IOP Injection, A Novel Superparamagnetic Iron Oxide Particle MRI Contrast Agent for the Detection of Hepatocellular Carcinoma: A Phase II Clinical Trial.

BACKGROUND: MRI is crucial in diagnosing hepatocellular carcinoma (HCC). Superparamagnetic iron oxide particles (SPIO) are liver-specific contrast agents which enhance lesions in T2 -weighted images. Iron oxide nano-particle m-PEG-silane (IOP) Injection, a newly developed SPIO, showed promising imaging effects and good safety profile in preclinical studies and in phase I clinical trial. PURPOSE: To evaluate the safety and clinical validity of IOP Injection as MRI contrast agent in diagnosing HCC. STUDY TYPE: Prospective. SUBJECTS: A total of 52 subjects (61.6 ± 11.05 years, 45 males/7 females) with suspected HCC. FIELD STRENGTH/SEQUENCE: 1.5 T, T1 -weighted in/opposed phase, T2 *-weighted gradient echo, T2 -weighted fast spin echo, true fast imaging with steady-state free precession. ASSESSMENT: Adverse effects and clinical monitoring were recorded throughout the 5-day study. Two independent readers (M.G.H. with 30 years of experience, S.P.K. with 26 years of experience) made the diagnosis. The diagnostic performance of IOP-enhanced MRI was evaluated with sensitivity and positive predictive value by comparing to the pathology reports from subsequent hepatic resection. The number of lesions with various sizes and degrees of differentiation detected by IOP-enhanced MRI was assessed. The relative change in signal intensities over time was indirectly measured from acquired images. STATISTICAL TESTS: Sensitivity and positive predictive value were used to evaluate the diagnostic performance of IOP-enhanced MRI. Prevalence-adjusted and bias-adjusted 𝜅 coefficient was used to assess the interreader variability. RESULTS: No serious adverse event related to IOP Injection was found. IOP Injection enhanced the lesion-to-liver contrast ratio in T2 *-weighted images by 50.1% ± 4.8%. IOP-enhanced MRI detected HCC with 100% sensitivity by subject and 96% sensitivity by lesion. IOP Injection visualized subtle vascular invasion as filling defect within vessels in true fast imaging with steady-state free precession (TrueFISP) images. DATA CONCLUSION: IOP Injection was safe and efficacious as MRI contrast agent in diagnosing HCC in a limited group of subjects. EVIDENCE LEVEL: 2. TECHNICAL EFFICACY: Stage 2.

pH-Responsive therapeutic solid lipid nanoparticles for reducing P-glycoprotein-mediated drug efflux of multidrug resistant cancer cells.

In this study, a novel pH-responsive cholesterol-PEG adduct-coated solid lipid nanoparticles (C-PEG-SLNs) carrying doxorubicin (DOX) capable of overcoming multidrug resistance (MDR) breast cancer cells is presented. The DOX-loaded SLNs have a mean hydrodynamic diameter of ~100 nm and a low polydispersity index (under 0.20) with a high drug-loading efficiency ranging from 80.8% to 90.6%. The in vitro drug release profiles show that the DOX-loaded SLNs exhibit a pH-controlled drug release behavior with the maximum and minimum unloading percentages of 63.4% at pH 4.7 and 25.2% at pH 7.4, respectively. The DOX-loaded C-PEG-SLNs displayed a superior ability in inhibiting the proliferation of MCF-7/MDR cells. At a DOX concentration of 80 µM, the cell viabilities treated with C-PEG-SLNs were approximately one-third of the group treated with free DOX. The inhibition activity of C-PEG-SLNs could be attributed to the transport of C-PEG to cell membrane, leading to the change of the composition of the cell membrane and thus the inhibition of permeability glycoprotein activity. This hypothesis is supported by the confocal images showing the accumulation of DOX in the nuclei of cancer cells and the localization of C-PEG on the cell membranes. The results of in vivo study further demonstrated that the DOX delivered by the SLNs accumulates predominantly in tumor via enhanced permeability and retention effect, the enhanced passive tumor accumulation due to the loose intercellular junctions of endothelial cells lining inside blood vessels at tumor site, and the lack of lymphatic drainage. The growth of MCF-7/MDR xenografted tumor on Balb/c nude mice was inhibited to ~400 mm(3) in volume as compared with the free DOX treatment group, 1,140 mm(3), and the group treated with 1,2 distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)] solid lipid nanoparticles, 820 mm(3). Analysis of the body weight of nude mice and the histology of organs and tumor after the administration of DOX-loaded SLNs show that the SLNs have no observable side effects. These results indicate that the C-PEG-SLN is a promising platform for the delivery of therapeutic agents for MDR cancer chemotherapy.

