Polimery w medycynie最新文献

In recent years, there has been a great interest in the potential use of contact lenses as eye drug delivery systems. Static (individual layers of the cornea, sclera and retina) as well as dynamic barriers (blood flow) pose a serious challenge to the effective delivery of the drug substance to the eyeball. The current ophthalmic systems are not optimal for patients, especially in the form of eye drops, where almost 95% of the drug contained in them is lost through the process of absorption through the conjunctiva or tear drainage. This article describes in vitro experiments that examined the use of contact lenses in the context of drug treatment in infectious, inflammatory, allergic, and glaucomatous diseases. Various techniques used to modify the materials as well as their impact on drug release kinetics were discussed. It has also been demonstrated that these methods can be used in practice during in vivo research, both in animal models as well as in sick and healthy people. The advantages of using controlled-release drug systems in the form of contact lenses are the drug dosing regimen, bioavailability and the prolonged residence time of drugs in the eyeball.

Background: Sida cordifolia and Sida rhombifolia are regarded as useful herbs as they have been shown to be effective, inexpensive and harmless in the prevention of diabetes, and are recognized as valuable therapeutic substances.

Objectives: The purpose of this study was to assess the effect of S. cordifolia and S. rhombifolia in the treatment of diabetic nephropathy using a rat model.

Material and methods: Extracts of S. cordifolia and S. rhombifolia were obtained using the Soxhlet method. The hydroalcoholic extract solvent was used in the following proportions: 70:30, 50:50 and 80:20. The 80:20 hydroalcoholic extract was observed to be the most potent. The inhibitory effects of the extract were determined using the α-amylase assay. The most potent extract also underwent total flavonoid, phenolic and free radical scavenging tests, and was incorporated into an animal study. Diabetes was induced in rats by administering nicotinamide (NAD; 230 mg/kg) and streptozotocin (STZ; 65 mg/kg) intraperitoneally. In addition to a standard control of pioglitazone, the rats received extract dosages of 100 mg/kg/day or 200 mg/kg/day. Body weight, blood glucose, glycated hemoglobin (HbA1c), blood urea nitrogen (BUN), serum albumin, serum creatinine, homeostatic model assessment of insulin resistance (HOMA-IR), and oral glucose tolerance were assessed at various time points. The animals also underwent histopathological examination to observe alterations induced by the treatment.

Results: Sida cordifolia was the most successful in lowering blood glucose and HbA1c levels. Renal function indices and antioxidant enzyme levels were regained in a dose-dependent manner. Furthermore, S. cordifolia (200 mg/kg/day) extract, similar to pioglitazone, inhibited the production of advanced glycation byproducts by the kidney.

Conclusions: The effects of various S. cordifolia and S. rhombifolia extracts on rats with diabetic nephropathy were observed. Sida cordifolia may be further explored for the treatment of diabetic nephropathy and, due to its diverse nature, may be utilized for the treatment of a wide range of diseases, as it provided more significant findings.

Background: Polymethylmethacrylate (PMMA) is the most used material for the manufacturing of eye prostheses.

Objectives: To investigate the cytotoxicity of different cleaning agents for ocular prostheses on human conjunctival cells.

Material and methods: Six groups of specimens were created (saline, soap, 4% chlorhexidine, hydrogen peroxide, 1% triclosan, and citronella oil). Three specimens were made for each disinfectant at each disinfection period (1, 7, 15, 30, 60, and 90 days), totaling 108 specimens. Thus, the specimens were disinfected, with different disinfectants, for different periods of time. After each disinfection process, the specimens were washed with sterile distilled water. A human conjunctival cell line was grown on the acrylic resin specimens and then cytotoxicity tests (MTT and Neutral Red (NR)) were performed. A negative control (untreated cell cultures) and positive control (Tween 20) were created. Two-way analysis of variance (ANOVA) and Bonferroni test were performed (p < 0.05).

Results: For the MTT and NR tests, when there was a significant difference between the disinfectant and negative control, the disinfectant generated a significant reduction in cell proliferation most of the time.

Conclusions: All reductions in cell proliferation caused by the disinfectants were clinically acceptable. All disinfectants tested in this study were found to be non-cytotoxic to human conjunctival cells.

Hepatocellular carcinoma (HCC) is the 7th most common cancer and the 3rd leading cause of cancer-related death worldwide. It is resistant to the majority of chemotherapeutics and has a dismal prognosis. Hepatocellular carcinoma is a prevalent complication of chronic liver disease (CLD) in India. Primary liver cancer is the 6th most common cancer worldwide and the 4th most prevalent cause of cancer-related death. In 2018, it affected 841,000 people and caused 782,000 deaths around the world. Thus, research into the tumor cycle and its prevention through suitable herbal (Unani/Ayurvedic) medication is critical for reducing the impact of primary liver cancer. Treatment options for end-stage liver cancer are limited, necessitating costly liver transplantation, which is unavailable in most countries. Here, we present the results of a comprehensive literature survey to determine the benefits of using various herbs with liver protective and antioxidant properties. This information will be useful to researchers working on liver carcinoma and free radical scavenging, both of which are important in curbing potential carcinogens.

