A novel macrophage-mediated biomimetic delivery system with NIR-triggered release for prostate cancer therapy.

BACKGROUND: Macrophages with tumor-tropic migratory properties can serve as a cellular carrier to enhance the efficacy of anti neoplastic agents. However, limited drug loading (DL) and insufficient drug release at the tumor site remain the main obstacles in developing macrophage-based delivery systems. In this study, we constructed a biomimetic delivery system (BDS) by loading doxorubicin (DOX)-loaded reduced graphene oxide (rGO) into a mouse macrophage-like cell line (RAW264.7), hoping that the newly constructed BDS could perfectly combine the tumor-tropic ability of macrophages and the photothermal property of rGO. RESULTS: At the same DOX concentration, the macrophages could absorb more DOX/PEG-BPEI-rGO than free DOX. The tumor-tropic capacity of RAW264.7 cells towards RM-1 mouse prostate cancer cells did not undergo significant change after drug loading in vitro and in vivo. PEG-BPEI-rGO encapsulated in the macrophages could effectively convert the absorbed near-infrared light into heat energy, causing rapid release of DOX. The BDS showed excellent anti-tumor efficacy in vivo. CONCLUSIONS: The BDS that we developed in this study had the following characteristic features: active targeting of tumor cells, stimuli-release triggered by near-infrared laser (NIR), and effective combination of chemotherapy and photothermotherapy. Using the photothermal effect produced by PEG-BPEI-rGO and DOX released from the macrophages upon NIR irradiation, MAs-DOX/PEG-BPEI-rGO exhibited a significant inhibitory effect on tumor growth.

Redox-Sensitive Micelles Based on O,N-Hydroxyethyl Chitosan-Octylamine Conjugates for Triggered Intracellular Delivery of Paclitaxel.

A redox-sensitive micellar system constructed from an O,N-hydroxyethyl chitosan-octylamine (HECS-ss-OA) conjugate with disulfide linkages between the hydrophobic alkyl chains and hydrophilic chitosan backbone was synthesized for triggered intracellular delivery of hydrophobic paclitaxel (PTX). In aqueous environments, conjugates formed micelles with high PTX loading (>30%). Mechanistically, the sensitivity of HECS-ss-OA micelles to reducing environments was investigated using the parameters of in vitro release and particle size. Intracellular release of nile red fluorescence alongside cytotoxicity studies further confirmed the potency of redox-sensitive micelles for intracellular drug delivery compared with redox-insensitive micelles. Additionally, an in vivo study confirmed the efficacy of PTX-loaded micelles in tumor-bearing mice with superior antitumor efficacy and diminished systemic toxicity when compared with the redox-insensitive micelles and a PTX solution. These results demonstrate the potential of redox-sensitive HECS-ss-OA micelles for intracellular trafficking of lipophilic anticancer drugs.

Ethosomes for skin delivery of ropivacaine: preparation, characterization and ex vivo penetration properties.

Ropivacaine, a novel long-acting local anesthetic, has been proved to own superior advantage. However, Naropin® Injection, the applied form in clinic, can cause patient non-convenience. The purpose of this study was to formulate ropivacaine (RPV) in ethosomes and evaluate the potential of ethosome formulation in delivering RPV transdermally. The RPV-loaded ethosomes were prepared with thin-film dispersion technique and the formulation was characterized in terms of size, zeta potential, differential scanning calorimetry (DSC) analysis and X-ray diffraction (XRD) study. The results showed that the optimized RPV-ethosomes displayed a typical lipid bilayer structure with a narrow size distribution of 73.86 ± 2.40 nm and drug loading of 8.27 ± 0.37%, EE of 68.92 ± 0.29%. The results of DSC and XRD study indicated that RPV was in amorphous state when encapsulated into ethosomes. Furthermore, the results of ex vivo permeation study proved that RPV-ethosomes could promote the permeability in a high-efficient, rapid way (349.0 ± 11.5 µg cm(-2) at 12 h and 178.8 ± 7.1 µg cm(-2) at 0.5 h). The outcomes of histopathology study forecasted that the interaction between ethosomes and skin could loosen the tight conjugation of corneocyte layers and weaken the permeation barrier. In conclusion, RPV-ethosomes could be a promising delivery system to encapsulate RPV and deliver RPV for transdermal administration.

