Environmental problems, such as global warming and plastic pollution have forced researchers to investigate alternatives for conventional plastics. Poly(lactic acid) (PLA), one of the well-known eco-friendly biodegradables and biobased polyesters, has been studied extensively and is considered to be a promising substitute to petroleum-based polymers. This review gives an inclusive overview of the current research of lactic acid and lactide dimer techniques along with the production of PLA from its monomers. Melt polycondensation as well as ring opening polymerization techniques are discussed, and the effect of various catalysts and polymerization conditions is thoroughly presented. Reaction mechanisms are also reviewed. However, due to the competitive decomposition reactions, in the most cases low or medium molecular weight (MW) of PLA, not exceeding 20,000–50,000 g/mol, are prepared. For this reason, additional procedures such as solid state polycondensation (SSP) and chain extension (CE) reaching MW ranging from 80,000 up to 250,000 g/mol are extensively investigated here. Lastly, numerous practical applications of PLA in various fields of industry, technical challenges and limitations of PLA use as well as its future perspectives are also reported in this review.

The sustained release of pharmaceutical substances remains the most convenient way of drug delivery. Hence, a great variety of reports can be traced in the open literature associated with drug delivery systems (DDS). Specifically, the use of microparticle systems has received special attention during the past two decades. Polymeric microparticles (MPs) are acknowledged as very prevalent carriers toward an enhanced bio-distribution and bioavailability of both hydrophilic and lipophilic drug substances. Poly(lactic acid) (PLA), poly(lactic-co-glycolic acid) (PLGA), and their copolymers are among the most frequently used biodegradable polymers for encapsulated drugs. This review describes the current state-of-the-art research in the study of poly(lactic acid)/poly(lactic-co-glycolic acid) microparticles and PLA-copolymers with other aliphatic acids as drug delivery devices for increasing the efficiency of drug delivery, enhancing the release profile, and drug targeting of active pharmaceutical ingredients (API). Potential advances in generics and the constant discovery of therapeutic peptides will hopefully promote the success of microsphere technology.

In recent decades, scientific interest has increasingly focused on sustainable and green polymers. Within this context, considerable efforts have been devoted to the synthesis and exploration of eco-friendly non-isocyanate polyurethanes (NIPUs) as alternatives to conventional polyurethanes (PUs), solving the problem of isocyanate toxicity and other environmental problems that existed. This review article highlights the synthetic pathways of NIPUs and identifies the potential hazards associated with their production and end-of-life (EoL) stages. While in the literature there are several reviews regarding the synthesis of NIPUs, the current work distinguishes itself by providing a comprehensive summary of the latest research on NIPUs, with a particular focus on their lifecycle management, recyclability, and the challenges that hinder their scalability for industrial-level production. Advances in NIPU synthesis have made them strong candidates for a diverse range of applications. This review underscores the most notable examples of these advancements, emphasizing their potential to drive sustainable polymer development.

In the present study, a series of semisolid Oil in Water (O/W) emulsions containing different Curcumin (Cur) derivatives (Cur powder, Cur extract and Cur complexed with β-cyclodextrin) in varying concentrations, were prepared. Initially, Dynamic Light Scattering (DLS), microscopy, pH and viscosity measurements were performed to evaluate their stability over time. Moreover, the effect of the active cosmetic substances on the Sun Protection Factor (SPF), antimicrobial and antioxidant properties of the prepared emulsions was investigated. It was observed that emulsions containing Cur extract and Cur β-cyclodextrin complex presented great viscosity and pH stability for up to 90 days of storage contrary to the emulsions containing Cur powder which showed unstable behavior due to the formation of agglomerates. All samples presented SPF values between 2.6 and 3.2. The emulsions with Cur in all forms exhibited high antioxidant activity, whereas the emulsion containing Cur β-cyclodextrin complex presented the highest value. Despite their improved stability and antioxidant activity, the emulsions containing Cur extract and Cur-β-cyclodextrin exhibited a low percentage of antimicrobial activity against E. coli and Staphylococcus bacteria. Instead, the emulsions containing Cur powder presented a reduction rate over 90 % against E. coli and Staphylococcus colonies.

In the present study, polymer sponges based on poly(vinyl alcohol) (PVA) were prepared for the topical wound administration of chloramphenicol (CHL), an antibiotic widely used to treat bacterial infections. Nanocellulose fibrils (CNF) were homogenously dispersed in PVA sponges in three different ratios (2.5, 5, and 10 wt %) to improve the mechanical properties of neat PVA sponges. Infrared spectroscopy showed hydrogen bond formation between CNF and PVA, while scanning electron microscopy photos verified the successful dispersion of CNF to PVA sponges. The addition of CNF successfully enhanced the mechanical properties of PVA sponges, exhibiting higher compressive strength as the content of CNF increased. The PVA sponge containing 10 wt % CNF, due to its higher compression strength, was further studied as a matrix for CHL delivery in 10, 20, and 30 wt % concentration of the drug. X-ray diffraction showed that CHL was encapsulated in an amorphous state in the 10 and 20 wt % samples, while some crystallinity was observed in the 30 wt % ratio. In vitro dissolution studies showed enhanced CHL solubility after its incorporation in PVA/10 wt % CNF sponges. Release profiles showed a controlled release lasting three days for the sample containing 10 wt % CHL and 1.5 days for the other two samples. According to modelling, the release is driven by a pseudo-Fickian diffusion.

The present work describes the synthesis of poly(butylene succinate) (PBSu)-cutin copolymers by the two-stage melt polycondensation method, esterification and polycondensation. Cutin was added in four different concentrations, 2.5, 5, 10, and 20 wt%, in respect to succinic acid. The obtained copolymers were studied using a variety of techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), polarized light microscopy (PLM), as well as diffuse reflectance spectroscopy (DRS). A series of results, in agreement between different techniques, revealed the formation of PBSu-cutin interactions, confirming indirectly the successful in situ synthetic route of copolymers. DSC and XRD combined with PLM results provided indications that the crystallization temperature increases with the addition of small amounts of cutin and gradually decreases with increasing concentration. The crystallization process was easier and faster at 2.5%, 5%, and 10% concentrations, whereas at 20%, it was comparable to neat PBSu. The presence of cutin, in general, leads to the facilitated crystallizability of PBSu (direct effect), whereas a moderate drop in the glass transition temperature is recorded, the latter being an indirect effect of cutin via crystallization. The thermal stability improved in the copolymers compared to neat PBSu. Water contact angle measurements confirmed that the addition of cutin decreased the hydrophilicity. The local and segmental relaxation mapping is demonstrated for PBSu/cutin here for the first time. Enzymatic hydrolysis and soil degradation tests showed that, overall, cutin accelerated the decomposition of the polymers. The copolymers may be proven useful in several applications.