humoral inununity by parenteral administration of vaccines. Antibodies from this do not necessarily reach the mucosal surfaces of the GI tract where most infectious agents encoxmter the host first. Secretory IgA (sIgA) is the dominant antibody isotype present at mucosal sites. Since sIgA inhibits the attachment of bacteria and viruses to mucosa and neutralizes toxins, mucosal immunity can provide the first line of immunological defense. However, induction of immunity at mucosal surfaces needs administration of vaccines directly to the mucosal site. 

Since vaccines are quite susceptible to low pH in the stomach and enzymatic degradation in the GI tract, various methods have been tried to improve the vaccine delivery. Alginate microspheres have been examined to deliver vaccines by oral administration (38). Vaccine-containing 

Kamath KR, Park K. Biodegradable hydrogels in drug delivery. Adv Drug Delivery Rev 1993 11 59-84. 

---