Azelaic acid is a dicarboxylic acid containing nine C atoms, industrially obtained from oleic acid. Besides its important properties and pharmacological applications, as an individual compound, azelaic acid has proved to be a valuable bio-based monomer for the synthesis of biodegradable and sustainable polymers, plasticizers and lubricants. This review discusses the studies and the state of the art in the field of the production of azelaic acid from oleic acid, the chemical and enzymatic synthesis of bio-based oligo and polyester and their properties, including biodegradability and biocompostability.

Azelaic acid (AzA), a saturated dicarboxylic acid, is indicated for the treatment of acne vulgaris, rosacea, melasma, and post-inflammatory hyperpigmentation. Its antimicrobial, anti-inflammatory, and antimelanogenic properties support its use; however, its poor aqueous solubility and limited skin permeability constrain its optimal topical delivery. This review summarizes clinical evidence and advances in formulations—including conventional vehicles, polymeric/lipid nanocarriers, and deep eutectic solvent (DES) systems—to promote more effective and well-tolerated use. Across indications, 15–20% azelaic acid (AzA) formulations produced clinically meaningful improvements with mild, transient local irritation. For acne vulgaris, reductions in inflammatory and noninflammatory lesions were comparable to those of topical retinoids/adapalene, and tolerability was superior in some studies. For rosacea, the 15% gel formulation was comparable to metronidazole in reducing papules, pustules, and erythema while maintaining negligible systemic exposure. In melasma and other dyschromias, 20% cream demonstrated efficacy similar to hydroquinone, exhibiting a favorable safety profile. Advanced delivery systems, including liposomes, niosomes/ethosomes, nanostructured lipid carriers, microemulsions, nanosponges, and DES platforms, increased AzA solubilization, cutaneous deposition, and stability. This enabled dose-sparing strategies and improved adherence. Data on AzA cocrystals and ionic salts suggest additional control over release and irritation. AzA remains a versatile and well-tolerated dermatologic agent whose performance is strongly vehicle-dependent. Rational selection and engineering of carriers, particularly DES-integrated polymeric and lipid systems, can mitigate solubility and permeability limitations, enhance skin targeting, and reduce irritation in the treatment of acne and rosacea.

Following the latest developments, bio-based polyesters, obtained from renewable raw materials, mainly carbohydrates, can be competitive for the fossil-based equivalents in various industries. In particular, the furan containing monomers are valuable alternatives for the synthesis of various new biomaterials, applicable in food additive, pharmaceutical and medical field. The utilization of lipases as biocatalysts for the synthesis of such polymeric compounds can overcome the disadvantages of high temperatures and metal catalysts, used by the chemical route. In this work, the enzymatic synthesis of new copolymers of ε-caprolactone and 5-hydroxymethyl-2-furancarboxylic acid has been investigated, using commercially available immobilized lipases from Candida antarctica B. The reactions were carried out in solvent-less systems, at temperatures up to 80 °C. The structural analysis by MALDI TOF-MS, NMR, and FT-IR spectroscopy confirmed the formation of cyclic and linear oligoesters, with maximal polymerization degree of 24 and narrow molecular weight distribution (dispersity about 1.1). The operational stability of the biocatalyst was explored during several reuses, while thermal analysis (TG and DSC) indicated a lower thermal stability and higher melting point of the new products, compared to the poly(ε-caprolactone) homopolymer. The presence of the heterocyclic structure in the polymeric chain has promoted both the lipase-catalyzed degradation and the microbial degradation. Although, poly(ε-caprolactone) is a valuable biocompatible polymer with important therapeutic applications, some drawbacks such as low hydrophilicity, low melting point, and relatively slow biodegradability impeded its extensive utilization. In this regard the newly synthesized furan-based oligoesters could represent a “green” improvement route.

New technologies for the conversion of biomass into high-value chemicals, including polymers and plastics, is a must and a challenge. The development of green processes in the last decade involved a continuous increase of the interest towards the synthesis of polymers using in vitro biocatalysis. Among the remarkable diversity of new bio-based polymeric products meeting the criteria of sustainability, biocompatibility, and eco-friendliness, a wide range of polyesters with shorter chain length were obtained and characterized, targeting biomedical and cosmetic applications. In this review, selected examples of such specialty polymers are presented, highlighting the recent developments concerning the use of lipases, mostly in immobilized form, for the green synthesis of ε-caprolactone co-polymers, polyesters with itaconate or furan units, estolides, and polyesteramides. The significant process parameters influencing the average molecular weights and other characteristics are discussed, revealing the advantages and limitations of biocatalytic processes for the synthesis of these bio-based polymers.