Preparation and transdermal diffusion evaluation of the prazosin hydrochloride-loaded electrospun poly(vinyl alcohol) fiber mats.

This study reports on the use of electrospun polyvinyl alcohol (PVA) nanofiber mats loaded with prazosin hydrochloride (PRH) as a transdermal drug delivery system, investigating the morphology of electrospun PVA nanofibers, the in vitro release characteristics of the drug from the as-spun fibers, and the influence of permeation enhancer (water-resoluble azone, WSA) on transdermal diffusion of PRH through a rat skin. The same was also conducted on the PRH -loaded as-cast PVA films for comparison. Results indicated that the morphology of PRH-loaded PVA fibers observed by scanning electron microscopy (SEM) relied on the electrospinning processing parameters, and the addition of WSA had obvious effects on the diameter and morphology of electrospun PVA fibers. The PRH-loaded electrospun PVA fiber mats exhibited much higher accumulated release dose and release rate of PRH than as-cast PVA films. And WAS can improve the release amount and rate of PRH from drug-loaded samples. The content of PRH in receiver was more than that in the stratum corneum and in the dermis. It was concluded that the PRH-loaded electropun PVA fiber mats as a transdermal patches can be a promising candidate for the conventional preparation.

Preparation and characterization of folate-chitosan-gemcitabine core-shell nanoparticles for potential tumor-targeted drug delivery.

For the purpose of achieving targeted chemotherapy of pancreatic cancer, we prepared core-shell nanoparticles by coaxial electrospray technology, with folate-chitosan as the polymeric coating material and gemcitabine as the encapsulated drug. The effects of various solution properties and processing parameters on nanoparticles formation were investigated. By optimizing the electrospray parameters, the diameter of the core-shell nanoparticles was in the range of 200-300 nm with drug loading and encapsulation efficiency of 3.91 +/- 0.12% and 85.37 +/- 4.9%. The drug release kinetics revealed a controlled initial burst release followed by a sustained release over a period of 72 h at pH 7.4 and pH 5.0, and at pH 5.0 the drug released more quickly. Moreover, the cellular uptake experiment confirmed that the folate conjugated core-shell nanoparticles had high pancreatic cancer (BXPC3) cells uptake efficiency. And the cell cytotoxicity test displayed that they had remarkable cytotoxicity towards BXPC3 cells. This study indicates that coaxial electrospray is a facile technique in producing core-shell nanoparticles encapsulating hydrophilic small molecule drugs, and clearly infers that the folate conjugated core-shell nanoparticles is very much effective to use as a pancreatic tumor-targeted delivery carrier for anticancer drugs.

Preparation, in vitro and in vivo evaluation of budesonide loaded core/shell nanofibers as oral colonic drug delivery system.

Budesonide (BUD) loaded ethylcellulose (EC)-core/Eudragit S100-shell nanofibers (BUD-core/shell-NFs) have been successfully prepared using a coaxial electrospinning technique. The drug encapsulation efficiency was 90.48%. SEM and TEM analysis showed that fine core-shell structured nanofibers with an average diameter 190 nm and uniform core diameters 74 nm were prepared. The BUD-loaded Eudragit S100/EC composite nanofibers (BUD-NFs) were prepared using a blend electrospinning method and used as a control. In vitro release tests in HCl 0.1 N, phosphate buffer solutions pH 6.8 and 7.4 were studied. Moreover, the colon-specific characteristics were directly proven in vivo by the content of BUD in different segments of the gastrointestinal (GI) tract in rats after oral administration. Taken together, the results confirmed that BUD-core/shell-NFs had desired pH-dependent drug release profile, displayed a sustained and complete drug release in the colon, as well as protected BUD from being released completely in the upper portion of the GI tract. Compared with BUD-NFs, the BUD-core/shell-NFs have much better potential to be developed as oral colon-specific drug delivery system (OCDDS) to overcome the disadvantages of current oral formulations of BUD.

Application of response surface methodology to optimise extraction of flavonoids from fructus sophorae.

