جستجوی مقالات مرتبط با کلیدواژه « pvp » در نشریات گروه « پزشکی »

This study presents a new design of multilayered PMMA dental composite material combining electrospun continuous composite polyvinylpyrrolidone (PVP) nanofibers filled with zirconia (ZrO2) nanoparticles and two-component self-cure PMMA dental resin. The aim is to improve the mechanical properties of dental PMMA material via the large surface area of electrospun nanofibers, the toughening effect of PVP and ZrO2 nanofillers. First, PVP/ZrO2 composite nanofibers with different ZrO2 contents of 5%, 10% and 20% (wt. % of PVP) were prepared by electrospinning. Then, multilayered samples containing alternating PMMA resin and electrospun composite nanofiber mats with different ZrO2 contents were manufactured by lay-up process. Samples containing single and double layers of nanofiber mats were prepared and cured in a water bath dental acrylic curing device in order to prepare composites without any void. FTIR and SEM results reveal that PVP enables good interfacial interactions and compatibility between the nanofibers and PMMA matrix. The mechanical properties are improved as an increase of the flexural strength up to 83% and 67% is observed for PMMA/PVP/ZrO2-10s and PMMA/PVP/ZrO2-20d samples, respectively. The presence of PVP nanofiber layers significantly improves the flexural toughness, especially for samples reinforced with a single layer of nanofibers where improvements up to 169% and 153% are observed for PMMA/PVP/ZrO2-5s and PMMA/PVP/ZrO2-10s composite samples respectively. The micro-hardness is also higher for composite samples compared to neat PMMA dental material. The overall results clearly depict a noticeable enhancement of the mechanical properties, especially the flexural toughness of PMMA dental material

In this research, chitosan Schiff base was prepared from the reaction of chitosan with carbonyl group of 4-nitro benzaldehyde. The gold and silver nanoparticles were prepared by the onion peels extract as reducing agent. The prepared AgNPs and AuNPs were characterized by UV-visible spectroscopy, SEM microscopy and XRD analysis. Polymer blends of Chitosan Schiff base, PVA and PVP were synthesis by solution casting method, Chitosan Schiff base / PVA / PVP Au and Ag nanocomposites were manufacture. the polymer blends and nano composites were characterized by FT-IR, SEM, DSC, and TGA, the blends and nano composites showed good activity against different gram +ve and gram -ve bacterium kinds, The antimicrobial activities toward the tested microorganisms, which can be attributed to chemical structure of Chitosan Schiff base, the presence of the Schiff-base molecule's imine group (C=N) with its 𝜋 - electrons is thought to improve the molecule's lipophilicity, making it easier for it to enter the microbe's cell membrane, the nano composites showed good results in inhibition of breast cancer cell line MCF7.

The goal of the current study is to design and evaluate transdermal patches of rabeprazole sodium (RPS).

Transdermal patches of RPS were prepared using polymers such as hydroxyl propyl cellulose (HPC-EF), polyvinyl pyrrolidone K-30 (PVP K-30), and polyvinyl pyrrolidone K-90 (PVP K-90) as film formers, polyethylene glycol (PEG-400) as a plasticizer, and Tween-80 and azone as permeation enhancers. The solvent casting technique was employed to develop the patches using aluminum foil as the backing membrane. These patches were evaluated for compatibility using Fourier transform infrared (FTIR) spectrophotometry and for content by ultraviolet (UV) spectrophotometry besides physicochemical properties such as thickness, adhesion, moisture content, moisture loss, and folding endurance. The patches were tested for in vitro release in United States Pharmacopoeia (USP) dissolution apparatus V and ex vivo permeation across shed snake skin in vertical Franz diffusion cell (FDC).

The characteristic FTIR spectra of RPS were also evident in the spectra of the patches, indicating drug-excipient compatibility. In vitro drug release indicated that the release of the drug was maximum from patches composed of HPC-EF (60.08±1.04%), which was much higher when compared with patches made of PVP K-30 (47.53±0.40%) and PVP K-90 (42.84±0.74%). The ex vivo permeation studies suggested that about 116.79±1.99 µg/cm2 of the drug was permeated in 24 h from formulation patches composed of HPC-EF that resulted in flux of nearly 7.06 µg/cm2 /h.

The studies indicated that feasibility of transdermal delivery of rabeprazole as a patch of 16 cm2 is likely to suffice the therapeutic requirement.

Currently, a laser is a popular technology in urological surgeries. The important laser-related issue is the time when a surgeon reaches an acceptable level of safety and efficacy using laser technology.

