Polimery w medycynie最新文献

Several factors, including characteristic polymer composition of the cell wall, based on peptidoglycans cross-linked with arabinogalactans, together with the lipid layer contribute to the high resistance of Mycobacterium tuberculosis to antibiotics and other anti-tuberculosis drugs, leading to the development of new treatment methods. Implementation of therapeutic drug monitoring for anti-mycobacterial drugs in routine clinical practice requires understanding of the limited stability of these drugs. Rifampicin and isoniazid are the main anti-tuberculosis drugs that generate degradation products during sample handling and storage. Therefore, analytical methods used for analysis of clinical samples collected from tuberculosis patients treated with a combination of different drugs should enable the separation of the studied analytes from their metabolites and degradation products. Moreover, the samples require strictly regulated collection and storage conditions to prevent degradation processes. The purpose of this review was to present recent data on the stability studies of anti-mycobacterial drugs, specifically used as first-line treatment in patients with tuberculosis. Detailed degradation pathway of rifampicin was described, including conditions influencing the formation of specific rifampicin related substances. Moreover, the results of the stability studies of anti-mycobacterial drugs were presented in various matrices in conditions determined by international guidance such as U.S. Food and Drug Administration (FDA) or International Council for Harmonisation (ICH) guidelines. Particular attention was given to analytical methods designed for analysis of anti-mycobacterial drugs in the presence of their degradation products. Finally, recommendations proposed by different authors for collection, processing and storage of clinical samples to increase stability of anti-mycobacterial drugs were summarized.

Background: Poly(glycerol sebacate) is a polymeric material with potential biomedical application in the field of tissue engineering. In order to act as a biodegradable scaffold, its incubation study is vital to simulate its behavior.

Objectives: This study explores the degradation of porous poly(glycerol sebacate)/hydroxyapatite scaffolds subjected to incubation in various physiological solutions.

Material and methods: The research involved monitoring pH and conductivity values over a 14-day period, as well as analyzing the swelling capacity and mass alterations of the scaffolds.

Results: In simulated body fluid (SBF) and phosphate-buffered saline (PBS), the pH levels remained relatively stable, whereas Ringer's solution caused a pH decrease. Conversely, artificial saliva demonstrated an increase in pH, and distilled water caused a slight decrease. The conductivity values remained stable in SBF and Ringer's solution, slightly decreased in PBS, increased in artificial saliva, and significantly increased in distilled water. The swelling capacity of the scaffolds varied depending on the solution used, with the lowest equilibrium swelling observed in SBF and PBS. The effect of the presence of ceramics on this parameter was also observed. The mass changes of the scaffolds indicated deposition of particles or salts from the incubation solutions, and subsequent rinsing in distilled water led to a decrease in mass. Scanning electron microscopy (SEM) imaging and elemental analysis confirmed the presence of crystallized salts on the scaffold surfaces after incubation in SBF. Surface roughness measurements revealed changes in roughness depending on the solution, with deposition of additional layers in SBF and degradation in artificial saliva.

Conclusions: In summary, the scaffolds exhibited biodegradation in physiological solutions, with variations in pH, conductivity, swelling capacity, mass changes, and surface morphology depending on the specific solution and scaffold composition.

The spinal cord is one of the most important part of the human nervous system and great importance is placed on developing the best treatment for its damage. 3D bio-printing technology, and the fabrication of special scaffolds using it, is a potential solution for regenerating damage in spinal cord injuries (SCIs). Bio-printing can be divided into indirect and direct bio-printing, while among the bio-printing methods, inkjet bio-printing, fused deposition modeling (FDM), extrusion bio-printing, or light-assisted bio-printing can be distinguished. The last group can be in turn divided into several separate techniques such as digital light processing (DLP), stereolithography (SLA) and laser-assisted bio-printing (LAB). While bio-printing technology for the treatment of SCI is in the early stages of research, several successful trials have already been performed, where the use of such scaffolds has resulted in at least partial restoration of autonomic nervous system function in patients with chronic and acute SCI.

Background: The drug interactions with the lipid membranes are crucial in many biochemical processes. Phospholipid model membranes are often used to assess such interactions. Our team has been researching new compounds with anti-inflammatory and analgesic effects for many years. Such compounds are derivatives of the well-known non-steroidal anti-inflammatory drug (NSAID) - meloxicam (MLX). Their biological target is cyclooxygenase (COX) - a membrane protein. The NSAIDs are mainly taken orally; therefore, drug-membrane interaction is a preliminary stage in the body.

