Mitochondrial targeted doxorubicin derivatives delivered by ROS-responsive nanocarriers to breast tumor for overcoming of multidrug resistance.

Multidrug resistance (MDR) is a serious challenge in chemotherapy and also a major threat to breast cancer treatment. As an intracellular energy factory, mitochondria provide energy for drug efflux and are deeply involved in multidrug resistance. Mitochondrial targeted delivery of doxorubicin can overcome multidrug resistance by disrupting mitochondrial function. By incorporating a reactive oxygen species (ROS)-responsive hydrophobic group into the backbone structure of hyaluronic acid - a natural ligand for the highly expressed CD44 receptor on tumor surfaces, a novel ROS-responsive and CD44-targeting nano-carriers was constructed. In this study, mitochondria-targeted triphenylphosphine modified-doxorubicin (TPP-DOX) and amphipathic ROS-responsive hyaluronic acid derivatives (HA-PBPE) were synthesized and confirmed by 1H NMR. The nanocarriers TPP-DOX @ HA-PBPE was prepared in a regular shape and particle size of approximately 200 nm. Compared to free DOX, its antitumor activity in vitro and tumor passive targeting in vivo has been enhanced. The ROS-responsive TPP-DOX@HA-PBPE nanocarriers system provide a promising strategy for the reverse of MDR and efficient delivery of doxorubicin derivatives into drug-resistant cancer cells.

Doxorubicin derivative loaded acetal-PEG-PCCL micelles for overcoming multidrug resistance in MCF-7/ADR cells.

Objective: This study was aimed to develop DOX-TPP loaded acetal-PEG-PCCL micelles to improve the clinical efficacy of drug resistance tumor. Significance: Chemotherapy is one of the main treatments for breast cancer but is plagued by multidrug resistance (MDR). DOX-TPP-loaded micelles can enhance the specific concentration of drugs in the tumor and improve the efficacy and overcome MDR. Methods: In this study, DOX-TPP-loaded micelles based on acetal-PEG-PCCL were prepared and their physicochemical properties were characterized. The cellular uptake and ability to induce apoptosis of the micelles was confirmed by flow cytometry in MCF-7/ADR cells. In addition, cytotoxicity of the micelles was studied in MCF-7 cells and MCF-7/ADR cells. Confocal is used to study the subcellular distribution of DOX. Free DOX-TPP or DOX-TPP-loaded acetal-PEG-PCCL micelles were administered via intravenous injection in the tail vain for the biodistribution study in vivo. Results: The diameter of micelles was about 102.4 nm and their drug-loading efficiency is 61.8%. The structural characterization was confirmed by 1H NMR. The micelles exhibited better antitumor efficacy compared to free doxorubicin in MCF-7/ADR cells by MTT assay. The apoptotic rate and the cellular uptake of micelles were significantly higher than free DOX and DOX-TPP. Micelles can efficiently deliver mitochondria-targeting DOX-TPP to tumor cells. The result of bio-distribution showed that the micelles had stronger tumor infiltration ability than free drugs. Conclusions: In this study, mitochondriotropic DOX-TPP was conjugated to the nanocarrier acetal-PEG-PCCL via ionic interaction to form a polymer, which spontaneously formed spherical micelles. The cytotoxicity and cellular uptake of the micelles are superior to free DOX and exhibit mitochondrial targeting and passive tumor targeting, indicating that they have potential prospects.

Precisely targeted drug delivery by mesenchymal stem cells-based biomimetic liposomes to cerebral ischemia-reperfusion injured hemisphere.

The precise and targeted delivery of therapeutic agents to the lesion sites remains a major challenge in treating brain diseases represented by ischemic stroke. Herein, we modified liposomes with mesenchymal stem cells (MSC) membrane to construct biomimetic liposomes, termed MSCsome. MSCsome (115.99 ± 4.03 nm) exhibited concentrated accumulation in the cerebral infarcted hemisphere of mice with cerebral ischemia-reperfusion injury, while showing uniform distribution in the two cerebral hemispheres of normal mice. Moreover, MSCsome exhibited high colocalization with damaged nerve cells in the infarcted hemisphere, highlighting its advantageous precise targeting capabilities over liposomes at both the tissue and cellular levels. Leveraging its superior targeting properties, MSCsome effectively delivered Dl-3-n-butylphthalide (NBP) to the injured hemisphere, making a single-dose (15 mg/kg) intravenous injection of NBP-encapsulated MSCsome facilitate the recovery of motor functions in model mice by improving the damaged microenvironment and suppressing neuroinflammation. This study underscores that the modification of the MSC membrane notably enhances the capacity of liposomes for precisely targeting the injured hemisphere, which is particularly crucial in treating cerebral ischemia-reperfusion injury.

