Payer’s patches

Membranous epithelial cells (Fig. 3), M-cells or microfold cells, ate local ized in regions overlying lymphoid follicles, which are known as Payer s patches... 

Uptake of intact nanoparticulates from the gastrointestinal tract (GIT) after oral administration, for example, by endocytosis by the M cells of Payer s patches, is an area of controversy. Most research shows that the efficiency of this process is extremely low (much less than 1%), the extent is poorly defined and subject to great variability. Rather, it is the enhanced rate of dissolution of nanoparticulates which results in improved exposure. ... 

The autopsy findings are very characteristic. They consist in swelling and reddening of Payer s Patches and mesenteric lymph glands, internal hemorrhages and diffuse nephritis. Cruz, Flexner, Mueller and others have shown that these lesions are not due to thrombosis, but to direct action on the tissues. The site of the injection is boggy. 

Shakweh, M. et al. Particle uptake by Payer s patches A pathway for drug and vaccine delivery. Expert Opin. Drug Deliv., 1, 141, 2004. 

Lubben, l.M.V. et al. Chitosan microparticles for oral vaccination Preparation characterization and preliminary in vivo uptake studies in mnrine payer s patches. Biomaterials, 22, 687, 2001. 

Borges, O., SUva, A. C., Romeijn, S. G., Amidi, M., de Sousa, A., Borchard, G., and Junginger, H. E. 2006. Uptake studies rat Payer s patches, cytotoxicity and release studies of alginated coated chitosan nanoparticles for mucosal vaccination. J. Control. Release 114 348-358. 

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