Peptide drugs oral administration with formulations

The nasal tissue is highly vascularized and provides efficient systemic absorption. Compared with oral or subcutaneous administration, nasal administration enhances bioavailability and improves safety and efficacy. Chitosan enhances the absorption of proteins and peptide drugs across nasal and intestinal epithelia. Gogev et al. demonstrated that the soluble formulation of glycol chitosan has potential usefulness as an intranasal adjuvant for recombinant viral vector vaccines in cattle [276]. 

Many drugs can now be delivered rectally instead of by parenteral injection (intravenous route) or oral administration. Generally, the rectal delivery route is particularly suitable for pediatric and elderly patients who experience difficulty ingesting medication or who are unconscious. However, rectal bioavailabilities tend to be lower than the corresponding values of oral administration. The nature of the drug formulation has been shown to be an essential determinant of the rectal absorption profiles. The development of novel absorption enhancers with potential efficacy without mucosal irritation (low toxicity) is very important. The delivery of peptide and protein drugs by the rectal route is currently being explored and seems to be feasible. 

Oral Administration of Peptide Drugs with Mucoadhesive Liposomal Formulations... 

It is well known, that the co-administration of poorly water soluble drugs with a meal rich in fat can enhance the oral bioavailability of poorly water soluble drugs and lipid based delivery systems mostly based on complex lipid mixtures are intensively studied to enhance the bioavailability of poorly water soluble drugs. ° ° A couple of lipid based formulations are already on the market, e.g. for cyclosporine (Neoral ), retonavir (Norvir ), saquinavir (Fortovase ) and amprenavir (Agenerase ). Formulations of solid lipid nanoparticles may present a further alternative for oral delivery of poorly water soluble drugs as well as for proteins and peptides with low oral bioavailability due to degradation in the intestinal fluids. ... 

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