Polymer Mixtures Research Articles

Optimization of nano-structured lipid carriers for enhanced salbutamol delivery via buccal mucoadhesive film

Salbutamol sulphate (SS) is a widely prescribed β2 agonist for different respiratory disorders. However, its short plasma half-life and poor oral bioavailability strongly limit its compliance. This study targeted formulating SS in nanostructured lipid carriers (SS-NLCs) embedded in a buccal mucoadhesive film to enhance bioavailability and sustain release through an easy route of administration aiming to improve patient compliance and reduce dose-related side effects. SS-NLCs were prepared using glycerol monostearate (GMS), Labrasol® oil, and poloxamer 407 utilizing a full 23 factorial design. Eight SS-loaded NLCs formulations were evaluated for particle size distribution, zeta potential, and entrapment efficiency. The optimum formula selected according to design expert® statistical analysis, was subsequently incorporated in a polymeric buccal mucoadhesive film and subjected to in vitro and in vivo characterization. The optimum SS-NLCs showed a mean particle size of 119.1 ± 1.28 nm, polydispersity index of 0.248 ± 0.023, zeta potential of - 40.9 ± 0.47 mV, and entrapment efficiency of 68.20 ± 2.05 % with apparent controlled release. Casting SS-NLCs in a mucoadhesive polymeric mixture resulted in a smooth strong film with a prolonged in vitro drug release duration reaching 10 h. In vivo, buccal application of the formulated film showed significantly higher Cmax (107.53 ± 5.20 ng/ml) and delayed Tmax to 4 h with improving the bioavailability of SS by 4.10 folds compared to oral SS solution. Consequently, the buccal polymeric mucoadhesive film of SS-NLCs holds promise as an alternative route for sustained release, enhancing bioavailability, and improving therapeutic efficacy in treating respiratory disorders.

Effects of binary polymer-humic soil amendments on soil carbon cycle and detoxication ability of heavy metal pollution

BackgroundSynthetic hydrophilic polyelectrolytes are considered as perspective tools to optimize soil properties and find increasing applications in agricultural technologies. One possible polyelectrolyte-based soil conditioner that has shown promise for improving soil hydrophysical properties is hydrolyzed polyacrylonitrile (HYPAN), linear polyanion. Combinations of HYPAN with humic substances in binary polymer-humic soil amendment presumably could provide a synergistic impact. In this study we investigated the effects of HYPAN, two different potassium humates (from lignite and lignosulfonate), and binary compositions of HYPAN with humates in the ratios of 1:1 and 1:2, on soil microbiological activity. We applied polymer solutions (0.9% on a dry matter basis) in a lab experiment and examined how they affected soil respiration, microbial biomass, metabolic quotient, and the decomposition rate constant in soil–polymer mixtures. A concurrent set of studies involved spiking soil–polymer mixes with heavy metals (copper, zinc, lead and cadmium).ResultsIn uncontaminated soil–polymer mixtures both humates stimulated the activity of soil microorganisms, expressed in increased basal respiration, microbial biomass, and mitigation of HM toxicity. The effects of binary polymer-humic formulations and HYPAN were comparable to and close in size to those of humates. On the 90th day, humates increased microbial respiration by 54–77% and HYPAN alone by 30%. Binary compositions were more efficient when combined with humate from lignosulphonate. The maximum increase in microbial biomass was obtained with the same humate both in composition and alone (65 and 91 µg C g−1). Under conditions of HM contamination at the end of the incubation, the levels of microbiological parameters in HM spiked soil–polymer mixtures did not statistically differ from the uncontaminated control. Every polymer formulation helped to partially restore microbial activity while reducing the toxic effects of HM. In these circumstances, humate from lignite both by itself and in combination with HYPAN performed better. The quality of organic matter in both humates and HYPAN was the primary determinant of the impact of the examined amendments.ConclusionsCombination of natural humate and synthetic HYPAN stimulated the activity of soil microorganisms, increased their biomass and mitigated the toxicity of heavy metals present in the soil. This allows the use of binary HYPAN-humate formulations to improve the chemical and biological properties of soil and increase its productivity.Graphical

Choline Chloride-Urea Deep Eutectic Solvent/Cu-Mn Iminodiacetate Coordination Polymer as an Efficient Catalytic System for Synthesis of Morita-Baylis-Hillman Adducts with Antimicrobial Activity.

