Comprehensive comparison of antioxidant properties of tinctures

Homemade tinctures, traditional Polish alcoholic beverages called “nalewkas” (similar to alcohol herbal tinctures), which antioxidant capacity have never been studied before, were characterized by electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR) and ultraviolet visible (UV-vis) spectroscopy. The antioxidant properties of nalewkas made according to homemade recipes were compared to commercially produced nalewkas. The impact of aging on antioxidant properties of nalewkas was investigated. The results showed that all of examined nalewkas exhibited strong antioxidant properties (antioxidant capacity TEACDPPH 466 μmol TE/100 mL – 11890 μmol TE/100 mL). It was found that the value of the antioxidant capacity corresponds to the total phenolic and aromatic proton content. The impact of the production method and the type of fruit used on the TEACDPPH value was also noted. The unripe walnuts with green husks has the highest value of the antioxidant capacity TEACDPPH (11890 μM/100 mL) not only for alcoholic beverages, but also among food products

Pressure-assisted solvent- and catalyst-free production of well-defined poly(1-vinyl-2-pyrrolidone) for biomedical applications

In this work, we developed a fast, highly efficient, and environmentally friendly catalytic systemfor classical freeradical polymerization (FRP) utilizing a high-pressure (HP) approach. The application of HP for thermallyinduced, bulk FRP of 1-vinyl-2-pyrrolidone (VP) allowed to eliminate the current limitation of ambientpressure polymerization of ‘less-activated’ monomer (LAM), characterized by the lack of temporal control yielding polymers of unacceptably large disperisites and poor result reproducibility. By a simple manipulation of thermodynamic conditions (p ¼ 125–500 MPa, T ¼ 323–333 K) and reaction composition (twocomponent system: monomer and low content of thermoinitiator) well-defined poly(1-vinyl-2-pyrrolidone)s (PVP) in a wide range of molecular weights and low/moderate dispersities (Mn ¼ 16.2–280.5 kg mol 1, Đ ¼ 1.27–1.45) have been produced. We have found that HP can act as an ‘external’ controlling factor that warrants the first-order polymerization kinetics for classical FRP, something that was possible so far only for reversible deactivation radical polymerization (RDRP) systems. Importantly, our synthetic strategy adopted for VP FRP enabled us to obtain polymers of very high Mn in a very short time-frame (0.5 h). It has also been confirmed that VP bulk polymerization yields polymers with significantly lower glass transition temperatures (Tg) and different solubility properties in comparison to macromolecules obtained during the solvent-assisted reaction

High pressure as a novel tool for the cationic ROP of γ-butyrolactone

In this study, we report the acid-catalyzed and high pressure assisted ring-opening polymerization (ROP) of g-butyrolactone (GBL). The use of a dually-catalyzed approach combining an external physical factor and internal catalyst (trifluoromethanesulfonic acid (TfOH) or p-toluenesulfonic acid (PTSA)) enforced ROP of GBL, which is considered as hardly polymerizable monomer still remaining a challenge for the modern polymer chemistry. The experiments performed at various thermodynamic conditions (T ¼ 278–323 K and p ¼ 700–1500 MPa) clearly showed that the high pressure supported polymerization process led to obtaining well-defined macromolecules of better parameters (Mn ¼ 2200–9700 g mol 1; Đ ¼ 1.05–1.46) than those previously reported. Furthermore, the parabolic-like dependence of both the molecular weight (MW) and the yield of obtained polymers on variation in temperature and pressure at either isobaric or isothermal conditions was also noticed, allowing the determination of optimal conditions for the polymerization process. However, most importantly, this strategy allowed to significantly reduce the reaction time (just 3 h at room temperature) and increase the yield of obtained polymers (up to 0.62 gPGBL/gGBL). Moreover, despite using a strongly acidic catalyst, synthesized polymers remained non-toxic and biocompatible, as proven by the cytotoxicity test we performed in further analysis. Additional investigation (including MALDI-TOF measurements) showed that the catalyst selection affected not only MW and yield but also the linear/cyclic form content in obtained macromolecules. These findings show the way to tune the properties of PGBL and obtain polymer suitable for application in the biomedical industry

Synthetic strategy matters : the study of a different kind of PVP as micellar vehicles of metronidazole