Objectives: The purpose of the present work was to investigate the ability of 2 new MLX derivatives (compound PR51 and PR52) to interact with model membranes, in comparison to known NSAIDs medicine - MLX. The differential scanning calorimetry (DSC) method was used to study those interactions. As a model membrane, bilayers obtained from a phospholipid (1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC)) were used.

Material and methods: Calorimetric measurements were performed using a differential scanning calorimeter DSC 214 Polyma equipped with an intracooler IC70.

Results: All examined compounds decreased the main transition temperature of DPPC in a concentration-dependent manner. The addition of studied compounds to DPPC also resulted in broadening of the transition peaks. Moreover, all examined compounds decreased the enthalpy of the DPPC main phase transition. For all DPPC gel-liquid crystalline phase transition parameters, the most pronounced effects were found for PR51 compound.

Conclusion: We have shown that the above interactions depend on the chemical structure of individual compound. All studied compounds alter biophysical properties of phospholipid bilayer.

Microencapsulation is a technology for encapsulating particles in a coating designed to isolate the core substance from external conditions, including oxidation, UV radiation or humidity. Microcapsules reach dimensions of up to 5,000 μm. In the pharmaceutical industry, they are used for the controlled release of active substances, masking their taste, odor or gastrointestinal irritation, and can also reduce the toxicity of some medicinal substances. In the food production industry, the encapsulation process applies to sweeteners, enzymes, microorganisms, vitamins and minerals, flavors, or colors. The production of microcapsules is based on the use of their physical properties such as amphiphilicity, partition coefficient and melting point, while their formation of microcapsules is mainly carried out using physical methods such as coacervation, spray drying, cooling and coating, agglomeration, suspension crosslinking, solvent evaporation, and extrusion, as well as chemical methods: interfacial polymerization and in situ polymerization. Although traditional methods are still used to produce microcapsules, contemporary methods employing the latest technology are also emerging. One such method is encapsulation in microcylinders produced with a 3D printer.

Background: Hydrogels, containing a large amount of water and exhibiting high biocompatibility, can improve the rheological properties of formulations and adhere well to the application site. In Poland, only 1 hydrogel substrate is currently approved for pharmaceutical compounding: Celugel, based on hydroxyethyl cellulose (HEC).

Objectives: The aim of this study was to investigate how the variation in the raw material composition of Celugel-based hydrogels affects their osmotic pressure values and selected rheological properties.

Material and methods: Ten gel formulations were prepared using a commercial Celugel as the base, with varying percentages of added water, alongside a consistent 5 wt% addition of sucrose. The research methods employed include osmotic pressure, dynamic viscosity, pH measurement, and surface tension using the du Noüy ring tensiometer.

Results: The composition of the formulation has a significant impact on the osmotic pressure. Nearly all of the hydrogels exhibited hyperosmotic characteristics relative to living tissues, with measured osmotic pressure values ranging from 160 mOsm/kg H2O to 1,480 mOsm/kg H2O. As anticipated, the viscosity of the formulations increased proportionally with the growing concentration of Celugel ranging from 2.19 mPa·s to 562.87 mPa·s.

Conclusion: The composition of Celugel significantly influences its rheological properties and osmotic pressure values, with the concentration of the gelling agent being the most impactful factor. The results suggest that Celugel is suitable for use in formulations intended for nasal administration.

Background: One of the key challenges in tissue engineering area is the creation of biocompatible scaffolds that support cell growth and mimic the structural and mechanical properties of native tissues. Among various materials used for scaffold fabrication, composite materials based on biodegradable polymers reinforced with bioactive inorganic fillers have attracted significant attention due to their properties. One of the important problems with the preparation of composite electrospun fibers is the low filler content in the fiber.

Objectives: This study aims to select the best composition for electrospun polymer fibers in terms of potential application in tissue engineering. The effect of the viscosity of polymer solution/dispersion and filler content on the structure and properties of the fibers was determined. Morphology and filler content were compared.

Material and methods: Series of electrospun composite fibers were fabricated from poly(ĺ-caprolactone) (PCL), poly(L-lactic acid) (PLLA) and hydroxyapatite (HAP), containing from 10 wt% to 40 wt% HAP. The properties of the resulting composites were studied using scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and viscosimetry measurements.

