Hydrophobic agave fructans for sustained drug delivery to the human colon

Abstract

Given their glycosidic β 2−1 and β 2−6 linkages, fructans from Agave tequilana Weber var. azul (AtF) may be employed for the design of drug carriers targeting the human colon. However, the high water solubility of AtF prevents their use for such a purpose. In this work, AtF were esterified with acetyl, lauroyl and palmitoyl groups with the aim to encapsulate ibuprofen as a model drug and characterize its enzymatic release in simulated colon conditions. It was found that efficiency of encapsulation increased from 0.8% (unmodified fructan) to 17 or 21.5% when AtF was esterified with acetyl groups at high degree of substitution (2.75 DS) or with a long acyl chain such as palmitoyl at low DS (0.18) respectively. Hydrophilic fructan based microspheres (AtF, and lauroyl fructan, 46 and 61.3° contact angle respectively) had poor encapsulation efficiency (0.8–1.5%) and lost most of their cargo (85%) at gastric conditions. In contrast, hydrophobic fructan based microspheres (acetyl and palmytoyl, 91–98° contact angle) showed high stability at gastric pH and were able to release the drug for long periods. These characteristics make hydrophobic fructans appropriate vehicles that show great potential for the delivery of drugs to the colon, allowing long drug bioavailability during its delivery and release.