This work shows the synthesis of a series of Morita-Baylis-Hillman adducts from isatin derivatives via an efficient green approach involving the use of a new catalyst system, a mixture of copper-manganese iminodiacetate 1D coordination polymer (Cu/Mn-IDA) and choline chloride-urea deep eutectic solvent (ChCl/urea 1:2). The adducts 2a-2i were obtained in good to excellent yields (59-97%) with shorter reaction times. The results demonstrate for the first time the synergistic catalytic effect of the combination of deep eutectic solvent and coordination polymer on the Morita-Baylis-Hillman reactions. The catalyst recyclability was investigated, and it was found that Cu/Mn-IDA maintains consistent performance for at least four catalytic cycles. The synthesized compounds were evaluated for their in vitro antimicrobial activity against four bacteria and eight fungi species. Among all, 2a, 2b, 2d, 2e, and 2g showed antifungal and antibacterial activities in 70-83% of the strains tested. The adduct 2e exhibited significant antifungal activity with a minimum inhibitory concentration value of 128 μg mL-1 compared to the standard drug fluconazole (minimum inhibitory concentration, 256 μg mL-1).

Stretchable conducting polymer PEDOT:PSS treated with hard‐cation‐soft‐anion ionic liquid designed from molecular modeling

AbstractPEDOT:PSS, an ionic polymer mixture of positively‐charged poly‐3,4‐ethylenedioxythiophene (PEDOT+) and negatively‐charged poly‐styrenesulfonate (PSS−), is a water‐processable and environmentally‐benign organic semiconductor and electrochemical transistor, which plays a key role in organic (bio)electronic devices. However, pristine PEDOT:PSS films form 10‐to‐30‐nm granular domains, where conducting‐but‐hydrophobic PEDOT‐rich cores are surrounded by hydrophilic‐but‐insulating PSS‐rich shells. Such morphology makes PEDOT:PSS water‐soluble and thermally stable but very poor in conductivity. A tremendous amount of effort has been made to enhance the conductivity of PEDOT:PSS by restoring the extended conduction network of PEDOT. Recently, remarkable ~5000‐fold improvements of conductivity have been achieved by mixing PEDOT:PSS with proper ionic liquids (ILs). In a series of free energy estimations using density functional theory calculation and molecular dynamics simulation, we have demonstrated that the classic hard‐soft acid–base (or cation‐anion) principle of chemistry plays an important role in such improvements. Ion exchange between PEDOT+:PSS− and A+:X− ILs helps PEDOT+ to decouple from PSS− and to grow into large‐scale conducting domains of π‐stacked PEDOT+ decorated by IL anions X−. Thus, the most spontaneous decoupling between soft (hydrophobic) PEDOT+ and hard (hydrophilic) PSS− would be induced by strong interaction with soft anions X− and hard cations A+, respectively. Such hard‐cation‐soft‐anion principles have led us to design ILs containing extremely hydrophilic (i.e., protic) cations and hydrophobic anions. Not only they indeed improve the conductivity of PEDOT:PSS but also enhance its stretchability as well. In summary, our modeling offered molecular‐level insights on the morphological, electrical, and mechanical properties of PEDOT:PSS and a molecular‐interaction‐based enhancement strategy for intrinsically stretchable conductive polymers.

The Effects of Polymerization on the Performance of Viologen-Based Electrochromic Devices.

In this work, electrochromic devices were prepared using the redox couple ethyl viologen diperchlorate and 1,1'-diethyl ferrocene in propylene carbonate as an aprotic solvent to facilitate ions separation and diffusion inside the devices. Electrochromic devices were made using electrochromic gel mixtures at the concentrations of 55%, 60% and 65% with respect to the bisphenol A polymer. In particular, two sets of gels were made: one set contained the bisphenol A not-polymerized while and the second one contained the polymerized polymer. Different techniques, such as cyclic voltammetry, UV-vis-NIR, and Raman spectroscopy, were used to study such systems to understand the differences in terms of performances between the different sets of electrochromic devices. Cyclic voltammetry confirmed that the oxidation process of the 1,1'-diethyl ferrocene and the reduction of the ethyl viologen diperchlorate occurred at about 0.4 V. Interesting variations in the transmittances were found between the two groups of samples. The best values of CE were provided by the electrochromic devices based on the polymerized electrochromic gel mixture at a concentration of 60% (EM60). The EM60 device result was CE = 92.82 C/cm2 in the visible region and CE = 80.38 C/cm2 in the near-infrared region, confirming that these devices can be used for energy-saving applications. A structural characterization of the materials used in the two sets of electrochromic devices was made using Raman spectroscopy, and the analysis supports the electrochemical models used to explain the processes involved during operation of the electrochromic systems.