Results: The addition of HAP to the polymer solution caused a significant increase in viscosity, but the results showed that it is possible to obtain composite electrospun fibers even with 40 wt% filler content. Scanning electron microscopy analysis shows randomly oriented electrospun fibers with an average diameter in the range of 3.8-8.5 ěm for solution and dispersion with high viscosity (1,210-2,000 mPa·s) and significantly larger diameters (approx. 12 ěm) for the PCL solution (326 mPa·s).

Conclusion: It is possible to transform the composite dispersion from biopolymers and HAP into nonwoven fabrics at up to 40 wt% filler content. Due to their unique properties, such materials are promising for application in tissue engineering.

Globally, skin cancer is the predominant form of cancer, with melanoma identified as its most deadly variant. Projections suggest a surge exceeding 50% in melanoma occurrences by 2040, underscoring the urgency for preventive interventions. Sulforaphane (SFN), a compound found in cruciferous vegetables, is recognized for its cancer-preventive capabilities, particularly against skin cancer. This study employed a rigorous systematic review of various databases, adhering to predefined inclusion criteria for study selection. Data extraction was conducted using a uniform template, and the quality of the included studies was evaluated through the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) risk of bias tool, specifically designed for animal research. The review encompasses studies published in English from 2000 to 2023, culminating in the inclusion of 9 pertinent studies. The findings highlight SFN's capacity to act as a protective agent in preventing skin cancer in animal models. It demonstrated efficacy in curbing skin tumorigenesis triggered by assorted carcinogens, reducing the onset of skin tumors and impeding the growth and spread of skin cancer cells. Furthermore, SFN showed preventive effects against UVB-induced skin carcinogenesis by obstructing the activator protein 1 signaling pathway. Based on evidence from animal-based research, SFN emerges as a promising chemopreventive substance against skin cancer. Nevertheless, determining its optimal dosage, application duration and method of administration for human subjects remains pending. If its effectiveness is substantiated, SFN could complement or offer an alternative to existing preventive measures against skin cancer.

Background: Acne vulgaris is a common inflammatory skin condition affecting almost 85% of the adolescent and young adult population. The etiopathogenesis of this dermatosis involves an imbalance in the skin microbiome, leading to inflammation of both the skin and hair follicles.

Objectives: The aim of this study was to develop topical anti-acne formulations with increased therapeutic efficacy and reduced risk of developing antibiotic resistance. Six hydrogel formulations containing azelaic acid or its derivative, azeloglycine, in combination with tetracycline hydrochloride were prepared as part of the study.

Material and methods: The investigated formulations were prepared using an Eprus U500 pharmaceutical mixer and the pH was determined using an ERH-11S electrode designed for dense substances and a CPC-505 Elmetron pH-meter. The formulations were analyzed for tetracycline stability in the presence of additional active ingredients and varying pH over a period of 35 days using high-performance liquid chromatography (HPLC). In addition, the effects of azeloglycine and azelaic acid on the viscosity of the prepared formulations were evaluated using a Brookfield DV2T rotational viscometer.

Results: Chromatographic analysis showed significant stability of tetracycline in most formulations, with azeloglycine-containing formulations showing less degradation of the antibiotic than azelaic acid-containing preparations. In addition, azeloglycine-containing gels exhibited more favorable rheological properties, which may facilitate better application and be more beneficial to patients.

Conclusion: The results suggest that formulations containing azeloglycine and tetracycline may be a promising strategy for acne therapy, offering increased tetracycline stability and an optimal rheological profile, which may result in prolonged therapeutic effect and more effective drug delivery to the skin.

Developing the analytical procedure requires estimating what independent variables will be tested and at what levels. There are statistical models that enable the optimization of the process. They involve statistical analysis, which indicates the crucial factors for the process and the potential interactions between the analyzed variables. Analysis of variance (ANOVA) is applied in the evaluation of the significance of the independent variables and their interactions. The most commonly used chemometric models are Box-Behnken Design, Central Composite Design and Doehlert Design, which are second-order fractional models. The alternative may be the artificial neural networks (ANN), whose structure is based on the connection of neurons in the human brain. They consist of the input, hidden and output layer. In such analysis, the activation functions must be defined. Both approaches might be useful in planning the analytical procedure, as well as in predicting the response prior to performance the measurements. The proposed procedures may be applied for polymeric systems.