A new approach to reduce toxicities and to improve bioavailabilities of platinum-containing anti-cancer nanodrugs.

Platinum (Pt) drugs are the most potent and commonly used anti-cancer chemotherapeutics. Nanoformulation of Pt drugs has the potential to improve the delivery to tumors and reduce toxic side effects. A major challenge for translating nanodrugs to clinical settings is their rapid clearance by the reticuloendothelial system (RES), hence increasing toxicities on off-target organs and reducing efficacy. We are reporting that an FDA approved parenteral nutrition source, Intralipid 20%, can help this problem. A dichloro (1, 2-diaminocyclohexane) platinum (II)-loaded and hyaluronic acid polymer-coated nanoparticle (DACHPt/HANP) is used in this study. A single dose of Intralipid (2 g/kg, clinical dosage) is administrated [intravenously (i. v.), clinical route] one hour before i.v. injection of DACHPt/HANP. This treatment can significantly reduce the toxicities of DACHPt/HANP in liver, spleen, and, interestingly, kidney. Intralipid can decrease Pt accumulation in the liver, spleen, and kidney by 20.4%, 42.5%, and 31.2% at 24-hr post nanodrug administration, respectively. The bioavailability of DACHPt/HANP increases by 18.7% and 9.4% during the first 5 and 24 hr, respectively.

Development of a diagnostic polymersome system for potential imaging delivery.

In order to enhance visualization of soft tissues, a dual-imaging diagnostic polymersome system featured with highly hydrated multilamellar wall structure capable of simultaneously embedding a hydrophobic near-infrared fluorophore, Cy5.5, and a paramagnetic probe, gadolinium (Gd(III)) cations was developed. The polymersomes were obtained from the self-assembly of lipid-containing copolymer, poly(acrylic acid-co-distearin acrylate), in aqueous solution. The Cy5.5 and Gd(III) species were loaded into polymersomes via hydrophobic association (loading efficiency of Cy5.5 ca 74%) and electrostatic complexation (Gd(III) 83%), respectively. The Cy5.5/Gd(III)-loaded polymersomes (CGLPs) have shown excellent payload confinement, reduced dilution effect on assembly dissociation and decreased protein/salt-induced colloidal aggregation. Owing to the highly hydrated structure of vesicular membrane, the superior contrast enhancement of CGLPs in magnetic resonance (MR) imaging was obtained as a result of prolonged rotational correlation time of Gd(III) cations and fast water exchange from Gd(III) to bulk solution. The CGLPs exhibit a 15-fold higher longitudinal relaxivity value (ca 60 mM(-1) s(-1)) than that (4 mM(-1) s(-1)) of the commercial contrast agent, Magnevist, in phosphate buffered saline. The in vivo characterization demonstrates that CGLPs exhibit a signal-to-noise ratio in T1-weighted MR image contrast similar to that of Magnevist, yet with a Gd dose 5-fold lower. An excellent contrast in NIR imaging at tumor site was attained following the intravenous injection of GGLPs into Tramp-C1 tumor-bearing mice (C57BL/6). Along with their non-toxicity at the dose used, these results demonstrate the great potential of the CGLPs as an advanced diagnostic nanodevice.

A pharmacokinetics study of radiolabeled micelles of a poly(ethylene glycol)-block-poly(caprolactone) copolymer in a colon carcinoma-bearing mouse model.

A copolymer of poly(ethylene glycol)-b-poly(caprolactone) (PEG-PCL) was modified with a benzyl moiety and labeled with I-131. A micelle system, (131)I-benzyl-micelles, formed from (131)I-benzyl-PEG-PCL and PEG-PCL-PC, was created and used for in vitro characterization and in vivo evaluation. Administration of (131)I-benzyl-micelles to a colon carcinoma-bearing mouse model gives a 4.9-fold higher tumor-to-muscle ratio at 48 h post-injection than treatment with the unimer (131)I-benzyl-PEG-PCL. Scintigraphic imaging, biodistribution results and pharmacokinetical evaluation all demonstrated that (131)I-benzyl-micelles are a plausible radioactive surrogate for PEG-PCL copolymer micelles. Modifying the amphiphilic copolymer with a benzyl moiety and labeled it with iodine-131 should make possible the real-time and noninvasive evaluation of the pharmacokinetics of copolymer micelles in vivo.