Towards quantitative microplastic analysis using pyrolysis-gas chromatography coupled with mass spectrometry

Microplastic pollution from everyday plastic items has increased tremendously worldwide. Pyrolysis gas chromatography coupled to mass spectrometry (Py-GC/MS) has been widely investigated for the qualitative and quantitative analysis of microplastics in environmental samples. However, there are several pitfalls to consider when developing an appropriate protocol for their analysis. This study aimed at the development of an in-house database of primary (single) polymers, binary (two) polymers and tertiary (three) polymer mixtures. In this context the potential occurrence of gas phase reactions during pyrolysis of binary and tertiary polymers were investigated. Further, different diluters were tested for the accurate preparation of calibration standards for quantification purposes.Seven different polymers were included in this study, which were chosen due to their prevalence in daily plastic appliances. For each single polymer specific peaks could be identified and recommendation for quantifier analytes given. The analysis of binary polymer mixtures revealed gas phase reactions for PET with PVC, PVC with MDI-PU and PE with PVC. For these binary polymers, several different novel pyrolysis products, specific for the according binary polymer mixture, could be identified. These results confirmed that especially PVC exhibits strong interactions during co-pyrolysis with ester- and ether-based polymers. Similar results were obtained for tertiary polymers.For accurate preparation of calibration standards different diluters (silica, deactivated silica, calcium carbonate, THF and HFIP) were tested. It was observed that deactivated silica had only an influence on the pyrolysis of PET. Whereas, dilution with silica affected PA-6/66, PE, PET and MDI-PU. Only PVC was not influenced by dilution with silica.In conclusion, our results highlight the necessity of an international standard of reference material as well as a standardized analytical protocol for the analysis and quantification of polymers in environmental samples. It is crucial to use diluters suitable for the specific polymer, to exclude potential interactions of diluters with the polymer. The present work has to be seen as a foundation, but future work is needed to adequately address the quantification of polymers in environmental samples.

Thermogravimetric study on thermal degradation kinetics and polymer interactions in mixed thermoplastics

AbstractPotential interactions during thermal degradation of polymer blends significantly influence product yields and their composition. Therefore, chemical recycling of plastic waste requires fundamental understanding of feedstock dependency for effective process design. This study investigates the pyrolysis of polymer blends (HDPE, LDPE, PP, PS, ABS, PET, PA6, PVC) through thermogravimetric experiments at different heating rates. Sample homogeneity’s impact on interactions is analyzed using particles, powder, coextruded blends, and samples in crucibles with separated compartments. A kinetic model is presented to support the experimental findings, assuming linear superposition of individual polymer kinetics. A proposed grouping of thermoplastics, reflecting their degradation behavior and potential interactions, correlates with the polymer structure. Observed interactions, particularly in blends of heteroatom-containing polymers (N, O, Cl), are accelerated reactions and coke formation. Hence, the model accurately predicts the degradation of heteroatom-free polymer mixtures but encounters challenges with more complex blends. This comprehensive study emphasizes the importance of feedstock composition for future pyrolytic polymer recycling. Graphical abstract

Microplastics impair extracellular enzymatic activities and organic matter cycling in oligotrophic sandy marine sediments

Microplastics (MPs) are ubiquitous and constantly accumulating in the marine environment, especially sediments. Yet, it is not well clarified if and how their carbon backbone could interact with surrounding sediments, eventually impairing key benthic processes. We assessed the effects of a ‘pulse’ contamination event of MPs on sedimentary organic matter (OM) quantity, quality and extracellular enzymatic activities (EEAs), which are well established descriptors of benthic ecosystem functioning. Marine sediments were exposed for 30 days to environmentally relevant concentrations (∼0.2 % in weight) of naturally weathered particles (size range 70–210 μm) of polyurethane, polyethylene, and a mixture of the most common polymers that are documented to accumulate in marine sediments. Despite the low concentration, contaminated sediments showed significantly different composition of OM, showing a decrease in lipid content and increase in protein. Moreover, we document a significant decrease (over 25 %) in quantity of biopolymeric C already after 15 days of exposure, compared to controls. Contaminated sediments showed lower C degradation rates (up to −40 %) and altered EEAs, with alkaline phosphatase being ∼50 % enhanced and aminopeptidase being reduced over 35 % compared to control treatments. Overall, the effects generated by the mixture of polymers were smaller than those exerted by the same amount of a single polymer. Our results provide insights on how that MPs can significantly alter marine sedimentary biogeochemistry through altered benthic processes, that could cumulatively impair whole benthic trophic webs by enhancing the accumulation and possible longer-term storage of recalcitrant organic C in the seabed.

