[Expression and regulation of drug transporters in placenta].

Placenta, an important organ, mediates the exchange of nutrients and metabolites between mother and fetus. The transporters, including ATP-binding cassette (ABC) transporters and solute carrier (SLC), expressed in the syncytiotrophoblast play a vital role in substance exchange. Some transporters, such as organic cation transporters (OCTs) and organic anion transporters (OATs), mediate the uptake of endogenous substances and drugs. Some transporters, such as P-glycoprotein (P-gp), breast cancer resistance protein (BCRP) and multidrug resistance-associated proteins(MRPs), can excrete their substrates from the syncytiotrophoblast to the maternal circulation. However, the expression and activity of these transporters are not uniform throughout the gestation period, since they can be affected by physiological and pathological changes during pregnancy or drugs. Thus, an understanding of the role of placental transporters and the variation in their expression and activity in response to physiological and pathological changes is essential for efficient and safe therapy during pregnancy, and it also has important value in the development of drug treatment in pregnancy.

Enhanced Percutaneous Delivery of Methotrexate Using Micelles Prepared with Novel Cationic Amphipathic Material.

BACKGROUND: Methotrexate (MTX) is an antiproliferative drug widely used to treat inflammatory diseases and autoimmune diseases. The application of percutaneous administration is hindered due to its poor transdermal penetration. To reduce side effects and enhanced percutaneous delivery of MTX, novel methotrexate (MTX)-loaded micelles prepared with a amphiphilic cationic material, N,N-dimethyl-(N',N'-di-stearoyl-1-ethyl)1,3-diaminopropane (DMSAP), was designed. MATERIALS AND METHODS: DMSAP was synthesized via three steps using simple chemical agents. H nuclear magnetic resonance and mass spectroscopy were used to confirm the successful synthesis of DMSAP. A safe and non-toxic phosphatidylcholine, soybean phosphatidylcholine (SPC), was added to DMSAP at different ratios to form P/D-micelles. Then, MTX-entrapped micelles (M/P/D-micelles) were prepared by electrostatic adsorption. The physicochemical properties and blood stability of micelles were examined thoroughly. In addition, the transdermal potential of the micelles was evaluated by permeation experiments. RESULTS: In aqueous environments, DMSAP conjugates could self-assemble spontaneously into micelles with a low critical micelle concentration (CMC) of 0.056 mg/mL. Stable, spherical MTX-entrapped micelles (M/P/D-micelles) with a size of 100-120 nm and high zeta potential of +36.26 mV were prepared. In vitro permeation studies showed that M/P/D-micelles exhibited superior skin permeability and deposition of MTX in the epidermis and dermis compared with that of free MTX. CONCLUSION: These special novel cationic M/P/D-micelles can enhance the permeability of MTX and are expected to be a promising percutaneous delivery system for therapy skin diseases.

Co-Delivery of Curcumin and Paclitaxel by "Core-Shell" Targeting Amphiphilic Copolymer to Reverse Resistance in the Treatment of Ovarian Cancer.

BACKGROUND: Ovarian cancer is a common malignancy in the female reproductive system with a high mortality rate. The most important reason is multidrug resistance (MDR) of cancer chemotherapy. To reduce side effects, reverse resistance and improve efficacy for the treatment of ovarian cancer, a "core-shell" polymeric nanoparticle-mediated curcumin and paclitaxel co-delivery platform was designed. METHODS: Nuclear magnetic resonance confirmed the successful grafting of polyethylenimine (PEI) and stearic acid (SA) (PEI-SA), which is designed as a mother core for transport carrier. Then, PEI-SA was modified with hyaluronic acid (HA) and physicochemical properties were examined. To understand the regulatory mechanism of resistance and measure the anti-tumor efficacy of the treatments, cytotoxicity assay, cellular uptake, P-glycoprotein (P-gp) expression and migration experiment of ovarian cancer cells were performed. In addition, adverse reactions of nanoformulation to the reproductive system were examined. RESULTS: HA-modified drug-loaded PEI-SA had a narrow size of about 189 nm in diameters, and the particle size was suitable for endocytosis. The nanocarrier could target specifically to CD44 receptor on the ovarian cancer cell membrane. Co-delivery of curcumin and paclitaxel by the nanocarriers exerts synergistic anti-ovarian cancer effects on chemosensitive human ovarian cancer cells (SKOV3) and multi-drug resistant variant (SKOV3-TR30) in vitro, and it also shows a good anti-tumor effect in ovarian tumor-bearing nude mice. The mechanism of reversing drug resistance may be that the nanoparticles inhibit the efflux of P-gp, inhibit the migration of tumor cells, and curcumin synergistically reverses the resistance of PTX to increase antitumor activity. It is worth noting that the treatment did not cause significant toxicity to the uterus and ovaries with the observation of macroscopic and microscopic. CONCLUSION: This special structure of targeting nanoparticles co-delivery with the curcumin and paclitaxel can increase the anti-tumor efficacy without increasing the adverse reactions as a promising strategy for therapy ovarian cancer.