Response surface methodology (RSM) based on a central composite design (CCD) was applied to optimise the extraction conditions for flavonoids from fructus sophorae with advantages in terms of resisting flavonoids during the whole process and maximising of extraction yield. Three aglycon forms of the flavonoids, namely, quercetin, kaempferol and isorhamnetin were quantified by high-performance liquid chromatography with ultraviolet detection (HPLC-UV) to estimate extraction yield. The combined effects of independent variables were studied and the optimal extraction conditions were obtained as ethanol concentration, 74.47%; solid-liquid ratio, 17.99 ml/g; temperature, 89.13°C; and extraction time, 2.10h. The reliability of the method was confirmed by recovery experiments, performed under optimal conditions. Recoveries indicated that flavonoids resisted the extraction conditions. The experimental extraction yield under optimal conditions was found to be 10.459%, which was well matched with the predicted values of 10.461%.

Analysis of phthalate migration from plastic containers to packaged cooking oil and mineral water.

The migration of phthalates (PAEs), a class of typical environmental estrogen contaminants in food, from food packaging to packaged food attracts more and more attention worldwide. Many factors will affect the migration processes. The purpose of this study was to evaluate PAE migration from plastic containers to cooking oil and mineral water packed in authentic commercial packaging and stored under various conditions (different storage temperatures, contact times, and storage states (static or dynamic state)) and to identify a potential relationship between the amount and type of PAEs migrated and the lipophilic character of the food matrix. The samples were analyzed by a novel method of liquid chromatography combined with solid-phase extraction by an electrospun nylon 6 nanofibers mat, with PAE detection limits of 0.001 µg/L in mineral water and 0.020 µg/L in cooking oil, respectively. The results demonstrated that the cooking oil was a more suitable medium for the migration of PAEs from packages into foodstuffs than mineral water. Scilicet, the migration potential of the PAEs into foodstuffs, depends on the lipophilic characteristics of the food matrix. The results also demonstrated that migrations were more significant at higher temperature, longer contact time, and higher dynamic frequency; thus, the migration tests should be evaluated with consideration of different storage temperatures and contact times. Mathematical models with good logarithmic relationships were established to demonstrate the relationship between the PAE migration and food/packaging contact time for different storage temperatures. These established mathematical models would be expected to become a set of practical tools for the prediction of PAE migration.

Development and validation of a nylon6 nanofibers mat-based SPE coupled with HPLC method for the determination of docetaxel in rabbit plasma and its application to the relative bioavailability study.

A simple and sensitive HPLC method was established and validated for the determination of docetaxel (DTX) in rabbit plasma. Biosamples were spiked with paclitaxel (PCX) as an internal standard (I.S.) and pre-treated by solid-phase extraction (SPE). The SPE procedure followed a simple protein digestion was based on nylon6 electrospun nanofibers mats as sorbents. Under optimized conditions, target analytes in 500 microL of plasma sample can be completely extracted by only 2.5mg nylon6 nanofibers mat and eluted by 100 microL solvent. The HPLC separation was obtained on C18 column and UV detector was used to quantify the target analytes. The extraction recovery was more than 85%; the standard curve was linear over the validated concentrations range of 10-5000 ng/mL and the limit of detection was 2 ng/mL. The inter-day coefficient of variation (CV%) of the calibration standards was below 5.0% and the mean accuracy was in the range of 92.8-113.4%. Moreover, analysing quality control plasma samples in 3 days, the results showed that the method was precise and accurate, for the intra- and inter-day CV% within 10% and the accuracy from 96.0% to 114.0%. The developed and validated method was successfully applied to relative bioavailability study for the preclinical evaluation of a new injectable DTX-sulfobutyl ether beta-cyclodextrin (DTX-SBE-beta-CD) inclusion complex freeze-dried powder (test preparation), compared with the reference preparation (DTX injection, Taxotere) in healthy rabbits. On the basis of the mean AUC(0-t) and AUC(0-infinity), the relative bioavailability of the test preparation was found to be 113.1%.