ABCB1 gene polymorphisms, ABCB1 haplotypes and ABCG2 c.421c > A are determinants of inter-subject variability in rosuvastatin pharmacokinetics.

A randomized cross-over pharmacokinetic study of rosuvastatin calcium (single dose: 5 mg, 10 mg and 20 mg; multiple doses: 10mg once daily for 7 days) was conducted in 12 healthy Chinese volunteers. Plasma concentrations of rosuvastatin were determined by an LC-ESI-MS-MS method. Single-nucleotide polymorphisms (SNPs) in ABCB1, ABCG2, SLCOB1, CYP2C9 and CYP3A5 were determined by TaqMan (MGB) genotyping assay. An impact of the aforementioned SNPs on steady state pharmacokinetic parameters [average steady state concentration (Cav,ss) and area under the plasma concentration versus time curve during the dosing interval at steady state (AUCss)], dose-normalized (based on 5 mg) pharmacokinetic parameters of single-dose rosuvastatin were further analyzed. Rosuvastatin exhibited linear pharmacokinetics and great inter-subject variability. Cav,ss, AUCss and dose-normalized peak plasma concentration (Cmax) and AUC(0-infinity) of single-dose rosuvastatin were significantly related with ABCB1 C1236T, G2677T/A and C3435T polymorphisms and ABCB1 haplotypes. Compared to homozygous wild type and heterozygous mutation gene carriers, subjects carrying the variant ABCB1 1236TT, 2677 non-G or 3435TT genotype had higher Cav,ss, AUCss, Cmax and AUC(0-infinity) (p < 0.05). ABCB1 haplotype (1236TT-2677TT-3435TT) had significant influence on dose-normalized pharmacokinetics of single-dose rosuvastatin. ABCB1 haplotype (1236TT-2677TT-3435TT) carriers (n = 12) had obvious higher Cmax (11.16 +/- 3.10 microg x L(-1) vs 8.35 +/- 3.31 microg x L(-1), p < 0.05) and AUC(0-infinity) (86.61 +/- 24.32 microg x h x L(-1) vs 62.60 +/- 26.19 microg x h x L(-1), p < 0.05) compared to non-1236TT-2677TT-3435TT carriers (n = 24). ABCG2 c.421C > A had a significant impact on rosuvastatin pharmacokinetics. Homozygotes (AA) carriers had obvious higher Cmax (12.20 +/- 4.09 microg x L(-1) vs 8.70 +/- 3.09 microg x L(-1), p < 0.05) and AUC(0-infinity) (98.74 +/- 25.36 microg x h x L(-1) vs 64.97 +/- 24.90 microg x h x L(-1), p < 0.05) values compared to heterozygotes (CA) and homozygotes (CC) carriers. There were no significant effects on single-dose and steady-state pharmacokinetics of rosuvastatin by CYP2C9*3 (1075A > C), CYP3A5*3 g.6986A > G, ABCG2 c.34G > A, SLCO1B1 c.521 T > C, c.388 A > G, g.11187 G > A, c.571 T > C and c.597 C > T. In addition, no difference in rosuvastatin pharmacokinetics was observed among subjects of different genders. We conclude that ABCB1 C1236T, G2677T/A and C3435T polymorphism, ABCB1 haplotypes and ABCG2 c.421C > A are determinants of inter-subject variability in rosuvastatin pharmacokinetics in healthy Chinese volunteers, and potentially affect the efficacy and toxicity of statin therapy.

Correction: Yang et al. Construction and Evaluation of Chitosan-Based Nanoparticles for Oral Administration of Exenatide in Type 2 Diabetic Rats. Polymers 2022, 14, 2181.