Modification of sodium aescinate into a safer, more stable and effective water-soluble drug by liposome-encapsulation: an in vitro and in vivo study.

Sodium aescinate (SA) is often used for intravenous (IV) injection owing to its anti-inflammatory, anti-exudative, increasing venous tension, improving blood circulation and reducing swelling activities. However, the clinical application of SA is limited by strong irritation, short half-life and low bioavailability. To overcome these defects, we intended to modify SA by encapsualing it with liposomes . SA was mixed with a proper amount of phospholipid and lyophilized to prepare the liposome of sodium aescinate for injection (SA-Lip-I). Its physical properties, cumulative release and dilution stability were evaluated in vitro. Its pharmacodynamic characteristics were evaluated. Safety of SA-Lip-I was evaluated in terms of hemolysis, IV irritation and acute toxicity. The mean particle size of SA-Lip-I was 117.33±0.95 nm, polydispersity index (PDI) was 0.140±0.017, Zeta potential was -30.34±0.23 mv, The cumulative release of SA-Lip at 12 h was more than 80%, which met the release requirements of nanoparticles. SA-Lip-I was well stable in the four mediators and met the clinical medication requirements. In addition, SA-Lip-I had better efficacy than the SA-I and has a significant difference. Furthermore, SA-Lip-I did not induce hemolysis at 37°C, and produced by far milder venous irritation as compared with SA-I. In addition, LD50 of SA-Lip-I was 2.12 fold that of the commercial SA-I, with no obvious side effects.The modified SA-Lip-I is a promising preparation which can reduce the irritation and toxic side effects, improve the treatment effect to a certain extent, but greatly alleviate pain of the patient during treatment, achieving the optimal curative effect.

Modified percutaneous transhepatic variceal embolization with 2-octylcyanoacrylate for bleeding gastric varices: long-term follow-up outcomes.

OBJECTIVE: The objective of our study was to evaluate the long-term efficacy and safety of a modified percutaneous transhepatic variceal embolization procedure with 2-octylcyanoacrylate (2-OCA) in the treatment of gastric variceal bleeding. MATERIALS AND METHODS: From January 2003 to December 2008, 71 patients with a history of gastric variceal bleeding underwent modified percutaneous transhepatic variceal embolization with 2-OCA in our hospital: 12 patients with acute gastric variceal bleeding underwent emergency obliteration and the remaining 59 patients with recent variceal bleeding underwent modified percutaneous transhepatic variceal embolization as a secondary prophylaxis. The initial hemostasis rate, rebleeding rate, survival rate, and complications were evaluated. RESULTS: Complete obliteration--that is, all the gastric varices and their feeding veins were obliterated--was achieved after the percutaneous transhepatic variceal embolization procedure in 67 patients (94.4%). Acute variceal bleeding was arrested after the procedure in all 12 patients (100%). The mean follow-up period was 24.2 ± 12.4 (SD) months (range, 6-62 months). During the follow-up period, the cumulative probability of remaining free of gastric variceal rebleeding in patients with complete obliteration was 100%, 88.2%, and 88.2% at 1, 3, and 5 years after the procedure, respectively. Follow-up CT revealed that the modified percutaneous transhepatic variceal embolization procedure with 2-OCA can achieve long-lasting obliteration in the entire varices and in all the feeding veins. The cumulative survival rates at 1, 3, and 5 years after the procedure were 96.9%, 68.9%, and 53.7%. No severe complications occurred after the procedure. CONCLUSION: The modified percutaneous transhepatic variceal embolization with 2-OCA is considered to be an effective and safe method for the extensive and permanent obliteration of both gastric varices and their feeding veins.

In vitro controlled release of sodium ferulate from Compritol 888 ATO-based matrix tablets.

