Recent complications on the use of polypropylene meshes for hernia repair has led to the development of meshes or films, which were based on resorbable polymers such as polycaprolactone (PCL), polylactic acid (PLA) and poly(lactic-co-glycolic acid) (PLGA). These materials are able to create suitable bioactive environment for the growth and development of cells. In this research, we mainly focused on the relations among structure, mechanical performance and biocompatiblity of PCL/PLA and PCL/PLGA and blends prepared by solution casting. The films were characterized regarding the chemical structure, morphology, physicochemical properties, cytotoxicity, biocompatibility and cell growth. All the films showed high tensile strength ranging from 9.5 to 11.8 MPa. SAXS showed that the lamellar stack structure typical for PCL was present even in the blend films while the morphological parameters of the stacks varied slightly with the content of PLGA or PLA in the blends. WAXS indicated preferential orientation of crystallites (and thus, also the lamellar stacks) in the blend films. In vitro studies revealed that PCL/PLGA films displayed better cell adhesion, spreading and proliferation than PCL/PLA and PCL films. Further the effect of blending on the degradation was investigated, to understand the significant variable within the process that could provide further control of cell adhesion. The results showed that the investigated blend films are promising materials for biomedical applications.

• Klíčová slova
• Biocompatibility, Mechanical properties, Nanoscale morphology, Polycaprolactone, Resorbable blends,
• MeSH
• difrakce rentgenového záření MeSH
• glykoly * MeSH
• kopolymer kyseliny glykolové a mléčné MeSH
• maloúhlový rozptyl MeSH
• polyestery MeSH
• vstřebatelné implantáty * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glykoly * MeSH
• kopolymer kyseliny glykolové a mléčné MeSH
• poly(lactide) MeSH Prohlížeč
• polycaprolactone MeSH Prohlížeč
• polyestery MeSH

Poly(lactic-co-glycolic acid) (PLGA) is a US Food and Drug Administration (FDA)-approved polymer used in humans in the forms of resorbable sutures, drug carriers, and bone regeneration materials. Recently, PLGA-based conjugates have been extensively investigated for cancer, which is the second leading cause of death globally. This article presents an account of the literature on PLGA-based conjugates, focusing on their chemistries, biological activity, and functions as targeted drug carriers or sustained drug controllers for common cancers (e.g., breast, prostate, and lung cancers). The preparation and drug encapsulation of PLGA nanoparticles and folate-decorated poly(ethylene glycol)-poly(lactic-co-glycolic acid) (FA-PEG-PLGA) conjugates are discussed, along with several representative examples. Particularly, the reactions used for preparing drug-conjugated PLGA and FA-PEG-PLGA are emphasized, with the associated chemistries involved in the formation of structures and their biocompatibility with internal organs. This review provides a deeper understanding of the constituents and interactions of PLGA-conjugated materials to ensure successful conjugation in PLGA material design and the subsequent biomedical applications.

• MeSH
• kopolymer kyseliny glykolové a mléčné MeSH
• kyselina listová chemie   MeSH
• lidé MeSH
• nádory * MeSH
• nanočástice * chemie   MeSH
• nosiče léků chemie   MeSH
• polyethylenglykoly chemie   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Geografické názvy
• Spojené státy americké MeSH
• Názvy látek
• kopolymer kyseliny glykolové a mléčné MeSH
• kyselina listová MeSH
• nosiče léků MeSH
• polyethylenglykoly MeSH

Commercially available antibacterial semisolid preparations intended for topical application provide only short-term drug release. A sustained kinetics is possible by exploitation of a biodegradable polymer carrier. The purpose of this work is to formulate a mucoadhesive system with aciclovir (ACV) based on a solid molecular dispersion of this drug in poly(lactic-co-glycolic acid) branched on tripenterythritol (PLGA/T). The ACV incorporation into PLGA/T was carried out either by solvent method, or melting method, or plasticization method using various plasticizers. The drug-polymer miscibility, plasticizer efficiency and content of residual solvent were found out employing DSC. Viscosity was measured at the shear rate range from 0.10 to 10.00 s(-1) at three temperatures and data were analyzed by Newtonian model. The mucoadhesive properties were ascertained in the tensile test on a mucin substrate. The amount of ACV released was carried out in a wash-off dissolution test. The DSC results indicate a transformation of crystalline form of ACV into an amorphous dissolved in branched polyester carrier, and absence of methyl formate residuals in formulation. All the tested plasticizers are efficient at Tg depression and viscosity decrease. The non-conventional ethyl pyruvate possessing supportive anti-inflammatory activity was evaluated as the most suitable plasticizer. The ACV release was strongly dependent on the ethyl pyruvate concentration and lasted from 1 to 10 days. The formulated PLGA/T system with ACV exhibits increased adhesion to mucosal hydrophilic surfaces and prolonged ACV release controllable by degradation process and viscosity parameters.