Diffusion and Exchange Kinetics of Microparticle Formulations by Spatial Fourier Transform Fluorescence Recovery after Photobleaching with Patterned Illumination.

The mechanism of active pharmaceutical ingredient (API) mobility during release in microparticle formulation was investigated using periodically structured illumination combined with spatial Fourier transform fluorescence recovery after photobleaching (FT-FRAP). FT-FRAP applies structured photobleaching across a given field of view, allowing for the monitoring of molecular mobility through the analysis of recovery patterns in the FT domain. Encoding molecular mobility in the FT domain offers several advantages, including improved signal-to-noise ratio, simplified mathematical calculations, reduced sampling requirements, compatibility with multiphoton microscopy for imaging API molecules within the formulations, and the ability to distinguish between exchange and diffusion processes. To prepare microparticles for FT-FRAP analysis, a homogeneous mixture of dipyridamole and pH-independent methyl methacrylate polymer (Eudragit RS and RL) was processed using laminar jet breakup induced by vibration in a frequency-driven encapsulator. The encapsulated microparticles were characterized based on particle size distribution, encapsulation efficiency, batch size, and morphology. Utilizing FT-FRAP, the internal diffusion and exchange molecular mobility within RL and RS microparticles were discriminated and quantified. Theoretical modeling of exchange- and diffusion-controlled release revealed that both RL and RS microparticles exhibited similar exchange decay rates, but RL displayed a significantly higher diffusion coefficient. This difference in diffusion within RL and RS microparticles was correlated with their macroscopic dissolution performance.

Co-sorption of volatile components in polymer-based pharmaceutical formulations

Amorphous Solid Dispersions (ASDs) are mixtures of active pharmaceutical ingredients (APIs) and polymers aiming to increase API aqueous solubility and bioavailability. ASDs are often produced using solvent-based manufacturing, such as spray drying. Due to solubility or miscibility limitations in one solvent, solvent mixtures are frequently used for this purpose. Drying solvents or solvent mixtures from polymer-based products like ASDs is an energy-intensive and time-consuming process. Designing and optimising this drying process requires knowledge of the sorption isotherms of the solvent(s) in these polymer-based products. In this work, we developed a novel approach for measuring the simultaneous absorption/desorption of two solvents in a polymer. Combining classical dynamic vapour sorption (DVS) measurements with Raman spectroscopy, this innovative approach provides a more detailed and accurate measurement of the sorption isotherms than common methods. Moreover, we developed an approach for precisely predicting the sorption equilibria in three-component systems just based on sorption data of the corresponding binary subsystems. Our modelling approach combines the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) with the Non-Equilibrium Thermodynamics of Glassy Polymers (NET-GP). Building on the description of the sorption isotherms of either water or ethanol in poly(vinylpyrrolidone-co-vinyl acetate) (PVPVA64) and in indomethacin (IND), we were able to quantitatively predict the simultaneous sorption of water and ethanol in PVPVA64 and the one of ethanol in an IND/PVPVA64 ASD.