Background: A basic parameter in non-equilibrium thermodynamics is the production of entropy (S-entropy), which is a consequence of the irreversible processes of mass, charge, energy, and momentum transport in various systems. The product of S-entropy production and absolute temperature (T) is called the dissipation function and is a measure of energy dissipation in non-equilibrium processes.

Objectives: This study aimed to estimate energy conversion in membrane transport processes of homogeneous non-electrolyte solutions. The stimulus version of the R, L, H, and P equations for the intensity of the entropy source achieved this purpose.

Material and methods: The transport parameters for aqueous glucose solutions through Nephrophan® and Ultra-Flo 145 dialyser® synthetic polymer biomembranes were experimentally determined. Kedem-Katchalsky-Peusner (KKP) formalism was used for binary solutions of non-electrolytes, with Peusner coefficients introduced.

Results: The R, L, H, and P versions of the equations for the S-energy dissipation were derived for the membrane systems based on the linear non-equilibrium Onsager and Peusner network thermodynamics. Using the equations for the S-energy and the energy conversion efficiency factor, equations for F-energy and U-energy were derived. The S-energy, F-energy and U-energy were calculated as functions of osmotic pressure difference using the equations obtained and presented as suitable graphs.

Conclusions: The R, L, H, and P versions of the equations describing the dissipation function had the form of second-degree equations. Meanwhile, the S-energy characteristics had the form of second-degree curves located in the 1st and 2nd quadrants of the coordinate system. These findings indicate that the R, L, H, and P versions of S-energy, F-energy and U-energy are not equivalent for the Nephrophan® and Ultra-Flo 145 dialyser® membranes.

Background: Occlusal splints can protect teeth during bruxism, preventing tooth wear, as well as during sports activities, shielding them from impacts.

Objectives: To verify the influence of thermal cycles and disinfection on the roughness, microhardness and color of polyethylene terephthalate glycol/thermoplastic polyurethane (PETG/TPU) and poly(methyl methacrylate) (PMMA).

Material and methods: Thirty-six PETG/TPU samples and 36 PMMA samples were prepared (ø10 mm × 3 mm). Six groups were created according to the material and the disinfection method used (n = 12 each): PETG/TPU (glister), PETG/TPU (hypochlorite), PETG/TPU (soap), PMMA (glister), PMMA (hypochlorite), and PMMA (soap). Roughness, Knoop microhardness and color evaluations were performed before the experiments (T1), after thermocycling (T2) and after disinfection (T3). Three-way repeated measures analysis of variance (ANOVA) and Tukey's test were used for statistical evaluations.

Results: For roughness and color, ANOVA showed statistical significance based on the interaction between thermal cycling, material and disinfectant factors. In terms of Knoop microhardness, ANOVA showed statistical significance based on the interaction between thermal cycling and material factors.

Conclusions: Roughness results were clinically acceptable in all groups at all time points, except the PETG/TPU and PMMA groups disinfected with hypochlorite. Microhardness significantly increased for both materials after thermal cycling, and at all time points, the microhardness of PMMA was significantly higher than that of PETG/TPU. After thermal cycling, the color changes were clinically unacceptable in all groups.

The available information on the abundance of restorative plants on earth is incomplete, and the data regarding botanicals from various countries differ significantly. The substantial development of the worldwide natural botanical market is attributable to the expanding revenue of global drug companies trading herbal medicines. This essential type of traditional medical care is depended on by approx. 72-80% of individuals. Even though numerous restorative plants are readily used, they have never been subject to the same strict quality guidelines as conventional drugs. Nonetheless, it is vital to have specific organic, phytochemical, and molecular tools and methods for identifying restorative plant species so that traditional and novel plant products can be safely used in modern medicine. Molecular biotechnology approaches provide a reliable and accurate way to identify botanicals and can be used to ensure the safety and efficacy of plant-based products. This review explores various molecular biotechnology approaches and methods for identifying botanicals.