A controlled release matrix formulation for freely water-soluble drug of sodium ferulate (SF) was designed and developed to achieve a 24h release profile. Using Compritol 888 ATO as an inert matrix-forming agent to control the release of SF, formulation granules containing the physical mixtures or solid dispersions were investigated. The matrix tablets for these formulations were prepared by direct compression and their in vitro release tests were carried out. The solid dispersion based tablets were found to be more effective than those compressed from physical mixtures in retarding the release of SF. Drug release from the matrix tablets containing physical mixtures nearly completed within 12h, while that from the solid dispersion formulations lasted for over 24h. Images of the tablet surface and cross-section were characterized by scanning electron microscopy to show the formed pores and channels in the matrices. These might provide the release pathway for the inner embedded drugs. Drug released fast from the matrix tablets with the release-enhancer of lactose. The addition of surfactants was also found to increase the release rate of SF effectively. Moreover, the co-mixing of polyethylene glycol 6000 (PEG 6000) in the waxy matrices played a meaningful role in controlling the drug release for 24h. The drug release from the novel formulation might be attributed to the diffusion-controlled mechanism.

In vitro and in vivo study of Baicalin-loaded mixed micelles for oral delivery.

The aim of this work was to research the potential functions and the mechanism of absorption of the baicalin (BC)-loaded micelle system that contained Pluronic P123 copolymer (P123) and sodium taurocholate (ST) as carrier materials via oral delivery. Based on the numerous advantages of oral administration, such as cost-effectiveness, flexible and accommodated dosing regimen, and improved compliance for patients, the ST-P123-MMs system would be evaluated as oral delivery vehicle of BC. In this study, X-ray powder diffractometer analysis confirmed the phase change of BC after being incorporated in mixed micelles. The release study in simulated gastric fluid/simulated intestinal fluid exhibited that BC-loaded ST-P123-MMs presented a sustained drug release behavior. Compared with coumarin-6 solution, higher cellar uptake efficiency was achieved for coumarin-6 loaded ST-P123-MMs towards Caco-2 cell lines. The in situ perfusion test in rat indicated that the absorption of BC-loaded ST-P123-MMs in intestinal tract was stronger than BC solution. After oral administration, the Cmax and AUC of BC-loaded ST-P123-MMs were 1.77 times and 1.54 times as high as those of BC suspension in rat, respectively. Promisingly, the formulated BC exhibited a prolonged circulation time with the oral bioavailability increased to 1.54-fold compared with the control group. These results all suggested that P123 and ST mixed micelles could serve as a promising approach to oral administration of BC.

Smart nanoparticles with a detachable outer shell for maximized synergistic antitumor efficacy of therapeutics with varying physicochemical properties.

Co-delivery systems capable of transporting hydrophobic chemotherapeutics and hydrophilic siRNA to the same cell population with simultaneous burst release of both drugs to maximize synergistic anticancer efficacy remains elusive. In this light, a multifunctional nanoparticle (HA-PSR) consisting of a redox-sensitive core and detachable crosslinked hyaluronic acid (HA) shell was developed. Octyl modified PEI containing disulfide linkages (PSR) were synthesized as the core materials for co-encapsulation of chemotherapeutics and siRNA, while a HAase-sensitive thiolated HA (HA-SH) was collaboratively assembled to the anionic shell for CD44-mediated active targeting along with enhanced and detachable protection for drug loaded inner cores. Resultantly, HA de-protected redox-sensitive inner cores achieved co-burst release of both cargoes when triggered by glutathione (GSH) rich environments in cytoplasm. Results of in-vivo and in-vitro testing indicated successful co-encapsulation of hydrophobic drugs and hydrophilic siRNA with adjustable ratios. Selective delivery to CD44 overexpressing tumors was achieved through passive and active targeting, followed by HAase-triggered HA de-shielding and GSH-triggered burst release of both cargos. Rapid intracellular trafficking maximized synergistic cytotoxicities of chemotherapeutics and siRNA for remarkable tumor inhibition in a xenograft animal tumor model. Consequently, the HA-PSR nanoparticle holds great potential for combined chemotherapeutics/siRNA treatment in cancer with maximized synergistic antitumor efficacy.

Biological evaluation of PEG modified nanosuspensions based on human serum albumin for tumor targeted delivery of paclitaxel.