Biodegradable and complexed microspheres used for sustained delivery and activity protection of SOD.

To develop a new protein delivery system for superoxide dismutase (SOD), biodegradable materials like poly(DL-lactide-co-glycolide) (PLGA), alginate, and chitosan were used for preparing PLGA microspheres and alginate-chitosan microspheres, which were used for encapsulating protein. Alginate-chitosan microspheres showed much higher entrapment efficiency (91.08% +/- 1.28%) than that of PLGA microspheres (36.42% +/- 1.81%). In vitro release study showed that SOD presented a sustained release character in the preparation of these biodegradable materials. After 15 days, 43.72% +/- 0.43% of protein was released from alginate-chitosan microspheres, while there was 62.96% +/- 3.95% of protein release from PLGA microspheres. However, alginate-chitosan demonstrated that it was a better material to control the burst release of protein from microspheres. Furthermore, SOD activity in microspheres was evaluated, and the results showed that microspheres protected the activity of protein to some extent. Finally, PLGA-alginate-chitosan complex microspheres were constructed and the release character in vitro demonstrated that this preparation could not only prolong the release of drug but also decrease the burst release.

Effects of additives and processing parameters on the initial burst release of protein from poly(lactic-co-glycolic acid) microspheres.

The aim of this study is to investigate both the effects of hydrophilic additives and combined processing parameters on the in vitro release of a model protein, bovine serum albumin (BSA), from poly(lactic-co-glycolic acid) (PLGA) microspheres. Additives including beta-cyclodextrin, HP-beta-cyclodextrin, poly(ethylene glycol) (PEG) 6000, and sorbitol, and processing parameters such as the poly(vinyl alcohol) (PVA) concentration, emulsification temperature, aqueous/oil phase, evaporation method, and dehydration method were evaluated. PLGA microspheres were all prepared by the double-emulsion solvent extraction/evaporation method, and the results showed that no statistically significant differences of particle sizes and entrapment efficiencies appeared. Interestingly, the initial burst releases were markedly changed by both additives and processing parameters. Initial burst releases were accelerated by hydrophilic additives except for PEG 6000 and were retarded by the formulation composed of higher PVA concentration, tween-20 as an emulsifier in the internal aqueous phase, glycerol in the oil phase, and inorganic salt in the external aqueous phase, and operated at low temperature. Scanning electron microscopy showed that the more porous and dimpled the structure on the surface of the PLGA microspheres, the larger the initial burst release. The microspheres that displayed a relatively smooth and compact surface showed the least burst release.

A comparison between conventional liposome and drug-cyclodextrin complex in liposome system.

