Polymeric nanofibers generated via electrospinning offer a promising platform for drug delivery systems. This study examines the application of electrospun polyvinyl alcohol (PVA) nanofibers for ...controlled lysozyme (LZM) delivery. By using various PVA grades, such as the degree of polymerization/hydrolysis, this study investigates their influence on nanofiber morphology and drug-release characteristics. LZM-loaded PVA monolithic nanofibers having 50% drug content exhibit efficient entrapment, wherein rapid dissolution is achieved within 30 min. The initial burst of LZM from the nanofiber was reduced as the LZM content was lowered. The initial dissolution is greatly influenced by the choice of PVA grade used; fully hydrolyzed PVA nanofibers demonstrate controlled release due to the reduced water solubility of PVA. Furthermore, coaxial electrospinning, which creates core–shell nanofibers with polycaprolactone as a controlled release layer, enables sustained LZM release over an extended period. This study confirms a correlation between PVA characteristics and controlled drug release and provides valuable insights into tailoring nanofiber properties for pharmaceutical applications.
We attempted to improve the solubility of poorly water-soluble drugs by preparing drug-loaded polyvinyl alcohol (PVA) nanofibers as a solid dispersion system via emulsion electrospinning. Probucol ...(PBC), a poorly water-soluble drug, was used as a model drug. Nanofibers were electrospun using an oil/water (o/w) emulsion consisting of PBC dissolved in an immiscible solvent, such as ethyl acetate, and an aqueous PVA phase. PBC-containing PVA nanofibers with diameters ranging from 300 to 600 nm were obtained by electrospinning from o/w emulsions. The physical properties of the nanofibers were affected by the degrees of polymerization and hydrolysis of the PVA grades. In PVA nanofibers prepared without a surfactant, PBC existed in an amorphous state, and the dissolution of PBC was greatly improved. PBC dissolution was lower in PVA nanofibers with 30% PBC content compared to those with 11% or 20% PBC. In PVA nanofibers prepared using the surfactant polysorbate 80 as an emulsifier, PBC was partially crystallized; however, the PBC was homogenously dispersed, and dissolution was improved, even in PVA nanofibers containing 30% PBC. PVA nanofibers produced by o/w emulsion electrospinning were demonstrated to be suitable solid dispersion systems enabling robust controlled release of poorly water-soluble drugs.
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Differences between the effects of intravenous sedation with midazolam (MID) and dexmedetomidine (DEX) on the cerebral function of elderly patients with severe dementia are unclear. This study aimed ...to compare the effects of intravenous sedation with MID or DEX on parameters such as brain waves and cerebral blood flow (CBF). This cross-over study analyzed 12 patients with severe dementia, with each patient receiving both drug treatments. Each drug was administered until a Modified Observer's Assessment of Alertness/Sedation (OAA/S) score of 2 was reached. Bispectral index (BIS) and normalized tissue hemoglobin index (nTHI), which reflects CBF using near-infrared spectroscopy, were measured. Mann-Whitney U, Wilcoxon signed-rank, and Friedman tests, and multiple regression analysis were performed. While a similar decline in BIS values was observed in both groups (P < 0.030), there was a significant decrease in nTHI up to 11% in the MID group (P = 0.005). In the DEX group, nTHI values did not differ from baseline. When an OAA/S score of 2 was just achieved, CBF in the MID group (- 5%) was significantly lower than in the DEX group (± 0%). In dementia patients, sedation with MID resulted in a decrease in CBF, while the CBF value was maintained during sedation with DEX.
This study aimed to develop polyvinyl alcohol (PVA) nanofibers encapsulating 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)/siRNA complexes via electrospinning for the delivery of nucleic ...acid-based drugs. It also focused on the influence of the intrinsic properties of PVA on the efficacy of the system. PVA nanofibers, with diameters of 300–400 nm, were obtained, within which the siRNA remained intact and the DOTAP/siRNA complexes were uniformly dispersed. By incorporating DOTAP/siRNA complexes into the PVA nanofibers and assessing the impact of their RNA interference (RNAi) activity in A549-Luc cells, a stable inhibition of luciferase expression was observed. An examination of the nanofiber preparation process revealed that even when DOTAP or siRNA were added separately to the PVA solution without forming complexes, the RNAi effect was retained. The DOTAP/siRNA complexes released from the PVA nanofibers were internalized by the cells, with some PVA residues remaining on their surfaces. The significance of the degree of hydrolysis and polymerization of PVA on the performance of nanofibers was highlighted. Notably, PVA with a low degree of hydrolysis substantially enhanced RNAi effects, with luciferase expression inhibition reaching 91.5 ± 0.7%. Nanofibers made of PVA grades with anionic or cationic modifications were also evaluated, suggesting that they affect the efficacy of siRNA delivery. The insights obtained suggest avenues for future research to optimize drug delivery systems further.