The authors wish to make the following corrections to this paper [...].

Construction and Evaluation of Chitosan-Based Nanoparticles for Oral Administration of Exenatide in Type 2 Diabetic Rats.

Oral delivery of therapeutic peptides has been a daunting challenge due to poor transport across the tight junctions and susceptibility to enzymatic degradation in the gastrointestinal tract. Numerous advancement in nanomedicine has been made for the effective delivery of protein and peptide. Owing to the superior performance of chitosan in opening intercellular tight junctions of epithelium and excellent mucoadhesive properties, chitosan-based nanocarriers have recently garnered considerable attention, which was formulated in this paper to orally deliver the GLP-1 drug (Exenatide). Against this backdrop, we used chitosan (CS) polymers to encapsulate the exenatide, sodium tripolyphosphate (TPP) as the cross-linking agent and coated the exterior with sodium alginate (ALG) to impart the stability in an acidic environment. The chitosan/alginate nanoparticles (CS-TPP-ALG) functioned as a protective exenatide carrier, realized efficient cellular uptake and controlled release, leading to a steady hypoglycemic effect and a good oral bioavailability in vivo. Trimethyl chitosan (TMC), a chitosan derivative with stronger positive electrical properties was additionally selected as a substitute for chitosan to construct the TMC-TPP-ALG nanoparticle, and its oral peptide delivery capacity was explored in terms of both characterization and pharmacodynamics studies. Overall, our study demonstrated that functional chitosan/alginate nanoparticles can protect proteins from enzymatic degradation and enhance oral absorption, which presents important research value and application prospects.

Recent Progress in the Design and Medical Application of In Situ Self-Assembled Polypeptide Materials.

Inspired by molecular self-assembly, which is ubiquitous in natural environments and biological systems, self-assembled peptides have become a research hotspot in the biomedical field due to their inherent biocompatibility and biodegradability, properties that are afforded by the amide linkages forming the peptide backbone. This review summarizes the biological advantages, principles, and design strategies of self-assembled polypeptide systems. We then focus on the latest advances in in situ self-assembly of polypeptides in medical applications, such as oncotherapy, materials science, regenerative medicine, and drug delivery, and then briefly discuss their potential challenges in clinical treatment.

NK cells are migrated and indispensable in the anti-tumor activity induced by CCL27 gene therapy.

Natural killer (NK) cells have been demonstrated could play an important role in the treatment of a number of tumors in mice. In the present study, chemokine CCL27, which be considered only selectively chemoattracts cutaneous lymphocyte antigen positive memory T cells and Langerhans cells, firstly demonstrated that it could induce the accumulation of NK cells into tumor by the intratumoral injection of CCL27-encoding fiber-mutant vector, AdRGD-CCL27. Experiments using spleen cell fractionation and RT-PCR showed CCL27 receptor, mCCR10, was strongly expressed in NK cells, suggesting the accumulation of NK cells in tumor was attributed to chemoattractant activity of CCL27 itself. Moreover, the combination of AdRGD-CCL27 and AdRGD-IL-12 induced the synergistic anti-tumor activity via NK-dependent manner and induced more NK cells infiltration into tumor nodule than that induced by AdRGD-CCL27 alone or AdRGD-IL-12 alone.

Liposome-based intracellular kinetics of doxorubicin in K562/DOX cells.

Liposomes can improve the intracellular concentration of cytotoxic drugs, and are regarded as a possible pharmacological approach to overcome drug resistance. The kinetic analysis of subcellular drug uptake and efflux helps to elucidate the resistance mechanism which is associated with the ATP-dependent membrane transporter P-glycoprotein (P-gp). However, there are only few reports about the intracellular kinetics of liposomes. In this work, the kinetics of drug uptake and active efflux of doxorubicin (DOX) encapsulated in liposomes in both intact cells and nuclei were studied using P-gp expressing K562/DOX cells. The results show that liposomes enhanced drug accumulation in intact cells and nuclei, and improved DOX retention in nuclei after withdrawal. Furthermore, the nuclei levels of liposomal drug rose slowly and reached a plateau after 2 h incubation, whereas the free drug reached the plateau in 15 min, suggesting that it takes time for the liposomes to get from the cytoplasm to the nuclei. Our results demonstrated that liposomes not only increase DOX levels allocated to nuclei but also extended retention in the nuclei of resistant cells.