Numerical simulations of polymer devolatilization in a steam contactor: Correlating particle distribution with volatile content removal

Abstract The focus of the current study is on a polymer devolatilization process in a device called a contactor, that involves the use of superheated steam to eliminate volatile cyclohexane, through evaporation, from the polymer mixture, also known as cement. The primary objective is to analyze the cement particle distribution and how it relates to the cyclohexane content at the exit or the devolatilization efficiency. The study develops a computational fluid dynamics (CFD) model that solves for the turbulent steam flow as a continuous phase and the the flow of cement droplets as a discrete phase. Following validation of the CFD model by comparing cement particle size distribution at the exit of the contactor to experimental data, a detailed examination of the same is conducted through a series of 69 CFD different calculations to understand its influence on the evaporation of the volatile in the polymer mixture. Two metrics are developed here: a cluster distribution index (CDI) based on the actual particle pairwise distances and a new mass-CDI based on the the radial distribution of masses. It is demonstrated that by relating the CDI and mass-CDI to the reduction in the cyclohexane content in the contactor, these metrics can be utilized to achieve the desirable input conditions in this polymer processing operation. Through a detailed examination of the particle dynamics in a steam contactor under various conditions, this study assists the polymer manufacturing industry in optimizing the devolatilization process for better steam savings and improved product quality.

Co-delivery of novel valsartan and hydrochlorothiazide pH-responsive electrospun polymeric nanofibers for improved oral delivery

Valsartan (VAL) and Hydrochlorothiazide (HCTZ) as a fixed-dose combination are widely used for the management of hypertension. To enhance the dissolution and oral delivery of VAL (BCS class II drug) and HCTZ (BCS class IV drug), nanofibers containing both drugs were prepared using an electrospinning technique. VAL/HCTZ-loaded NFs were prepared using Eudragit L100-55 (EUD L100-55) and Poly (ethyne oxide) (PEO) polymer mixture and the formulation process was optimized through three process variables of polymer composition, polymer concentration, and spinning voltage. VAL/HCTZ-loaded NFs were characterized for their size, surface morphology, entrapment efficiency (%EE), drug-polymer interaction, in vitro drug release, ex-vivo permeation, and in vivo studies. Smooth, beadles and uniform drug-loaded NFs were successfully fabricated using optimum polymer composition (EUD L100-55/PEO 3:1), concentration (12 % w/v), and applied voltage (30 KV). The optimum formula (F9) showed a low average nanosize of 300 nm and a high drug loading of > 90 % was achieved. In vitro, release results showed a pH-dependent drug release, with minimum drug released at pH lower than 4.5, but a significant and complete release of both drugs was achieved at pH 6.5. The EUD L100-55/PEO improved the dissolution of VAL and HCTZ compared to free drugs at the intestinal site of absorption. Differential Scanning calorimetry and Fourier Transform Infra-Red studies showed both drugs’ amorphization and compatibility between drugs and polymers. Permeability behavior for the VAL/HCTZ-loaded NFs was found to be significantly higher than free drug suspensions of both drugs which indicated the improvement of VAL and HCTZ permeability through the intestinal membrane. The in vivo study proved the enhanced oral anti-hypertensive action of drugs-loaded NFs compared to free drug suspensions. The superior in vitro release, ex-vivo permeation, and in vivo anti-hypertensive effect indicate that drug-loaded nanofibers have the potential to improve the biological activity and hence oral delivery of the fixed-drug combination.

Improving The Geotechnical Properties of Cohesive Soils Using Portland Cement and Some Composite Polymers in A Selected Location in The City of Tanumah / Basrah Governorate – Southern Iraq

Background: The purpose of this research is to ascertain how adding Portland cement and composite polymers, as well as the ideal ratios between them, will affect cohesive soils' geotechnical characteristics. Materials and Methods: A composite polymer was created by combining three polymers—isocyanide, unsaturated polyester, polyvinyl acetate, and thinner—as well as a solvent. Portland cement was added to the soil at a rate of 5% of the sample weight. Different percentages of the weight of the cement supplied to the sample—5, 10, 15, 20, and 25%—were utilized as the composite polymer. Several geotechnical tests were carried out, including compaction, unconfined compressive strength, California bearing ratio, absorption, and Atterberg's limits, to ascertain the ideal amount of polymer for the aim of improvement. Results: The findings show that adding cement at a rate of 5% by weight of the sample and a polymeric mixture at a rate of 15% by weight of cement can improve the cohesive soil's engineering properties. It was found that the maximum dry density, unconfined compressive strength, and California bearing ratio had increased while the values of the optimal moisture content, absorption rate, liquid limit values, and plasticity index had decreased. Conclusion: The composite polymer used in soil improvement not only improves the geotechnical properties and resistance of the soil, but it also efficiently enhances and activates the effectiveness of cement. When 15% of the sample's weight of cement was composed of composite polymers, the soil's engineering attributes increased the most.