• Klíčová slova
• Acyclovir, branched molecule, drug release, ethyl pyruvate, mucoadhesivity, plasticization, poly(lactic-co-glycolic acid), solid dispersion,
• MeSH
• acyklovir aplikace a dávkování   chemie   MeSH
• biokompatibilní materiály chemie   MeSH
• časové faktory MeSH
• hydrofobní a hydrofilní interakce MeSH
• kopolymer kyseliny glykolové a mléčné MeSH
• kyselina mléčná chemie   MeSH
• kyselina polyglykolová chemie   MeSH
• léky s prodlouženým účinkem MeSH
• povrchové vlastnosti MeSH
• uvolňování léčiv MeSH
• velikost částic MeSH
• změkčovadla aplikace a dávkování   chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acyklovir MeSH
• biokompatibilní materiály MeSH
• kopolymer kyseliny glykolové a mléčné MeSH
• kyselina mléčná MeSH
• kyselina polyglykolová MeSH
• léky s prodlouženým účinkem MeSH
• změkčovadla MeSH

The aim of this study was to fabricate novel microparticles (MPs) for efficient and long-term delivery of amikacin (AMI). The emulsification method proposed for encapsulating AMI employed low-molecular-weight poly(lactic acid) (PLA) and poly(lactic acid-co-polyethylene glycol) (PLA-PEG), both supplemented with poly(vinyl alcohol) (PVA). The diameters of the particles obtained were determined as less than 30 μm. Based on an in-vitro release study, it was proven that the MPs (both PLA/PVA- and PLA-PEG/PVA-based) demonstrated long-term AMI release (2 months), the kinetics of which adhered to the Korsmeyer-Peppas model. The loading efficiencies of AMI in the study were determined at the followings levels: 36.5 ± 1.5 μg/mg for the PLA-based MPs and 106 ± 32 μg/mg for the PLA-PEG-based MPs. These values were relatively high and draw parallels with studies published on the encapsulation of aminoglycosides. The MPs provided antimicrobial action against the Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae bacterial strains. The materials were also comprehensively characterized by the following methods: differential scanning calorimetry; gel permeation chromatography; scanning electron microscopy; Fourier transform infrared spectroscopy-attenuated total reflectance; energy-dispersive X-ray fluorescence; and Brunauer-Emmett-Teller surface area analysis. The findings of this study contribute toward discerning new means for conducting targeted therapy with polar, broad spectrum antibiotics.

• Klíčová slova
• amikacin encapsulation, drug delivery systems, microparticles, poly(lactic acid), targeted therapy,
• MeSH
• amikacin aplikace a dávkování   chemie   MeSH
• antibakteriální látky aplikace a dávkování   chemie   MeSH
• Escherichia coli účinky léků   MeSH
• Klebsiella pneumoniae účinky léků   MeSH
• laktáty chemie   MeSH
• mikrobiální testy citlivosti MeSH
• molekulová hmotnost MeSH
• nosiče léků chemie   MeSH
• polyestery chemie   MeSH
• polyethylenglykoly chemie   MeSH
• polyvinylalkohol chemie   MeSH
• příprava léků metody   MeSH
• Pseudomonas aeruginosa účinky léků   MeSH
• rozpustnost MeSH
• Staphylococcus aureus účinky léků   MeSH
• tobolky MeSH
• uvolňování léčiv MeSH
• velikost částic MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• amikacin MeSH
• antibakteriální látky MeSH
• laktáty MeSH
• nosiče léků MeSH
• poly(lactic acid-ethylene glycol) MeSH Prohlížeč
• poly(lactide) MeSH Prohlížeč
• polyestery MeSH
• polyethylenglykoly MeSH
• polyvinylalkohol MeSH
• tobolky MeSH

Prediction of poly(lactic-co-glycolic acid) (PLGA) micro- and nanoparticles' dissolution rates plays a significant role in pharmaceutical and medical industries. The prediction of PLGA dissolution rate is crucial for drug manufacturing. Therefore, a model that predicts the PLGA dissolution rate could be beneficial. PLGA dissolution is influenced by numerous factors (features), and counting the known features leads to a dataset with 300 features. This large number of features and high redundancy within the dataset makes the prediction task very difficult and inaccurate. In this study, dimensionality reduction techniques were applied in order to simplify the task and eliminate irrelevant and redundant features. A heterogeneous pool of several regression algorithms were independently tested and evaluated. In addition, several ensemble methods were tested in order to improve the accuracy of prediction. The empirical results revealed that the proposed evolutionary weighted ensemble method offered the lowest margin of error and significantly outperformed the individual algorithms and the other ensemble techniques.

