BIODEGRADABLE POLYMERS COMPOSED OF NATURALLY OCCURRING AMINO ACIDS
Fig. 1. AABBP solution in etha-nol & spray wound dressing Coladerm®
Fig. 2. Viscose-flow AABBP
Fig. 3. Wound dressing PhagoBioDerm® (Art. skin)
Fig. 4. Bone-like hard AABBP
Fig. 5. Microspheres and nanoparticles made of AABBPs
Fig. 6. Electrospun nanofibers and microporous films made of AABBPs
Fig. 7. Drug eluting vascular stent and drainage tube coated by AABBPs
High-molecular-weight Amino Acid Based Biodegradable Polymers (AABBPs) were synthesized using naturally occurring a-amino acids as main building blocks and fatty diols, dicarboxylic acids, α-hydroxy acids and carbonic acid as co-building blocks. Various classes of AABBPs were obtained. Those are poly(ester amide)s, poly(ester urethane)s, poly(ester urea)s and poly(depsipeptide)s. Both non-functional (regular) and functional AABBPs suitable for subsequent chemical and photochemical modifications were obtained using polyfunctional α-AAs and other functional/ unsaturated co-building blocks [1,2].
Innovative Aspects and Main Advantages
All the AABBPs obtained contain H-bond forming chemical units in the backbones that enhances their mechanical properties, hydrophilicity and tissue compatibility. The AABBPs obtained exhibit some obvious advantages over existing and commercially successful biodegradable polyesters like polyglycolic and polylactic acids, their co-polymers, poly(p-dioxanone), poly(caprolactone), etc. [1,2].
Areas of application
The selection of appropriate monomeric forms of a-AAs and other co-building blocks under optimal polycondensation methods allowed the synthesis of AABBPs with tailored material properties – soluble in ethanol – an organic solvent approved by FDA (Fig. 1)), viscose-flow (Fig. 2), high-elastic (Fig. 3) and hard (bone-like) materials (Fig. 4). The AABBPs are promising for numerous biomedical applications – from resorbable surgical devices (e.g. medicated artificial skin PhagoBioDerm® containing bacterioiphages, antibiotics, pain killer and enzymes, Fig. 3) to drug controlled/sustained eluting and target delivering systems like micro and nanoparticles (Fig. 5), electrospun nanofibers and microporous films suitable as scaffolds for cell cloning (Fig. 6), etc. [1,2]. Ethanol solutions of AABBPs (with or without medications) are suitable as spray wound dressings as well as to coat vascular stents and drainage tubes (Fig.7), catheters, etc.
Stage of development
Spray wound dressing Coladerm®, spray dressing with antimycotic properties Mycoderm®, and wound dressing PhagoBioDerm® are commercially available in Georgia . AABBP-coated drainage tubes are under clinical trials in Georgia. Functional AABBPs  and blends of AABBPs  we have developed, are being clinically examined as medicated (drug eluting) coatings for vascular stents as well as for other drug delivery devices by US companies MediVas (that pioneered the research focused on wide practical applications of AABBPs), SurModics, Guidant/Boston Scientific Corporation, Medtronic, Pfizer, Abbott and by DSM Biomedicals.
 R. Katsarava, Z. Gomurashvili, Biodegradable Polymers Composed of Naturally Occurring α-Amino Acids, Handbook of Biodegradable Polymers - Isolation, Synthesis, Characterization and Applications, Lendlein, A. and Sisson, A., Eds., Wiley-VCH, 107-131 (2011).
 R. Katsarava, D. Tugushi, Non-conventional polymers composed of naturally occurring a-amino acids, Journal of Characterization and Development of Novel Materials, 2(3-4), 325-342 (2011).
 C.C. Chu, R. Katsarava, U.S. Patents: 6,503,538; 7,304,122; 7,408,018 (2003, 2007, 2008).
 R. Katsarava, Z, Alavidze, U.S. Patent: 6,703,040 (2004).
Contact person: Prof. Ramaz Katsarava
Institute of Medical Polymeric Materials,
Iv. Javakhishvili Tbilisi State University,
1 Chavchavadze ave., 0179 Tbilisi, Georgia
Center for Medical Biotechnology & Bioengineering,
Georgian Technical University,
77 Kostava Street, Tbilisi, 0175, Georgia
Tel./Fax: +99532 2337594, +99532 2300194.