Quantification of the bioadhesive properties of protein-coated PVM/MA nanoparticles

This work describes the bioadhesive properties of poly(methyl vinyl ether-co-maleic anhydride) (PVM/MA) nanoparticles fluorescently-labelled with rhodamine B isothiocyanate, and coated with either Sambucus nigra lectin (SNA-NP) or bovine serum albumin (BSA-NP). The different formulations (10 mg) were administered to animals by the oral route and the fraction of adhered particles to the mucosa was estimated by measuring the fluorescent marker after the digestion of the tissue. Plotting the amount of adhered particles in the whole gut versus time enabled us to determine the affinity of the formulation for the biological support (expressed as Q(max)), the intensity and relative duration of the bioadhesive phenomenon (AUC(adh) and MRT(adh), respectively), and the elimination rate of the adhered particles (k(adh)). SNA-NP displayed a similar adhesive affinity and adhesive intensity for the gut mucosa than the control particles; although, its maximum of interaction with the mucosa was observed 1 h post-administration, whereas control and BSA-NP took place only 30 min post-administration. On the other hand, the coating of nanoparticles with SNA significantly reduced the k(adh) (P<0.01) and, thus, MRT(adh) was 35 min longer for the lectin-conjugate than for the control. BSA-NP displayed a highest initial affinity for the gut mucosa and AUC(adh) was calculated to be 1.5 fold higher than for the control or SNA-NP. However, BSA-NP were eliminated more rapidly from the mucosa than SNA-NP and, thus, the MRT(adh) was only 27 min longer than control. In summary, the parameters describing the bioadhesive profile of a given formulation may be useful to quantify the potential of colloidal particulates to interact with a mucosa and to evaluate the influence of different ligands on the bioadhesive properties of the resulting drug carriers.