[Effect of nano-liposome sustained elemene in inducing cell apoptosis of C6 glioma].

OBJECTIVE: To study the effect of nano-liposome sustained elemene in inducing cell apoptosis of C6 glioma and to explore its influence on the expression of caspase-3 gene. METHODS: C6 glioma cells were cultured in medium with the same amount of nano-liposome sustained elemene and common elemene respectively, also in blank medium for control. The status of cell apoptosis was determined by flow cytometry at 0, 48 h and 72 h, and the expression of Caspase-3 protein was measured simultaneously by immunohistochemistry assay. RESULTS: Marked apoptosis presented in cells cultured in the medium with nano-liposome sustained elemene or common elemene at 48 h and 72 h, with the apoptotic rate significantly higher than that in the control. At the same time, Caspase-3 protein expression raised significantly in cells cultured in medium with either kinds of elemene, showing significant difference when compared with that in the control. CONCLUSION: Elemene has significant apoptosis promoting and Caspase-3 protein expression inducing effect on C6 glioma cells, which could be facilitated by nano-liposome bearing.

[Effects of brucea javanica oil on expression of vascular endothelial growth factor in A549 cell line].

OBJECTIVE: To study the effects of brucea javanica oil on the expression of vascular endothelial growth factor (VEGF) in A549 cell line. METHOD: A549 cells were incubated with different concentrations of brucea javanica oil (0.5, 1.25, 2.5, 5 g x L(-1) for 48 h respectively. VEGF level in supernatant was determined by VEGF ELISA kits and mRNA expression of VEGF was evaluated by RT-PCR. PMN in health volunteers was treated as control groups. RESULT: Supernatant VEGF protein and mRNA expression were significantly elevated in A549 cells compared with the mononuclear cells (120.73 vs 21.21, P < 0.05). Brucea javanica oil (2.5 g x L(-1)) could reduced supernatant VEGF protein in A549 cells (20.30 vs 120.73, P < 0.05), but had no effect on the expression of VEGF mRNA (1.0230 vs 0.9573). It was found that brucea javanica oil (5 g x L(-1)) significantly reduced VEGF mRNA expression (0.4682 vs 0.9573, P < 0.05). CONCLUSION: Brucea javanica oil can depress the VEGF mRNA expression and secretion in A549 cells, which may be one of the mechanisms of its antitumor effect.

Pharmacokinetics and bioequivalence of ranitidine and bismuth derived from two compound preparations.

AIM: To evaluate the bioequivalence of ranitidine and bismuth derived from two compound preparations. METHODS: The bioavailability was measured in 20 healthy male Chinese volunteers following a single oral dose (equivalent to 200 mg of ranitidine and 220 mg of bismuth) of the test or reference products in the fasting state. Then blood samples were collected for 24 h. Plasma concentrations of ranitidine and bismuth were analyzed by high-performance liquid chromatography and inductively coupled plasma-mass spectrometry (ICP-MS), respectively. The non-compartmental method was used for pharmacokinetic analysis. Log-transformed C(max), AUC( (0-t) ) and AUC( (0-infinity) ) were tested for bioequivalence using ANOVA and Schuirmann two-one sided t-test. T(max) was analyzed by Wilcoxon's test. RESULTS: Various pharmacokinetic parameters of ranitidine derived from the two compound preparations, including C(max), AUC( (0-t)), AUC( (0-infinity)), T(max) and T((1/2)), were nearly consistent with previous observations. These parameters derived from test and reference drug were as follows: C(max) (0.67 +/- 0.21 vs 0.68 +/-0.22 mg/L), AUC( (0-t) ) (3.1 +/- 0.6 vs 3.0 +/- 0.7 mg/L per hour), AUC( (0-infinity) ) (3.3 +/- 0.6 vs 3.2 +/- 0.8 mg/L per hour), T(max) (2.3 +/- 0.9 vs 2.1 +/- 0.9 h) and T((1/2)) (2.8 +/- 0.3 vs 3.1 +/- 0.4 h). In addition, double-peak absorption profiles of ranitidine were found in some Chinese volunteers. For bismuth, those parameters derived from test and reference drug were as follows: C(max) (11.80 +/- 7.36 vs 11.40 +/- 6.55 microg/L), AUC( (0-t) ) (46.65 +/- 16.97 vs 47.03 +/- 21.49 microg/L per hour), T(max) (0.50 +/- 0.20 vs 0.50 +/- 0.20 h) and T((1/2)) (10.2 +/- 2.3 vs 13.0 +/- 6.9 h). Ninety percent of confidence intervals for the test/reference ratio of C(max), AUC( (0-t) ) and AUC( (0-infinity) ) derived from both ranitidine and bismuth were found within the bioequivalence acceptable range of 80%-125%. No significant difference was found in T(max) derived from both ranitidine and bismuth. CONCLUSION: The two compound preparations are bioequivalent and may be prescribed interchangeably.