• Klíčová slova
• ensemble, feature selection, protein dissolution, regression models,
• MeSH
• algoritmy MeSH
• kopolymer kyseliny glykolové a mléčné MeSH
• kyselina mléčná chemie   MeSH
• kyselina polyglykolová chemie   MeSH
• mikrosféry MeSH
• nanočástice chemie   MeSH
• rozpustnost MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kopolymer kyseliny glykolové a mléčné MeSH
• kyselina mléčná MeSH
• kyselina polyglykolová MeSH

Orotic acid is a natural heterocyclic compound that acts as a nucleation agent in poly(lactic acid) (PLA). PLA materials with increasing orotic acid content were prepared and characterized. It was found that crystallinity of about 28% was reached with 0.3% content of the agent. Further enhancement in the content of the agent did not provoke any additional significant increase of crystallinity. Subsequently, it was investigated whether the orotic acid content affected photodegradation of PLA and, in the next phase, its biodegradation. The results of rheological measurements showed that the compound slightly accelerates photodegradation of the material, which was accompanied by the cleavage of PLA chains. Previous photodegradation was shown to accelerate the subsequent biodegradation by shortening the lag phase of the process, where the explanation is probably in the reduction of the polymer molecular weight during the photodegradation. Moreover, the presence of orotic acid in both initial and photodegraded samples was found to influence biodegradation positively by shortening the lag phase and increasing the observed maximal rate of the biodegradation.

• Klíčová slova
• biodegradation, compost, crystallinity, orotic acid, photodegradation, poly(lactic acid),
• Publikační typ
• časopisecké články MeSH

Poly(lactic acid)-block-poly(oxirane)s (PLA-b-POE) of various compositions were prepared using a one-pot approach and then extended in a reaction with l-lysine diethyl ester diisocyanate, thereby forming polyester-ether-urethanes (PEU) with prolonged chains and units with increased degradability. The PEUs are processed by electrospinning to prepare degradable nanofibrous sheet materials with and without encapsulating the antibiotic Vancomycin (VAC). PLA block isomerism and POE blocks oligomeric content (1000 g/mol) affect the thermal properties, processability, nanofibrous sheet morphology, abiotic degradation, cytocompatibility, and encapsulated antibiotic release rate of prepared PEUs. Therefore, our findings provide an effective approach to tuning the functional properties of these advanced biocompatible materials. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2378-2387, 2019.

• Klíčová slova
• abiotic, degradation, drug delivery, electrospinning, nanofibers, poly(lactic acid), polyester-urethanes, vancomycin,
• MeSH
• antibakteriální látky * chemie   farmakologie   MeSH
• buňky NIH 3T3 MeSH
• lékové transportní systémy * MeSH
• myši MeSH
• nanovlákna chemie   MeSH
• polyestery chemie   farmakologie   MeSH
• polyethylenglykoly chemie   farmakologie   MeSH
• polyurethany chemie   farmakologie   MeSH
• testování materiálů * MeSH
• vankomycin * chemie   farmakologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antibakteriální látky * MeSH
• poly(lactide) MeSH Prohlížeč
• polyestery MeSH
• polyethylenglykoly MeSH
• polyurethany MeSH
• vankomycin * MeSH

The biodegradation of four poly(l-lactic acid) (PLA) samples with molecular weights (MW) ranging from approximately 34 to 160kgmol(-1) was investigated under composting conditions. The biodegradation rate decreased, and initial retardation was discernible in parallel with the increasing MW of the polymer. Furthermore, the specific surface area of the polymer sample was identified as the important factor accelerating biodegradation. Microbial community compositions and dynamics during the biodegradation of different PLA were monitored by temperature gradient gel electrophoresis, and were found to be virtually identical for all PLA materials and independent of MW. A specific PLA degrading bacteria was isolated and tentatively designated Thermopolyspora flexuosa FTPLA. The addition of a limited amount of low MW PLA did not accelerate the biodegradation of high MW PLA, suggesting that the process is not limited to the number of specific degraders and/or the induction of specific enzymes. In parallel, abiotic hydrolysis was investigated for the same set of samples and their courses found to be quasi-identical with the biodegradation of all four PLA samples investigated. This suggests that the abiotic hydrolysis represented a rate limiting step in the biodegradation process and the organisms present were not able to accelerate depolymerization significantly by the action of their enzymes.