Since its approval by the FDA, Abraxane™ has been established as a clinical standard of paclitaxel (PTX)-based therapy against a variety of cancers. Despite success, Abraxane™ is still limited by suboptimal biodistribution, unfavorable pharmacokinetics and chronic toxicities from chloroform used during preparation. Accordingly, a PTX-loaded nanosuspension based on human serum albumin (HSA) with PEG modifiers (PTX-PEG-HSA) has been developed to optimize the in-vivo biodistribution, pharmacokinetics and safety of PTX over traditional PTX-HSA nanosuspensions prepared using the accepted method for Abraxane™. Results of in-vivo pharmacokinetic (PK) studies indicated PTX-PEG-HSA achieved prolonged blood circulation, illustrated by an 8.8-fold and 4.8-fold increase in area-under-the-curve (AUC) of PTX over Taxol® and PTX-HSA, while the mean residence time (MRT) of PTX in PTX-PEG-HSA was increased by 3.2-fold and 1.5-fold, respectively. HSA mediated active targeting further suppressed non-specific distribution of PTX to normal tissues, which permitted enhanced antitumor efficacy in S180 mice over Taxol® and PTX-HSA. Safety of intravenously administered PTX-PEG-HSA was confirmed through lower hemolytic activity, a 2.2-fold and 1.2-fold increase in LD50 (113.4 mg/kg) over Taxol® and PTX-HSA alongside the absence of local venous irritation. Studies herein suggest the therapeutic and clinical applicability of PTX-PEG-HSA for tumor specific therapy.

Newly designed "pieced" stent in a rabbit model of benign esophageal stricture.

AIM: To investigate a newly designed stent and its dilatation effect in a rabbit model of benign esophageal stricture. METHODS: Thirty-four New Zealand white rabbits underwent a corrosive injury in the middle esophagus for esophageal stricture formation. Thirty rabbits with a successful formation of esophageal strictures were randomly allocated into two groups. The control group (n = 15) was implanted with a conventional stent, and the study group (n = 15) was implanted with a detachable "pieced" stent. The study stent (30 mm in length, 10 mm in diameter) was composed of three covered metallic pieces connected by surgical suture lines. The stent was collapsed by pulling the suture lines out of the mesh. Two weeks after stricture formation, endoscopic placement of a conventional stent or the new stent was performed. Endoscopic extraction was carried out four weeks later. The extraction rate, ease of extraction, migration, complications, and survival were evaluated. RESULTS: Stent migration occurred in 3/15 (20%) animals in the control group and 2/15 (13%) animals in the study group; the difference between the two groups was not statistically significant. At the end of four weeks, the remaining stents were successfully extracted with the endoscope in 100% (11/11) of the animals in the study group, and 60% (6/10) of the animals in the control group; this difference was statistically significant (P < 0.05). There was no difference in the mean number of follow-up days between the control and study groups (25.33 vs 25.85). Minor bleeding was reported in five cases in the study group and four in the control group. There were no severe complications directly associated with stent implantation or extraction in either of the two groups. CONCLUSION: In this experimental protocol of benign esophageal strictures, the novel "pieced" stent demonstrated a superior removal rate with a similar migration rate compared to a conventional stent.

Fabrication of a composite system combining solid lipid nanoparticles and thermosensitive hydrogel for challenging ophthalmic drug delivery.

The purpose of this study was to explore a composite thermosensitive in situ gelling formulation using the distribution of solid lipid nanoparticles (SLNs) among poloxamer-based hydrogels as a potential carrier for novel ocular drug delivery. SLNs containing the model drug Resina Draconis were prepared using a melt-emulsion ultrasonication method. A central composite design (CCD) was adopted to screen the thermosensitive hydrogel (THG) formulation. After aqueous SLNs were dispersed into the THG matrices, the physicochemical properties of the SLNs were characterized before and after their incorporation into hydrogels. The in vitro corneal penetration experiment, ocular irritant test and transcorneal mechanism across the cornea have been previously described to predict the feasibility for the proposed ophthalmic application. Finally, the optimal THGs consisted of 27.8% (w/v) poloxamer 407 and 3.55% (w/v) poloxamer 188. The particle size of the SLNs remained within the colloidal range. In vitro corneal penetration studies revealed a nearly steady sustained drug release. The hen's egg test-chorioallantoic membrane (HET-CAM) test indicated that all of the tested polymer systems were non-irritant. Coumarin-6 labeled SLNs formulated into THGs displayed a more homogeneous fluorescence with a deeper penetration intensity into the cornea at various times. Taken together, these results suggest that the SLN-based THG system can be used as a potential vehicle for ocular application.