Nanoencapsulation of citrus essential oils in systematic modified chitosan‐based nanofibers

AbstractIn this study, chitosan (CH)/polyvinyl alcohol (PVA) hybrid nanofibers incorporating three distinct essential oils lemon, lime, and grapefruit were successfully obtained via the innovative electrospinning technique. Characteristics of the electrospinning polymeric mixture loaded with essential oils using variable ratios of CH/PVA were evaluated. The nanoencapsulation process of citrus essential oils was achieved with 47.67%–88.16% encapsulation efficiency. Notably, the thermal stability of the encapsulated essential oils experienced a significant enhancement after encapsulation. Scanning electron microscopy analysis revealed valuable insights, revealing that an increased amount of incorporated essential oil within the polymeric mixture solutions led to a reduction in the average fiber diameters. The resulting nanofibers demonstrated notable attributes such as antioxidant, tyrosinase inhibitory, and antibacterial activities. The present research demonstrates the ability of CH/PVA hybrid nanofibers obtained through an electrospinning process to preserve citrus essential oils properties quality and reveals a high potential application of nonencapsulated citrus essential oils in biomaterials, food packaging, and advanced cosmetic application.

Microplastic and Associated Black Particles From Road‐Tire Wear: Implications for Radiative Effects Across the Cryosphere and in the Atmosphere

AbstractThe environmental effects of airborne micro‐ and nano‐size plastic particles are poorly understood. Microscopy and chemical analyses of atmospherically deposited particles on snow surfaces at high elevation (2,865–3,690 m) in the Upper Colorado River basin (UCRB; Colorado Rocky Mountains) revealed the presence of black substances intimately associated with microplastic fibers, particles interpreted to have originated as tire matter. Identical and similar particles occur in shredded tires and road‐surface samples. The substance responsible for the black color of all tires is carbon black, a graphitic light‐absorbing tire additive produced by hydrocarbon combustion that homogeneously permeates the mixture of tire polymers and other additives. Such black tire matter may thus exert radiative effects closely similar to those of black carbon. The presence in snow of many organic compound types common to tires, measured by two‐dimensional gas chromatography, suggests that atmospherically deposited black road‐tire‐wear matter is among the light‐absorbing particulates that advance the onset and rate of snow melt in the UCRB. The mass of road‐tire‐wear particles shed from vehicles may be estimated by multiplying measured amounts of eroded tire‐per‐distance traveled by vehicular distances. Under a combination of measurements and assumptions about the amounts and radiative properties of atmospheric tire‐wear particles, the radiative effects of these particles might add about 10%–30% to those effects from black carbon, an estimate ripe for revision. On regional and global scales, the amounts and effects of emitted and deposited tire‐wear matter likely vary by factors of geographic source, transport pathway, and depositional setting.

Synthesis and Characterization of Shungite Modified Poly-N-Ninylpyrrolidone-Agarose Composites for Medical Application.

A systematic investigation was conducted to synthesize hybrid composite materials that use synthetic poly-N-vinylpyrrolidone and natural (agar-agar) macromolecules with plasticizers (PEG-400) and mineral filler shungite by means of electron irradiation. The XRD and SEM data showed that the structure of the resulting hybrid composites is an interpenetrating network with distributed particles of mineral component. It has been established that the mechanical properties of hybrid composites are determined mainly by the structural organization of the interpenetrating polymer network formed under electron irradiation of the initial synthetic and natural polymer mixture in the presence of plasticizers, as well as by the conditions for intercalation of polymer segments into the mineral matrix and vice versa. It has been revealed that the degree of swelling of hybrid composites strongly depends on the concentration of a low-molecular plasticizer in the polymeric interpenetrating network, which easily impregnates into the matrix of shungite. Successfully obtained [PVP-AA-PEG] hydrogels with shungite can be applied in regenerative medicine as wound healing dressings.

