Preparation of self-assembled microspheres and their potential for drug delivery

Abstract

Dextran solutions intended for use as plasma extenders have been observed to form insoluble precipitates. Earlier studies of precipitation have shown that in solutions of 50% and 60% w/w of dextran molecular mass 6000 g mol(-1) beaded precipitates are formed over a two-week period. This study considers dextran precipitation over a wider molecular mass range and the kinetics, of formation, morphology and potential utility of these precipitates is investigated. Results show precipitation occurs over the dextran molecular mass range 6000-17,000 g mol(-1), with lower molecular mass material showing more rapid precipitation. As bead formation is accompanied by an increase in turbidity, formation kinetics were quantified spectrophotometrically confirming that precipitation rates were inversely proportional to molecular mass. The utility of these precipitates for drug delivery applications was assessed using bovine serum albumin as a protein drug analogue. The results showed that the inclusion of protein did not prevent bead formation and that entrapped protein was subsequently released from dextran beads in a time dependant manner. This suggests that dextran beads of this type may find application in the drug delivery area, as they combine the advantages of mild entrapment conditions with the use of an unmodified clinically approved polymer.

Microbial Fabricated Nanosystems: Applications in Drug Delivery and Targeting

“…Dextrans and derivatives produced from Leuconostoc sp. growing on sucrose, Streptococcus, Lactobacillus, and Gluconobacter sp have been used in controlled release system in nasal and colon targeting (Mellors et al, 2010;. Xanthan is another anionic and a naturally acetylated cellulose derivative from Xanthomonas campestris.…”

Supramolecular Complexation of Carbohydrates for the Bioavailability Enhancement of Poorly Soluble Drugs

“…Depending on the polysaccharide species or molecular weight, the average particle sizes are varied by changing the solution viscosity [186]. The preparation methods for microsphere using polysaccharides are solvent extraction [187], spray-drying [188], emulsion-crosslinking [166,179,189] and precipitation [190]. The conventional preparation methods have also been modified for property improvement.…”

Preparation and Characterization of a Novel Morphosis of Dextran and Its Derivatization with Polyethyleneimine

“…Hydrophobically modified dextrans with surface-active characteristics have been employed as effective emulsion stabilizers, replacing conventional emulsifiers [10]. Additionally, self-assembled microspheres formed from insoluble precipitates in dextran solutions have shown the ability to encapsulate and subsequently release proteins, indicating promising prospects as drug carriers [11]. Furthermore, the utilization of dextran hydrogels as drug carriers for sustained and controlled release was facilitated through the physical cross-linking of aqueous dextran solutions [9].…”