• Klíčová slova
• Abiotic hydrolysis, Biodegradation, Polylactic acid,
• MeSH
• Bacteria metabolismus   MeSH
• biodegradace MeSH
• biopolymery chemie   MeSH
• časové faktory MeSH
• hydrolýza MeSH
• kyselina mléčná chemie   MeSH
• teplota MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biopolymery MeSH
• kyselina mléčná MeSH

PURPOSE: The present study aims to prepare poly(D,L-lactic acid) (PLA) nanofibers loaded by the immunosuppressant cyclosporine A (CsA, 10 wt%). Amphiphilic poly(ethylene glycol)s (PEG) additives were used to modify the hydrophobic drug release kinetics. METHODS: Four types of CsA-loaded PLA nanofibrous carriers varying in the presence and molecular weight (MW) of PEG (6, 20 and 35 kDa) were prepared by needleless electrospinning. The samples were extracted for 144 h in phosphate buffer saline or tissue culture medium. A newly developed and validated LC-MS/MS method was utilized to quantify the amount of released CsA from the carriers. In vitro cell experiments were used to evaluate biological activity. RESULTS: Nanofibers containing 15 wt% of PEG showed improved drug release characteristics; significantly higher release rates were achieved in initial part of experiment (24 h). The highest released doses of CsA were obtained from the nanofibers with PEG of the lowest MW (6 kDa). In vitro experiments on ConA-stimulated spleen cells revealed the biological activity of the released CsA for the whole study period of 144 h and nanofibers containing PEG with the lowest MW exhibited the highest impact (inhibition). CONCLUSIONS: The addition of PEG of a particular MW enables to control CsA release from PLA nanofibrous carriers. The biological activity of CsA-loaded PLA nanofibers with PEG persists even after 144 h of previous extraction. Prepared materials are promising for local immunosuppression in various medical applications.

• Klíčová slova
• LC-MS/MS, cyclosporine A, drug release kinetics, poly(D,L-lactic acid) nanofibers, poly(ethylene glycol),
• MeSH
• buněčné linie MeSH
• cyklosporin aplikace a dávkování   chemie   MeSH
• hydrofobní a hydrofilní interakce MeSH
• imunosupresiva aplikace a dávkování   chemie   MeSH
• kinetika MeSH
• kultivační média MeSH
• lidé MeSH
• nanovlákna chemie   MeSH
• nosiče léků MeSH
• polyestery chemie   MeSH
• polyethylenglykoly chemie   MeSH
• povrchové vlastnosti MeSH
• slezina cytologie   MeSH
• techniky tkáňových kultur MeSH
• uvolňování léčiv MeSH
• velikost částic MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cyklosporin MeSH
• imunosupresiva MeSH
• kultivační média MeSH
• nosiče léků MeSH
• poly(lactide) MeSH Prohlížeč
• polyestery MeSH
• polyethylenglykoly MeSH

A more recent insight into the structural differences of sustainable poly(lactic acid)-based materials was revealed through a solvolysis reaction under environmentally friendly conditions. The decomposition process clarified the heterogeneous structure of the investigation polymers. It was found that materials used for nanofiber production degraded 25 % more poorly compared to materials suitable for packaging materials. The resultant product, ethyl lactate, demonstrated high purity and yield (up to 900 mg·L-1, 98 %). The degree and effect of decomposition of the poly(lactic acid) were monitored by employing the gel permeation chromatic method, differential scanning calorimetry and thermal gravimetric analysis. X-ray diffraction was conducted to assess differences between the crystalline portions of polymers. The yield and purity of the product were verified by gas and liquid chromatography. The kinetic studies evaluated the rate of polymers degradation connected with chemical structure and temperature. A structural difference was observed in the studied polylactides, with approximately a 15 % deviation in crystallinity. This observed variation resulted from differences in arrangement and chain lengths, as well as the terminal functional groups, leading to non-uniform degradation of both polymers. This study offers a new insight on the degradation efficiency of polymers highlights the non-uniformity of their structure. Converting biodegradable polymer waste into a suitable and reusable product as part of an environmentally friendly approach will contribute to the sustainability of polymer materials.

• Klíčová slova
• Architecture, Crystallinity, Degradation, sustainable materials, Environmentally friendly, Poly(lactic acid), Solvolysis,
• MeSH
• diferenciální skenovací kalorimetrie MeSH
• difrakce rentgenového záření MeSH
• kinetika MeSH
• laktáty MeSH
• polyestery * chemie   MeSH
• rozpouštědla * chemie   MeSH
• teplota MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ethyl lactate MeSH Prohlížeč
• laktáty MeSH
• poly(lactide) MeSH Prohlížeč
• polyestery * MeSH
• rozpouštědla * MeSH