Environmentally friendly molecularly imprinted polymers as an insert for SPE type columns in the gentamicin monitoring process

The quantity and variety of micro-pollutants infiltrating water resources have increased rapidly in recent times. The appearance of many harmful substances in the waters has resulted in so-called chemical cocktails which significantly contribute to the deterioration of water quality. Additionally, the variety of these compounds, often similar to each other in terms of molecular weights, makes their separation and identification very difficult. In this paper we present the possibility of using self-regenerating mechanism of molecularly imprinted polymers to measure the concentration of micropollutants in the aquatic environment. Molecularly imprinted polymers toward gentamicin were prepared by monomer polymerization in aqueous solution at ambient temperature. Results from computer-based molecular modelling demonstrated potential binding sites between gentamicin and functional monomers in water. Various compositions of polymerization mixtures were tested. The ratio of monomers to each other was 1.1:1.4:0.0015 and 1:1:1 for N-isopropylacrylamine:acrylamide:acrylic acid, respectively. For each composition, various amounts of the standard were tested: 0, 3, 5, 7, 10,15 mol% in relation to monomers. The best results were obtained for 5 % gentamicin with an excess of acrylamide in relation to the other monomers. Sorption for this system was 0.783 mg/g at ambient temperature and desorption 0.593 at 4 °C. The synthesized materials, thanks to the incorporation of thermosensitive poly(N-isopropylacrylamide) into their structures, were able to release 89 % of adsorbed gentamicin. This made it possible to use the designed SPE columns repeatably with similar efficiency. The prepared materials were selective in the presence of other antibiotics like amoxicillin and norfloxacin.

In-vivo Evaluation Methods for Preparation of Ophthalmic In-situ Gel

The eye is a vital component of the human sensory system, but various things can pose a threat to its cleanliness and well-being. An in-situ ophthalmic gel is one of the preparations developed to optimize the pharmacological activity in the eye. This formulation is intended to extend the drug's duration in the eye. An assessment is necessary to guarantee its occurrence and mitigate any adverse repercussions. The literature search conducted in this evaluation focused on an in-vivo study, enabling the collection of various pharmacokinetic data, including Cmax, Tmax, area under curve (AUC), and mean residence time (MRT). The polymer is an essential element in this inquiry, so the selection must be accurate according to the results of the literature review. The most effective method is high-performance liquid chromatography (HPLC), and the most effective polymer is a composite polymer formed by combining different types of polymers, such as Pluronic F127 and carbopol, pectin and thiolate, poloxamer and carbopol, and gellan gum and hydroxyethylcellulose. Aside from the polymer mixture, the poloxamer solution has the potential to produce highly positive results.

Kinetics of Low Molecular Substances Sorption by the Polymer Mixtures

The sorption capacity of polymer blends was analyzed on the basis of absorption kinetics. The study was carried out in an adsorption-active medium with different degrees of deformation. Heptane and butanol were used as adsorption-active media. The influence of the chemical nature of the adsorbate on the sorption process was studied. The free volume fractions for each sample of the composition were calculated. The ability of materials to absorb different amounts of substances allows us to identify the behavior peculiarities of the interfacial regions of different chemical compositions.

Design and Optimization of Solid Lipid Nanoparticles for Enhanced Therapeutic Activity of Linagliptin.

To augment oral bioavailability, linagliptin (LGP) loaded solid lipid nanoparticles (SLNs) have been formed using the solvent evaporation technique of emulsification. Utilizing the Box Behken design (BBD), examining the relation between independent and dependent variables was possible. Particle size (PS), entrapment efficiency (EE), and in-vitro drug release (DR) studies were considered response factors, whereas the various concentrations of lipid carrier, surfactant, and co-surfactant were considered process variables for optimization. The design expert program was used to obtain the optimized batch. At 24 hours, it was discovered that the optimized batch expected responses for PS, %EE, and %DR were 105.83 nm, 81.19, and 96.69%, respectively. The observed PS, %EE, and %DR responses of the optimized batch at 24 hours were determined to be 101.36 nm, 80.56, and 96.31%, respectively. There is no interaction seen in the basic physical mixing of drug and polymer, according to the FTIR spectra of pure drugs, polymers, and drug and polymer mixtures. The optimized formulation’s average size was found to be 138 nm by the particle size analysis. Similarly, a value of 0.255 was found by the polydispersity index (PDI). This suggests that the SLN in the formulation has a homogeneous size dispersion. With a zeta value of -32.8 mV, stability is indicated. Linagliptin was effectively developed as a drug with a 24-hour sustained release. Wistar rats were used in the in-vivo evaluation of linagliptin SLN formulations. The drug bioavailability increased five times (a highly significant fivefold increase) in LGP-loaded SLNs (AUC0-t ≈ 134.5 μg*h/mL) compared to raw LGP (AUC0-t = 27.23 μg*h/mL).