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.

[Clinical significance of CD4+CD25+ T cells in peripheral blood of patients in systemic lupus erythematosus].

OBJECTIVE: To investigate the expressions of C(4)D(+)CD(25)(+) T cells in the peripheral blood of patients with systemic lupus erythematosus (SLE) and to identify the relationship between the levels of CD(4)(+)CD(25)(+) T cells and the disease activity and progression of SLE. METHODS: Fifty-three SLE patients were enrolled in the study. Flow-cytometric assay was employed for detection of CD(4)(+)CD(25)(+) T cells and CD(4)(+)CD(25)(bright) T cells were defined according to fluorescence intensity of CD(25) expression exceeding 100. Meanwhile, correlation analysis was performed between their expression and the scores of SLE disease active index (SLEDAI), C(3), dsDNA and antinuclear antibody titles. RESULTS: The levels of peripheral blood CD(4)(+)CD(25)(+) T cells in SLE were (7.84 +/- 1.85)%, which were significantly lower than those in a group of healthy control [(9.18 +/- 2.01)%, P < 0.05]. The levels of CD(4)(+)CD(25)(+) T cells in a group of active SLE [(6.72 +/- 1.16)%] were higher than those in a group of stable SLE [(8.57 +/- 1.91)%, P < 0.01]. There was no difference between the active and stable groups of SLE in peripheral blood CD(4)(+)CD(25)(bright) T cells [(0.85 +/- 0.24)% vs (0.91 +/- 0.25)%, P = 0.686], but they were significantly lower than those in the group of healthy controls [(1.43 +/- 1.08)%, P < 0.01]. With the reduction of the SLEDAI scores in SLE patients after relevant treatment, the levels of peripheral blood CD(4)(+)CD(25)(bright) T cells did not change. No correlation was found between the levels of CD(4)(+)CD(25)(bright) T cells and SLEDAI scores, antinuclear antibody titles, dsDNA and C(3), respectively (rho = -0.188, P = 0.178; rho = -0.216, P = 0.121; rho = 0.082, P = 0.560; rho = 0.010, P = 0.944). CONCLUSION: The reduction of CD(4)(+)CD(25)(+) T cells in peripheral blood may participate in the pathogenesis of SLE.

[Intervention of maiwei dihuang oral liquid on hormonotherapy in treating active systemic lupus erythematosus].

OBJECTIVE: To observe the intervention of Maiwei Dihuang Oral Liquid (MDOL) on hormonotherapy in treating active systemic lupus erythematosus (SLE). METHODS: Sixty SLE patients in active stage were randomly and equally allocated into two groups, and administered with prednisone, which was medicated in initial dose of 0.5-1 mg/kg, and with the dose being reduced conditionally 6-8 weeks. To the 30 patients in the treated group 10 ml MDOL twice daily was given additionally. The therapeutic course was 3 months. RESULTS: The therapeutic effect in the treated group was better than that in the control group (P < 0.05). Systemic lupus erythematosus disease activity index (SLEDAI) was significantly improved in both groups (P < 0.01), but was superior in the treated group (P < 0.05). The dose of prednisone used was significantly reduced (P < 0.01), and the scores of Yin-deficiency fire-flourishing syndrome were obviously decreased (P < 0.01) in the treated group while in the control group, these indexes were unchanged (P > 0.05), the difference between the two groups was significant (P < 0.01). The occurrence of adverse reaction was significantly lower in the treated group than that in the control group (P < 0.05). CONCLUSION: MDOL can obviously improve the effect of hormonotherapy in SLE, it has advantages in reducing the dosage used and antagonizing the adverse reactions of glucocorticoid.