A series of pyrene derivatives containing thienyl groups, 1−3, has been prepared using the Suzuki coupling reaction. Recrystallization from solution and physical vapor transport (PVT) method afforded ...different types of crystals of 1. From the mixture of isomers of 2, the 1,8-isomer preferably crystallized from solution, whereas the 1,6-isomer crystal was obtained by the PVT method. Fabricating single-crystal-based field-effect transistors of the above compounds we directly compared the field-effect performance between the devices of the two isoforms of 1 and those of the two isomers of 2. Though the overlap integrals were calculated to be only ∼10−3, the best hole mobility reached 0.02 cm2 V−1 s−1 for one of the single crystals of 1. Intriguingly, for both 1 and 2 only one type of the crystal shows the field-effect characteristics, indicating the significance of molecular packing even in the absence of band transport among the poorly coupled molecules. The estimated intermolecular overlap integrals for each compound also imply that the minimum overlap integral of ∼10−2 eV is required for detection of the field-effect characteristics.
Purpose
Radiofrequency ablation for liver tumors (liver RFA) is widely performed under ultrasound guidance. However, discriminating between the tumor and the needle is often difficult because of ...cavitation caused by RFA-induced coagulation. An unclear ultrasound image can lead to complications and tumor residue. Therefore, image-guided navigation systems based on fiducial registration have been developed. Fiducial points are usually set on a patient’s skin. But the use of internal fiducial points can improve the accuracy of navigation. In this study, a new device is introduced to use internal fiducial points using 2D US.
Methods
3D Slicer as the navigation software, Polaris Vicra as the position sensor, and two target tumors in a 3D abdominal phantom as puncture targets were used. Also, a new device that makes it possible to obtain tracking coordinates in the body was invented. First, two-dimensional reslice images from the CT images using 3D Slicer were built. A virtual needle was displayed on the two-dimensional reslice image, reflecting the movement of the actual needle after fiducial registration. A phantom experiment using three sets of fiducial point configurations: one conventional case using only surface points, and two cases in which the center of the target tumor was selected as a fiducial point was performed. For each configuration, one surgeon punctured each target tumor ten times under guidance from the 3D Slicer display. Finally, a statistical analysis examining the puncture error was performed.
Results
The puncture error for each target tumor decreased significantly when the center of the target tumor was included as one of the fiducial points, compared with when only surface points were used.
Conclusion
This study introduces a new device to use internal fiducial points and suggests that the accuracy of image-guided navigation systems for liver RFA can be improved by using the new device.
This study explored the development of solid dispersions of probucol (PBC), a poorly water-soluble drug, embedded within polyvinyl alcohol (PVA) nanofibers at a high concentration (30 %) via emulsion ...electrospinning. This study addressed the issues of low solubility and dissolution rates of such drugs by examining the incorporation of various types of silica particles—Aerosil 200 (A200), Sylisia 320 (SY320), Aerosil R972, and Sylophobic 100—as additives in oil-in-water emulsions. The results revealed that regardless of their hydrophilic or hydrophobic properties, silica particles preserved the amorphous state of PBC within the nanofibers without altering its crystallinity. Notably, all nanofibers embedded with silica particles demonstrated improved drug solubility compared to those without silica. This suggests that silica plays a role in mitigating the reduced solubility of drugs associated with their higher concentrations. Stability assessments of nanofibers embedded with A200 and SY320 under accelerated conditions revealed that A200 nanofibers preserved drug crystallinity and solubility, thus exhibiting superior storage stability. In contrast, SY320 nanofibers underwent drug crystallization, leading to a decrease in solubility upon storage. In conclusion, this study highlights the potential of silica particles in enhancing the solubility and stability of PBC in PVA nanofibers, suggesting that emulsion electrospinning with suitable silica additives is an effective strategy for developing advanced drug delivery systems for poorly water-soluble drugs.
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•Polyvinyl alcohol nanofibers with high probucol content enhanced drug solubility.•Silica additives ensured that probucol remained amorphous within nanofibers.•All tested silica additives significantly improved drug solubility in nanofibers.•Optimal Aerosil 200 addition to nanofibers improved drug solubility and stability.
