Alginate in drug delivery systems.

Area of Science:

• Polymer Science
• Materials Science
• Pharmaceutical Sciences

Background:

• Alginates are versatile biopolymers with established uses in drug products, primarily for thickening, gel-forming, and stabilizing.
• The demand for controlled drug administration necessitates tailor-made polymers, with hydrocolloids like alginate playing a key role.

Purpose of the Study:

• To review the current applications and future potential of alginate as a pharmaceutical excipient in drug formulation.
• To highlight alginate's unique properties for developing controlled-release drug delivery systems.

Main Methods:

• Discussion of alginate's chemical properties, including its ability to form acid gels at low pH and ionotropic gels with divalent cations.
• Review of alginate's physical characteristics, such as bead formation and diffusion barrier properties.
• Examination of the availability of various alginate grades and salts, including ultrapure forms for implants.

Main Results:

• Alginate forms two distinct types of gels (acid and ionotropic) due to pH-dependent hydration and cation interaction, offering unique properties.
• Alginate beads create diffusion barriers, effectively controlling the migration of small molecules like drugs.
• Over 200 alginate grades are available, with potential pharmaceutical applications yet to be fully explored.

Conclusions:

• Alginate's unique gelling properties and tailor-made potential position it as a significant contributor to advanced polymeric drug delivery systems.
• The polymer's adoption by Ph.Eur. and availability in ultrapure forms support its use in pharmaceutical formulations, including implants.