Comparison of modified percutaneous transhepatic variceal embolization and endoscopic cyanoacrylate injection for gastric variceal rebleeding.

AIM: To compare the efficacy of modified percutaneous transhepatic variceal embolization (PTVE) with 2-octyl-cyanoacrylate (2-OCA) and endoscopic variceal obturation (EVO) with an injection of 2-OCA for prophylaxis of gastric variceal rebleeding. METHODS: In this retrospective study, the medical records of liver cirrhosis patients with gastric variceal bleeding who underwent either endoscopic 2-OCA (EVO) or modified PTVE using 2-OCA at Shandong Provincial Hospital from January 2006 to December 2008 were reviewed. Patient demographics, rebleeding rate, survival rate, and complications were compared between the two groups (PTVE and EVO). All results were expressed as mean ± SD, or as a percentage. Quantitative variables were compared by two sample Student t tests, and qualitative variables were compared by the Fisher exact test or the χ² test (with Yates correction) where appropriate. A P value less than 0.05 was considered significant. Statistical computation was performed using SPSS 13.0 software. RESULTS: A total of 77 patients were included; 45 patients who underwent EVO and 32 patients who received PTVE. During the follow-up (19.78 ± 7.70 mo in the EVO group, vs 21.53 ± 8.56 mo in the PTVE group) rebleeding occurred in 17 patients in the EVO group and in 4 patients in the PTVE group (37.78% vs 12.5%, P = 0.028). The cumulative rebleeding-free rate was 75%, 59%, and 49% in 1, 2, and 3 years respectively for EVO, and 93%, 84%, and 84% for PTVE (P = 0.011). Cox analysis was used to identify independent factors that predicted rebleeding after treatment. Variables including age, gender, cause, Child-Pugh classification, size of gastric varices (GV), location of GV, and treatment methods were analyzed. It was revealed that Child-Pugh classification [risk ratio (RR) 2.10, 95%CI: 1.03-4.28, P = 0.040], choice of treatment (RR 0.25, 95%CI: 0.08-0.80, P = 0.019), and size of GV (RR 2.14, 95%CI: 1.07-4.28, P = 0.032) were the independent factors for predicting rebleeding. Follow-up computed tomography revealed that cyanoacrylate was retained in the varices and in the feeding veins of PTVE patients. During the follow-up, eight patients in the EVO group and four patients in the PTVE group died. The cumulative survival rates at 1, 2, and 3 years were 93%, 84%, and 67% respectively in the EVO group, and 97%, 88%, and 74% respectively in the PTVE group. The survival rates were not significantly different between the two groups (P = 0.432). Cox analysis showed that the Child-Pugh classification was the most significant prognostic factor of survival (RR 2.77, 95%CI: 1.12-6.80, P = 0.027). The incidence of complications was similar in both groups. CONCLUSION: With extensive and permanent obliteration of gastric varices and its feeding veins, PTVE with 2-OCA is superior to endoscopic 2-OCA injection for preventing gastric variceal rebleeding.

Degradable gene delivery systems based on Pluronics-modified low-molecular-weight polyethylenimine: preparation, characterization, intracellular trafficking, and cellular distribution.

BACKGROUND: Cationic copolymers consisting of polycations linked to nonionic amphiphilic block polymers have been evaluated as nonviral gene delivery systems, and a large number of different polymers and copolymers of linear, branched, and dendrimeric architectures have been tested in terms of their suitability and efficacy for in vitro and in vivo transfection. However, the discovery of new potent materials still largely relies on empiric approaches rather than a rational design. The authors investigated the relationship between the polymers' structures and their biological performance, including DNA compaction, toxicity, transfection efficiency, and the effect of cellular uptake. METHODS: This article reports the synthesis and characterization of a series of cationic copolymers obtained by grafting polyethyleneimine with nonionic amphiphilic surfactant polyether-Pluronic(®) consisting of hydrophilic ethylene oxide and hydrophobic propylene oxide blocks. Transgene expression, cytotoxicity, localization of plasmids, and cellular uptake of these copolymers were evaluated following in vitro transfection of HeLa cell lines with various individual components of the copolymers. RESULTS: Pluronics can exhibit biological activity including effects on enhancing DNA cellular uptake, nuclear translocation, and gene expression. The Pluronics with a higher hydrophilic-lipophilic balance value lead to homogeneous distribution in the cytoplasm; those with a lower hydrophilic-lipophilic balance value prefer to localize in the nucleus. CONCLUSION: This Pluronic-polyethyleneimine system may be worth exploring as components in the cationic copolymers as the DNA or small interfering RNA/microRNA delivery system in the near future.