In this review, benefits and drawbacks of the process of spray drying and nano spray drying with regard to the manufacturing of polymeric particles for pharmaceutical applications are discussed. Spray drying has been used for many years in the food, chemical and pharmaceutical industries for converting liquids into solids, in order to form products of uniform appearance. The construction of spray dryer enables to atomize the liquid into small droplets, which ensures a large surface area for heat and mass transfer, and significantly shortens the processing. Each droplet dries to an individual solid microparticle of characteristic features that can be tailored by optimizing formulation variables and critical process parameters. Since spray drying technology is easy to scale up and can be used for drying almost any drug in a solution or suspension, there are numerous examples of products in clinical use, in which this process has been successfully applied to improve drug stability, enhance bioavailability or control its release rate. In recent years, nano spray drying technology has been proposed as a method for lab-scale manufacturing of nanoparticles. Such an approach is of particular interest at early stages of drug development, when a small amount of new chemical entities is available. Here, the nebulization technique is used for feed atomization, while laminar gas flow in the drying chamber ensures gentle drying conditions. Moreover, electrostatic collectors have gradually replaced cyclone separators, ensuring high effectiveness in producing solid nanoparticles, even if a small volume of the sample is processed.

Background: Mucilage and pectin are both natural polymers with the advantages of availability and biodegradability. Microspheres made from biodegradable polymers can break down naturally after performing their tasks.

Objectives: The study aimed to use mucilage and pectin from the leaves of Talinum triangulare (Jacq.) Willd. as polymer matrices for the formulation of microspheres, with ibuprofen as the model drug.

Material and methods: Both polymers were examined under a microscope and evaluated using measurements of viscosity, density, flow properties, swelling power, elemental analysis, Fourier-transform infrared spectroscopy (FTIR), and the degree of esterification (DE) for pectin. The microspheres were prepared using the ionotropic gelation method and alginate:mucilage/pectin at ratios of 1:1 and 1:2. They were assessed for swellability, drug entrapment effectiveness and drug release profile.

Results: The mucilage particles were ovoid while pectin particles were irregularly shaped. Pectin had higher particle, bulk and tapped densities than mucilage, while mucilage had a higher swelling power and a better flow than pectin. Talinum triangulare pectin is a low-methoxyl pectin with a DE of 7.14%. The FTIR spectra showed no interaction between the polymers and ibuprofen. The surface morphology of the microspheres without ibuprofen was smooth, while those with ibuprofen revealed a spongy-like mesh. The swelling power of the microspheres was higher in phosphate buffer with a pH of 7.2 than in distilled water. The entrapment efficiency ranged within 39.57-60.43% w/w, with microspheres containing alginate:mucilage/pectin ratio of 1:1 having higher entrapment efficiency. Microspheres with polymer at a ratio of 1:1 provided a longer release (>2 h), while microspheres with polymer blend of 1:2 provided an immediate release of ibuprofen.

Conclusions: The polymers of T. triangulare could be used as matrices in microsphere formulations.

Background: Irvingia gabonensis kernel polymer has gained attention in drug delivery systems because of its compatibility and degradation under natural and physiological conditions.

Objectives: This study aimed to evaluate Irvingia gabonensis polymer as a matrix system for the controlled delivery of ibuprofen in comparison to xanthan gum and hydroxypropylmethylcellulose (HPMC).

Material and methods: Irvingia gabonensis polymer was extracted using established methods and dried using the ovenand freeze-drying methods. Ibuprofen tablets were prepared by direct compression and the effects of polymer concentration (10-50%), excipients (lactose, microcrystalline cellulose and dicalcium phosphate dihydrate) and polymers (xanthan gum and HPMC) on the mechanical and drug release properties of the tablets were evaluated. Density measurements and the Heckel and Kawakita equations were used to determine the compression properties of the tablets. Friability, crushing strength and the crushing strength-friability ratio (CSFR) were used to evaluate the mechanical properties of the tablets, while dissolution times were used to evaluate drug release from the matrices. The drug release mechanisms were determined by fitting the dissolution data into classic kinetic equations.

Results: Irvingia gabonensis polymer deformed plastically with a fast onset and a high amount of plastic deformation compared with xanthan gum and HPMC. This polymer was directly compressible and formed intact non-disintegrating tablets; the mechanical and dissolution properties of Irvingia gabonensis polymer tablets generally decreased with increasing concentration of ibuprofen. The ranking of dissolution times was xanthan gum > freeze-dried Irvingia gabonensis > HPMC > oven-dried Irvingia gabonensis. The addition of the excipients improved the mechanical properties of the tablets, aided ibuprofen release, and altered the release kinetics, which was largely defined by the Korsmeyer-Peppas model. Increasing the proportion of xanthan gum and HPMC in the matrices resulted in a decreased amount of ibuprofen released after 9 h, with xanthan gum having a greater effect.

Conclusions: Irvingia gabonensis polymer matrices may be effective in the preparation of controlled release tablets, and their right combination with xanthan gum or HPMC could provide a time-independent release for longer durations.