Effect of receptor solution specific conductivity on iontophoresis of tetracaine hydrochloride.

AIM: To examine the quantitative relationship between solution specific conductivity and the permeability of tetracaine HCl, and to investigate the effect of receptor solution specific conductivity on the iontophoretic transport. METHODS: An in vitro study was carried out to determine the iontophoretic permeability of tetracaine hydrochloride through rat skin. Iontophoretic flux of tetracaine hydrochloride through excised rat skin was determined using Valia-Chien two-chamber diffusion cells with a constant d.c. current and Ag/AgCl electrodes. The specific conductivities of donor and receptor solution were also measured. RESULTS: Iontophoretic flux of tetracaine hydrochloride increased with a decrease of anion (chloride ion) concentration in receptor. And the iontophoretic permeability (ER, ER is the enhancement ratio, and ER = iontophoretic flux/passive flux) for tetracaine hydrochloride was directly related to the conductivity of receptor solution when other conditions were held constant. Linear regressions confirmed that ER was related to inverse of overall specific conductivity of donor and receptor solution [1/(ks.d + ks.r), ks.d and ks.r are the specific conductivity of donor and receptor solution]. CONCLUSION: The results suggest that specific conductivity of receptor solution may be a important factor for the iontophoretic permeability of a solute.

Nanocarrier improves the bioavailability, stability and antitumor activity of camptothecin.

Camptothecin (CPT) nanosuspension was prepared by anti-solvent precipitation with TPGS as stabilizer to improve the solubility, stability and antitumor activity of CPT. And an increased solubility, stability and dissolution rate was achieved after nanosuspension being prepared. While, enhanced intracellular accumulation and cellular cytotoxicity was also observed for CPT nanosuspension than that of CPT solution.In addition, nanosuspension could increase bioavailability and intratumor accumulation of CPT in vivo after intravenous administration, and then produced a much higher antitumor effect and biocompatibility than that of CPT solution. Meanwhile, an enhanced cellular CPT uptake in hypoxic or acid conditions could also be observed for nanosuspension. As a result, nanosuspension represents a potentially feasible formation for insoluble drug in antitumor research.

Overcoming drug resistance of MCF-7/ADR cells by altering intracellular distribution of doxorubicin via MVP knockdown with a novel siRNA polyamidoamine-hyaluronic acid complex.

Drug resistance is one of the critical reasons leading to failure in chemotherapy. Enormous studies have been focused on increasing intracellular drug accumulation through inhibiting P-glycoprotein (Pgp). Meanwhile, we found that major vault protein (MVP) may be also involved in drug resistance of human breast cancer MCF-7/ADR cells by transporting doxorubicin (DOX) from the action target (i.e. nucleus) to cytoplasma. Herein polyamidoamine (PAMAM) dendrimers was functionalized by a polysaccharide hyaluronic acid (HA) to effectively deliver DOX as well as MVP targeted small-interfering RNA (MVP-siRNA) to down regulate MVP expression and improve DOX chemotherapy in MCF-7/ADR cells. In comparison with DOX solution (IC50=48.5 µM), an enhanced cytotoxicity could be observed for DOX PAMAM-HA (IC50=11.3 µM) as well as enhanced tumor target, higher intracellular accumulation, increased blood circulating time and less in vivo toxicity. Furthermore, codelivery of siRNA and DOX by PAMAM-HA exhibited satisfactory gene silencing effect as well as enhanced stability and efficient intracellular delivery of siRNA, which allowed DOX access to nucleus and induced subsequent much more cytotoxicity than siRNA absent case as a result of MVP knockdown. This observation highlights a promising application of novel nanocarrier PAMAM-HA, which could co-deliver anticancer drug and siRNA, in reversing drug resistance by altering intracellular drug distribution.