A mesoporous silica nanoparticulate/ß-TCP/BG composite drug delivery system for osteoarticular tuberculosis therapy.

A composite scaffold drug delivery system (CS-DDS) for osteoarticular tuberculosis therapy has been prepared by loading bi-component drugs into a mesoporous silica nanoparticles (MSNs)-coated porous ß-TCP scaffold, which was followed by an additional bioactive glass coating. Such a CS-DDS showed high performances in the local and extremely sustained delivery of the bi-component antitubercular drugs and excellent biocompatibility. N(2) sorption isotherms indicated greatly increased surface area of the composites compared to pure ß-TCP scaffold, and the mesopores were around 2.6 nm which were large enough to encapsulate drugs such as isoniazide and rifampicin. The in vitro and in vivo release tests demonstrated extra sustained co-release profiles of rifampicin and isoniazide from such a CS-DDS, and both drug concentrations kept higher than their effective values to kill mycobacterium tuberculosis for as long as 42 days. The hepatic and renal function tests indicated that the CS-DDS had neglectable long-term lesions to liver and kidney.

Second-generation aptamer-conjugated PSMA-targeted delivery system for prostate cancer therapy.

BACKGROUND: miR-15a and miR-16-1 have been identified as tumor suppressor genes in prostate cancer, but their safe and effective delivery to target cells is key to the successful use of this therapeutic strategy. RNA aptamer A10 has been used as a ligand, targeting prostate cancer cells that express prostate-specific membrane antigen (PSMA). Compared with A10, the binding of the second-generation RNA aptamer, A10-3.2, to PSMA is more efficient. METHODS: A10-3.2 was investigated as a PSMA-targeting ligand in the design of a polyamidoamine (PAMAM)-based microRNA (miR-15a and miR-16-1) vector to prostate cancer cells. Using polyethyleneglycol (PEG) as a spacer, PAMAM was conjugated to aptamer (PAMAM-PEG-APT) and used as a vehicle for miRNA target delivery. RESULTS: Luciferase assays of pGL-3 expression against PC3 (PSMA(-)) and LNCaP (PSMA(+)) cells demonstrated that the transfection efficiency of the synthesized DNA/PAMAM-PEG-APT complex was higher than that of the DNA/PAMAM-PEG complex. In addition, cell viability assays of LNCaP (PSMA(+)) cells showed that, with a N/P ratio of 15:1, the IC(50) value of miRNA/PAMAM-PEG-APT was approximately 4.7-fold lower than that of miRNA/PAMAM-PEG. CONCLUSION: This PSMA-targeted system may prove useful in widening the therapeutic window and allow for selective killing of prostate cancer cells.

Strong cellular and humoral immune responses induced by transcutaneous immunization with HBsAg DNA-cationic deformable liposome complex.

Transcutaneous immunization presents a major challenge on account of poor permeability of antigens through the skin barrier. To overcome this limitation, the deformable liposome could be a better method for transcutaneous delivery of these antigens. In this study, hepatitis B surface antigen (HBsAg) plasmid DNA-cationic complex deformable liposome was utilized as a mode for enhanced immunity against the antigen. Deformable liposome was prepared by conventional rotary evaporation method and characterized for various parameters such as vesicles shape and surface morphology, size and size distribution, entrapment efficiency, elasticity and stability. The immune stimulating activity was studied by measuring serum anti-HBsAg titre and cytokines level (interleukin-4 and interferon-gamma) following topical application of liposome in BALB/c mice and results were compared with deformable liposome encapsulated DNA applied topically as well as naked DNA and pure recombinant HBsAg, administered intramuscularly. It was observed that deformable liposome elicited a comparable serum antibody titre and endogenous cytokines levels compared to other vaccinations. The study signifies the potential of deformable liposome as DNA vaccine carriers for effective transcutaneous immunization.