A drug-cyclodextrin complex in liposome system was prepared in order to make a comparison with conventional risperidone-loaded liposome. Thin film hydration, reverse phase evaporation and ethanol injection methods were taken as preparation means to obtain the two types of liposome. Differential thermal analysis (DTA) and transmission electron microscopy (TEM) were used to investigate the thermal characters of inclusion complexes and morphology of liposome, respectively. Particle size, zeta potential and encapsulation efficiency were studied by light scattering analysis and ultrafiltration. In vitro release was carried out in the pH 7.4 phosphate buffer solution and samples were collected at the certain time. As a result, drug-cyclodextrin complex in liposome prepared by various methods displayed lower encapsulation efficiency than conventional liposome. However, size was larger and its stability was better than the latter. The second release phase of novel delivery system was slightly slower after initial burst release at the first phase, while the conventional liposome displayed a more regular trait. Thus, the novel liposome have potential to be developed as co-administration formulation with long-acting injection.

Efficient delivery of Notch1 siRNA to SKOV3 cells by cationic cholesterol derivative-based liposome.

A novel cationic cholesterol derivative-based small interfering RNA (siRNA) interference strategy was suggested to inhibit Notch1 activation in SKOV3 cells for the gene therapy of ovarian cancer. The cationic cholesterol derivative, N-(cholesterylhemisuccinoyl-amino-3-propyl)-N, N-dimethylamine (DMAPA-chems) liposome, was incubated with siRNA at different nitrogen-to-phosphate ratios to form stabilized, near-spherical siRNA/DMAPA-chems nanoparticles with sizes of 100-200 nm and zeta potentials of 40-50 mV. The siRNA/DMAPA-chems nanoparticles protected siRNA from nuclease degradation in 25% fetal bovine serum. The nanoparticles exhibited high cell uptake and Notch1 gene knockdown efficiency in SKOV3 cells at an nitrogen-to-phosphate ratio of 100 and an siRNA concentration of 50 nM. They also inhibited the growth and promoted the apoptosis of SKOV3 cells. These results may provide the potential for using cationic cholesterol derivatives as efficient nonviral siRNA carriers for the suppression of Notch1 activation in ovarian cancer cells.

Hyaluronic acid reagent functional chitosan-PEI conjugate with AQP2-siRNA suppressed endometriotic lesion formation.

To identify a new drug candidate for treating endometriosis which has fewer side effects, a new polymeric nanoparticle gene delivery system consisting of polyethylenimine-grafted chitosan oligosaccharide (CSO-PEI) with hyaluronic acid (HA) and small interfering RNA (siRNA) was designed. There was no obvious difference in sizes observed between (CSO-PEI/siRNA)HA and CSO-PEI/siRNA, but the fluorescence accumulation in the endometriotic lesion was more significant for (CSO-PEI/siRNA)HA compared with CSO-PEI/siRNA due to the specific binding of HA to CD44. In addition, the (CSO-PEI/siRNA)HA nanoparticle gene therapy significantly decreased the endometriotic lesion sizes with atrophy and degeneration of the ectopic endometrium. The epithelial cells of ectopic endometrium from rat models of endometriosis showed a significantly lower CD44 expression than control after treatment with (CSO-PEI/siRNA)HA. Furthermore, observation under an electron microscope showed no obvious toxic effect on the reproductive organs. Therefore, (CSO-PEI/siRNA)HA gene delivery system can be used as an effective method for the treatment of endometriosis.

[Preparation of alginate-chitosan-poly (lactic-co-glycolic acid) composite microsphere and its regulation of protein release].

AIM: To elevate the encapsulation efficiency, decrease the burst release and improve the release of protein entrapped in poly (lactic-co-glycolic acid) (PLGA) microspheres. The bovine serum albumin (BSA) composite microspheres of alginate-chitosan-PLGA were prepared and the release characteristics of BSA from this composite microspheres were studied. METHODS: The much smaller calcium alginate microcapsules were first prepared by a modified emulsification method in an isopropyl alcohol-washed way and coated with chitosan, then the alginate-chitosan microcapsules were further entrapped in PLGA to form the composite microspheres. The protein concentration was determined using a BCA protein assay kit. The release profiles were changed with various formulation factors. RESULTS: The average diameter of the composite microcapsules was about 30 microm. Comparing with 60% to 70% of the conventional PLGA microspheres, the average encapsulation efficiency was more than 80%, and the burst releases in phosphate buffer solution of the composite microspheres decreased from 40% and 50% to 25% and further to 5% in saline solution. CONCLUSION: The novel composite microspheres were prepared, the drug encapsulation efficiency increased and the burst release decreased. The desired release profiles could be obtained by regulating the ratios of PLG and PLA in the composite microspheres.

