No abstract

Healing of poorly vascularized and venous stasis ulcers is often refractory to therapy, particularly when they are infected. Systemic antibiotic therapy may be of little benefit in this setting because of poor penetration of the antibiotic into the wound and the frequent associated emergence of bacterial strains resistant to common antimicrobial agents. Given the clinical significance of these problems, there is a need to explore alternative management approaches for these difficult-to-treat wounds. PhagoBioDerm is a novel wound-healing preparation consisting of a biodegradable polymer impregnated with an antibiotic and lytic bacteriophages, which was recently licensed for sale in the Republic of Georgia (one of the former Soviet Union republics). In 1999-2000, in Tbilisi, Georgia, 107 patients who had ulcers that had failed to respond to conventional therapy were treated with PhagoBioDerm alone or in combination with other interventions. The wounds/ulcers healed completely in 67 (70%) of 96 patients for whom follow-up data were available. In 22 cases in which microbiologic data were available, healing was associated with the concomitant elimination of, or a reduction in, specific pathogenic bacteria in the ulcers. Our findings suggest that this slow-release biopolymer is safe and of possible benefit in the management of refractory wounds, and they support the apparent utility of bacteriophages in this setting. Further studies, including carefully designed clinical trials, will be required to rigorously evaluate the efficacy of this novel wound dressing preparation.

A series of novel biodegradable unsaturated poly(ester amide)s (UPEAs) were synthesized through the solution polycondensation of two unsaturated monomers, di-p-nitrophenyl fumarate and L-phenylalanine 2-butene-1,4-diol diester p-toluene sulfonate, and four other saturated monomers in different combinations. The UPEAs were obtained in fairly good yields with N,N-dimethylacetamide (DMA) as the solvent. The number-average and weight-average molecular weights of the UPEAs, measured by gel permeation chromatography, ranged from 10 to 30 kg/mol, they had a rather narrow molecular weight distribution of 1.40. The chemical structures of the novel biodegradable UPEAs were confirmed by both IR and NMR spectra. The UPEAs had higher glass-transition temperatures than saturated PEAs of similar structures, and their glass-transition temperatures were affected more by the CAC double bond located in the diamide part than by those in the diester part. The solubility of the polymers was poor in water but better in DMA and dimethyl sulfoxide. With the availability of these inherent CAC double bonds in the UPEA backbones, these UPEAs have the functionality of CAC bonds, such as photochemical reactivity or the ability to react with or be modified by other bioactive or other environmentally sensitive compounds, and this can easily extend their applications to biomedical and pharmaceutical areas.

Poly(alkylene dicarboxylate)s constitute a family of biodegradable polymers with increasing interest for both commodity and speciality applications. Most of these polymers can be prepared from biobased diols and dicarboxylic acids such as 1,4-butanediol, succinic acid and carbohydrates. This review provides a current status report concerning synthesis, biodegradation and applications of a series of polymers that cover a wide range of properties, namely, materials from elastomeric to rigid characteristics that are suitable for applications such as hydrogels, soft tissue engineering, drug delivery systems and liquid crystals. Finally, the incorporation of aromatic units and α-amino acids is considered since stiffness of molecular chains and intermolecular interactions can be drastically changed. In fact, poly(ester amide)s derived from naturally occurring amino acids offer great possibilities as biodegradable materials for biomedical applications which are also extensively discussed.