Poly(1-vinyl-2-pyrrolidone) (Povidone, PVP) is one of the most interesting and versatile synthetic polymers utilised in the pharmaceutical and cosmetic industries. Its large-scale commercial production offers an assortment of products in a wide range of molecular weights but poorly-controlled (macro)structural parameters (i.e., dispersity, functionality) limiting the efficiency of PVP-based drug delivery systems (DDS). In this work, synthesised linear and star-shaped PVPs with a strictly defined structure and functionality were compared with the linear, commercially-supplied product and explored as potential vehicles for physical entrapment of metronidazole (MTZ). Here, a question is addressed how differences in their macromolecular properties affect the amorphisation of MTZ, drug encapsulation, the stability of drug-loaded micellar structures and their in vitro release from the carrier. The X-ray diffraction studies and calorimetric measurements revealed that MTZ crystallises in all investigated herein systems reducing the glass transition temperature of the binary mixture significantly. Transmission electron microscopy and dynamic light scattering analysis revealed that MTZ-loaded DDS are able to form ultrasmall regular nanocarriers with an increasing effect of regularity and sphericity from star-shaped DDS to linear-based ones. We founded that synthesised linear-based DDS is the most effective for MTZ entrapment (PVP:MTZ = 1:1 weight ratio) due to their smallest hydrodynamic radius dh = 14.7 nm, the highest stability of micellar structures −2.37 mV, and the highest values of loaded drug 76.5%. Moreover, all applied PVP-based DDS revealed an initial burst release effect of MTZ (pH = 7.4) reaching up to 60% of drug released within the first 5 h (the first-order release model fits). The marked efficiency of MTZ-loaded DDS of strictly defined structural parameters indicates the great importance of polymer preparation strategy in the targeted therapy

The effect of high-pressure on organocatalyzed ROP of γ-butyrolactone

In this paper, we report 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) supported high-pressure approach enforcing Ring-Opening Polymerization (ROP) of γ-butyrolactone (GBL), that due to unfavorable thermodynamics and low ring strain, is considered as a hardly polymerizable monomer. Application of Broadband Dielectric Spectroscopy (BDS) allowed us to find optimal thermodynamic conditions to perform well-controlled and notably fast polymerization (even within 1 h!), avoiding undesired crystallization process. It was shown that by varying pressure and temperature conditions, we could control molecular weight, dispersity of recovered macromolecules, as well as rate and efficiency of the reaction that are significantly altered with respect to the reference process carried out at ambient conditions. Experiments performed at respectively very low temperature T = 233 K and low/ moderate pressure (p = 75–250 MPa) and much higher temperatures (T = 248–268 K) and compressions (p = 1000 MPa) yielded poly(γ-butyrolactone) (PGBL) of tailored absolute molecular weight in moderate range Mn = 2.8–15.0 (up to 30.3) kg/mol and narrow/moderate dispersity ranging from Đ = 1.12–1.89. What is more, the implementation of MALDI-TOF, GPC and DSC analyses, clearly indicated that as i) the time of reaction gets longer, ii) the amount of catalyst increases, iii) the temperature lowers, the content of cyclic products in produced polymers grows. This phenomenon influences the rheological properties (viscosity), foil formation ability (films) and cell culture proliferation features of the recovered macromolecules. Presented results open a highly effective and repeatable route to produce PGBL via pressure-assisted ROP and indicate the possibility of tuning properties of this polymer by varying concentration of cycles or eventual block copolymerization with other biorelevant monomers to meet the expectations of the biotechnological industry

Wysokociśnieniowa metodologia syntezy ultraczystych materiałów polimerowych do zastosowań biomedycznych i farmaceutycznych

Praca zawiera artykuły w języku angielskim.Presented PhD dissertation consisting of a series of four scientific papers aimed to develop a unique synthetic strategy based on a dually-catalyzed approach combining an ‘internal’ non-toxic (organo)catalyst and ‘external’ physical factor (elevated pressure), inducing/controlling the course of the polymerization process of various types of monomers. This work is mainly focused on the polymerization of monomers classified as 'hardly-polymerizable' and ‘less activated', especially y-butyrolactone (GBL) and l-vinyl-2-pyrrolidone (VP) - being precursors of particularly important polymers intended for biomedical and pharmaceutical applications. The main goal of this work was to develop innovative, highly efficient and controlled methods of polymerization (GBL ring-opening polymerization (ROP) and VP free-radical polymerization (FRP)), allowing to obtain ultra-pure polymers of well-defined parameters (i.e. tailored molecular weight, dispersity and chain topology). The conducted research confirmed that the use of high pressure can force GBL ROP which is not possible at atmospheric pressure or proceeds with low efficiency, even at extremely low temperatures. The application of elevated pressure also enabled FRP of VP in a controlled manner yielding ultra-pure polymers of parameters currently unattainable in the industry (moderate dispersity) by applying a fast and efficient synthetic strategy without using any additional catalysts. The routine analysis of the obtained macromolecules (NMR, FT-IR, SEC-LALLS, MALDI-TOF) was extended to comprehensive, interdisciplinary research (including calorimetric, rheological and biological studies). It was also investigated if the polymer structure (topology and length of the PVP chains) affects both drug loading content and drug release profile and it was assessed as a key factor in the development of new formulations with active pharmaceutical ingredients. To sum up, the results of the research discussed in this dissertation clearly demonstrated that the use of system compression allows to i) overcome the thermodynamic limitations of 'hardly-polymerizable' systems, ii) reduce the reaction time and significantly increase the efficiency, Hi) produce of tailored polymers of better or even unique parameters (higher molecular weight and smaller dispersity) in comparison to the polymerization performer at ambient pressure, iv) simplify the reaction system and reduce/eliminate the necessity of using toxic reagents