Evaluating the role of amino acids and isothermal dry particle coating in modulating buccal permeation of large molecule drug vancomycin.

The formulation and delivery of macromolecules through the oral route pose considerable challenges due to factors such as large molecular weight, pH sensitivity, and limited formulation approaches. This challenge is compounded if the drug is poorly permeable, necessitating innovative drug delivery strategies. Vancomycin, a widely prescribed glycopeptide antibiotic, has an oral bioavailability of less than 10%, leading to predominantly intravenous administration and potential patient discomfort. This study explores the potential of the buccal route as a non-invasive, highly vascularised alternative route of administration, offering a rapid onset of action while bypassing the first-pass metabolism. In this study, vancomycin was coated with L-glutamic acid using an isothermal dry particle coater to modulate permeation through the buccal cell line, TR146. Results confirm significant impact of both amino acid concentration and dry particle coating on the rate and extent of drug permeability. With the introduction of L-glutamic acid and utilisation of the isothermal dry particle coater, vancomycin's permeation profile increased six-fold compared to the control due to the formation of drug ion-pair complex. Imaging studies showed the presence of layered micronized glutamic acid particles on the surface of dry coated vancomycin particles which confirms the role of dry coating and amino acid concentration in modulating drug permeation. Microbiology experiments in Staphylococcus aureus, minimum inhibitory concentration and biofilm disruption studies, provided confirmatory evidence of antimicrobial activity of dry coated glutamic acid-vancomycin ion pair particulate structure. This study demonstrates, for the first-time, buccal delivery of dry coated large molecule drug, vancomycin, through controlled deposition of amino acid using innovative particle coating strategy.