Gene therapy of endometriosis introduced by polymeric micelles with glycolipid-like structure.

To reduce the side effects and improve the lack of clinical treatment countermeasures in endometriosis chemotherapy, a polymeric micelle gene delivery system composed of lipid grafted chitosan micelles (CSO-SA) and the pigment epithelium derived factor (PEDF) was designed. Due to the cationic property, the glycolipid-like micelles could compact the PEDF to form complexes nanoparticles. The complexes nanoparticles with an N/P at 9.6 had 135.6 nm volume average hydrodynamic diameters with a narrow size distribution, and 6.4 ± 0.1 mV surface potential. PEDF can be distributed to endometriotic lesions in a rat model of peritoneal endometriosis mediated by CSO-SA via the intravenous injection. It showed that the CSO-SA/PEDF nanoparticles gene therapy caused decrease in the sizes of the endometriotic lesions and atrophy and degeneration of ectopic endometrium significantly. And it showed no toxicity to the reproductive organs under electron microscope observation. In addition, a reduction in microvessel density labeled by Von Willebrand factor was observed and no decrease in α-Smooth Muscle Actine-positive mature vessels. And the index of apoptotic was increased significantly in endometriotic lesions of CSO-SA/PEDF group. So, glycolipid-like structure micelles mediated PEDF gene delivery system could be used as an effective treatment approach for endometriosis disease.

Hydrophilic biodegradable microspheres of interferon-alpha and its pharmacokinetics in mice.

The goal of this research was to prepare a kind of hydrophilic sustained release microspheres of interferon-alpha (IFN-alpha), alginate-chitosan microspheres (ACM) of IFN, and investigate its pharmacokinetics in mice. Alginate microspheres of IFN-alpha were first prepared by an emulsion method and further incubated in chitosan to form IFN-ACM. The influences of isopropanol, bovine serum albumin (BSA), and pH adjustment by isoelectric point of IFN were studied. The optimized IFN-ACM was obtained with smooth and round morphology, size of 2.18 +/- 0.43 microm and entrapment efficiency of 40%. All the concentrations of IFN-alpha were determined by IFN assay kits. Finally the pharmacokinetics of IFN-ACM suspension was studied in ICR mice by intramuscular (I.M.) routes. Compared with IFN solution, C(max) of IFN-ACM reduced 2.3-fold, and time to achievement of maximum serum concentrations (T(max)) increased 4-fold. Meanwhile the area under the concentration-time curve (AUC) was the same as that of solution. The concentration-time profiles presented the prolonged serum levels of IFN from IFN-ACM.

A protein delivery system: biodegradable alginate-chitosan-poly(lactic-co-glycolic acid) composite microspheres.

In the present study we developed alginate-chitosan-poly(lactic-co-glycolic acid) (PLGA) composite microspheres to elevate protein entrapment efficiency and decrease its burst release. Bovine serum albumin (BSA), which used as the model protein, was entrapped into the alginate microcapsules by a modified emulsification method in an isopropyl alcohol-washed way. The rapid drug releases were sustained by chitosan coating. To obtain the desired release properties, the alginate-chitosan microcapsules were further incorporated in the PLGA to form the composite microspheres. The average diameter of the composite microcapsules was 31+/-9microm and the encapsulation efficiency was 81-87%, while that of conventional PLGA microspheres was just 61-65%. Furthermore, the burst releases at 1h of BSA entrapped in composite microspheres which containing PLGA (50:50) and PLGA (70:30) decreased to 24% and 8% in PBS, and further decreased to 5% and 2% in saline. On the contrary, the burst releases of conventional PLGA microspheres were 48% and 52% in PBS, respectively. Moreover, the release profiles could be manipulated by regulating the ratios of poly(lactic acid) to poly(glycolic acid) in the composite microspheres.