A novel camptothecin derivative incorporated in nano-carrier induced distinguished improvement in solubility, stability and anti-tumor activity both in vitro and in vivo.

PURPOSE: An oil/water nanoemulsion was developed in the present study to enhance the solubility, stability and anti-tumor activity of a novel 10-methoxy-9-nitrocamptothecin (MONCPT). MATERIALS AND METHODS: MONCPT nanoemulsion was prepared using Lipoid E80 and cremophor EL as main emulsifiers by microfluidization. The droplet size of the nanoemulsion was measured by dynamic light scattering. In vitro drug release was monitored by membrane dialysis. Kinetics of MONCPT transformed into carboxylic salt was performed in phosphate buffer at different pH. Hemolysis of MONCPT nanoemulsion was conducted in rabbit erythrocytes. Solubilization character of MONCPT in nanoemulsion was experimented using Nile red as a solvatochromic probe. In vitro cytotoxicity of the nanoemulsion was measured in A549 and S180 cells using Sulforhodamine B protein stain method, and suppression rate of tumor growth was investigated in S180-bearing mice. The cell cycle effects of MONCPT nanoemulsion on S180 cells were analyzed by flow cytometry. Distribution of the nanoemulsion in A549 cells and S180-bearing mice were also investigated by fluorescence image. RESULTS: MONCPT is incorporated in the nanoemulsion in form of lactone with concentration of 489 microg/ml, more than 200 folds higher than that in water. Experiments using Nile red as a solvatochromic probe indicated that more MONCPT might be located in the interfacial surfactant layer of the nanoemulsion than that in discrete oil droplet or continuous aqueous phase. Nanoemulsion could release MONCPT in a sustained way, and it was further shown to notably postpone the hydrolysis of MONCPT with longer hydrolysis half-life time (11.38 h) in nanoemulsion at pH 7.4 than that of MONCPT solution (4.03 h). No obvious hemolysis was caused by MOCPT nanoemulsion in rabbit erythrocytes. MONCPT nanoemulsion showed a marked increase in cytotoxic activity, 23.6 folds and 28.6 folds in S180 cells and A549 cells respectively via arresting the cell at G2 phase, compared to that induced by MONCPT injection. It correlated well to the in vivo anti-tumor activity of MONCPT nanoemulsion with suppression rate of 93.6%, while that of MONCPT injection was only 24.2% at the same dosage. Moreover, nanoemulsion exhibited enhanced capability of delivering drug into malignant cell's nucleus in vitro and induced drug accumulation in tumor in S180-bearing mice using in vivo imaging. CONCLUSION: The nanoemulsion prepared exhibited an improved MONCPT solubility, stability and anti-tumor activity, providing a promising carrier for cancer chemotherapy using MONCPT.

Quantitative determination of domperidone in human plasma by ultraperformance liquid chromatography with electrospray ionization tandem mass spectrometry.

A simple and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for determining domperidone in human plasma. The analyte and internal standard (IS; mosapride) were isolated from plasma samples by protein precipitation with methanol (containing 0.1% formic acid). The chromatographic separation was performed on an Xterra MS C(18) Column (2.1 x 150 mm, 5.0 microm) with a gradient programme mobile phase consisting of 0.1% formic acid and acetonitrile at a flow rate of 0.30 mL/min. The total run time was 4.0 min. The analyses were carried out by multiple reaction monitoring using the parent-to-daughter combinations m/z 426 --> 175 and m/z 422 --> 198 (IS). The areas of peaks from the analyte and IS were used for quantification of domperidone. The method was validated according to the FDA guidelines on bioanalytical method validation. Validation results indicated that the lower limit of quantification was 0.2 ng/mL, and the assay exhibited a linear range of 0.2-60.0 ng/mL and gave a correlation coefficient (r(2)) of 0.999 or better. Quality control samples (0.4, 0.8, 15 and 50 ng/mL) in six replicates from three different analytical runs demonstrated an intra-assay precision (RSD) 4.43-6.26%, an inter-assay precision 5.25-7.45% and an overall accuracy (relative error) of <6.92%. The method can be applied to pharmacokinetic and bioequivalence studies of domperidone.