In this review, we aimed to assess the learning curves of three types of surgeries in urology, including photoselective vaporization of the prostate (PVP), holmium laser enucleation of the prostate (HoLEP) and retrograde intra-renal surgeries (RIRSs). Here, we searched Medline, Web of Science, Google Scholar, EMBASE, and Scopus for such keywords as Urology, laser, laser vaporization, prostate, nephrolithiasis, benign prostatic hyperplasia (BPH), and learning curve.

We evaluated 14 studies about PVP, 17 about RIRS, and 29 studies about HoLEP. Also, we separately discussed the learning curves of these three kinds of surgeries in detail.

All the urologists, even expert surgeons, should attend a formal training course and have a skilled tutor present at their first cases

Benign prostatic hyperplasia (BPH) is a disease of the prostate commonly seen in elderly males known to cause lower urinary tract symptoms (LUTS) that may require surgery as a part of treatment. Transurethral resection of the prostate (TURP) is considered the gold standard of surgical treatment, but it is not without complications. Laser photoselective vaporisation of the prostate (PVP), introduced in 1998 as an 80 W Nd:YAG laser which passed through a KTP (potassium-titanyl-phosphate) crystal, emerged as a safe alternative to TURP in selected cases. A recent upgrade to the Greenlight XPS 180 W powered with an LBO (lithium triborate) crystal has been available for use since 2012. Data on the use of this new upgrade is still being collected and analysed, especially in patients with large prostates or high risk cases. We analysed cases done at Jaslok Hospital over a 2-year period. A total of 34 patients who underwent Laser PVP using XPS 180W for LUTS due to BPH at Jaslok Hospital were part of this study. We analysed the pre- and postoperative variables and the intraoperative parameters of all patients. The XPS 180W was found to be safe and efficacious. Eighteen patients were high-risk cases, classified as ASA (American Society of Anesthesiologists) Classes 3 and 4. Average postoperative catheter duration was 40.18 hours. In prostates of size <80 mL, an average of 229 kJ of energy was used. In large prostates (>80 mL), an average of 390 kJ of energy was used. No major complications were seen in any of the high-risk patients, classified as Clavien Dindo Class 3 and 4. The postoperative drop in IPSS (International Prostate Symptom Score) was 8.7. We found that Green Light Laser XPS 180W may be used for large (>80 g) prostates, hitherto an indication for open surgery, and that it may be used in high-risk patients, who were otherwise unfit for TURP. It is safe and efficacious. Further, multicenter trials are required to confirm the findings.

Solid dispersion formulation is the most promising strategy to improve oral bioavailability of poorly water soluble drugs. The aim of this study was to compare the effect of polyvinylpyrrolidone K30 (PVP) and poloxamer-188 (PLX) as carrier in solid dispersion formulations of celecoxib (CLX). Solid dispersions of CLX:PVP or CLX:PLX were prepared at different ratios (2:1, 1:1, 1:2, 1:4, 1:6) by solvent evaporation and melting methods, respectively. The characterization of samples was performed using differential scanning calorimetery (DSC), X-Ray powder diffraction (XRPD) and Fourier transform infrared spectroscopy (FT-IR). The Gordon-Taylor equation was used to estimate the Tg of solid dispersion systems and the possibility of the interaction between CLX and PVP. Also, the dissolution rate of all samples was determined. DSC and XRPD analyses confirmed the presence of amorphous state of drug in solid dispersion systems. FT-IR studies showed CLX could participate in hydrogen bonding with PVP whilst no specific interaction between CLX and PLX was observed. Both PVP and PLX enhanced the dissolution rate of drug in solid dispersion samples. The dissolution rate was dependent on the ratio of drug: carrier. Interestingly, the solid dispersion samples of PLX at 2:1 and 1:1 drug: carrier showed slower dissolution rate than pure CLX, whilst these results were not observed for PVP. The effect of PVP on dissolution rate enhancement was more pronounced compared to the other carrier. Having a higher Tg and more effect on dissolution rate, PVP could be considered as a more suitable carrier compared to PLX in solid dispersion formulation of CLX.

The present work investigated the preparation of biodegradable beads with alginate polymer by ionotropic gelation method to improve the control release properties of the antibiotic rifampicin. Ionotropic gelation method was applied to prepare beads using calcium chloride (CaCl2) as cationic component and alginate as an anionic component. In this method, adding 0.5% w/v polyvinyl alcohol (PVA) to sodium alginate (3.0% w/v) and 2% w/v of polyvinyl pyrrolidone (PVP) to the CaCl2 solution were maintained to study the drug-loading and its released characteristics. The results showed that the addition of PVA and PVP significantly improved drug-loading, encapsulation efficiency and release characteristics. This demonstrates that the ionic gelation of alginate molecules offers a flexible and easily controllable process.