Improved photodynamic cancer treatment by folate-conjugated polymeric micelles in a KB xenografted animal model.

Photodynamic therapy (PDT) is a light-induced chemical reaction that produces localized tissue damage for the treatment of cancers and various nonmalignant conditions. In the clinic, patients treated with PDT should be kept away from direct sunlight or strong indoor lighting to avoid skin phototoxicity. In a previous study, it was demonstrated that the skin phototoxicity of meta-tetra(hydroxyphenyl)chlorin (m-THPC), a photosensitizer used in the clinic, can be significantly reduced after micellar encapsulation; however, no improvement in antitumor efficacy was observed. In this work, a folate-conjugated polymeric m-THPC delivery system is developed for improving tumor targeting of the photosensitizer, preventing photodamage to the healthy tissue, and increasing the effectiveness of the photosensitizers. The results demonstrate that folate-conjugated m-THPC-loaded micelles with particle sizes around 100 nm are taken up and accumulated by folate receptor-overexpressed KB cells in vitro and in vivo, and their PDT has no significant adverse effects on the body weight of mice. After an extended delivery time, a single dose of folate-conjugated m-THPC-loaded micelles has higher antitumor effects (tumor growth inhibition = 92%) through inhibition of cell proliferation and reduction of vessel density than free m-THPC or m-THPC-loaded micelles at an equivalent m-THPC concentration of 0.3 mg kg(-1) after irradiation. Furthermore, folate-conjugated m-THPC-loaded micelles at only 0.2 mg kg(-1) m-THPC have a similar antitumor efficacy to m-THPC or m-THPC-loaded micelles with the m-THPC concentration at 0.3 mg kg(-1) , which indicates that the folate conjugation on the micellar photosensitizer apparently reduces the requirement of m-THPC for PDT. Thus, folate-conjugated m-THPC-loaded micelles with improved selectivity via folate-folate receptor interactions have the potential to reduce, not only the skin photosensitivity, but also the drug dose requirement for clinical PDT.

Thermally induced polymeric assemblies from the PAAc-based copolymer containing both PNIPAAm and mPEG grafts in water.

Graft copolymer comprising acrylic acid (AAc) units as the backbone and poly(N-isopropylacrylamide) (PNIPAAm) and monomethoxy poly(ethylene glycol) (mPEG) as the grafts undergoes phase transition and supramolecular assembly into colloidal particles in water upon the thermally induced hydrophobic association. The structural characteristics of the polymeric assemblies made from the graft copolymer in water are strongly dependent on the copolymer concentration and the way that the copolymer solution is subjected to heating from 25 degrees C to the phase transition region (occurring in the range 30 approximately 35 degrees C). The resultant assemblies are characterized by forming hydrophobic PNIPAAm regions with the multicore architecture and intercore connections. Interesting enough, these colloidal systems obtained from the copolymer solutions at different concentrations (10.0 and 1.0 mg/mL) and heating methods (fast and slow heating) exhibit very different structural responses when subjected to further temperature increase (from 30 approximately 35 to 60 degrees C). The mutual interactions among the components (PAAc backbone and PNIPAAm and mPEG grafts) of the copolymer were shown to play a crucial role in the evolution of the ultimate assembly structure. A molecular packing model was proposed to illustrate the mechanisms of the thermally induced structural transformation processes for the amphiphilic graft copolymer in water.

Effects of SDS on the thermo- and pH-sensitive structural changes of the poly(acrylic acid)-based copolymer containing both poly(N-isopropylacrylamide) and monomethoxy poly(ethylene glycol) grafts in water.

The effects of SDS on the structural changes of the thermally induced polymeric micelles from a graft copolymer comprising poly(acrylic acid) (PAAc) as the backbone and poly(N-isopropylacrylamide) (PNIPAAm) and monomethoxy poly(ethylene glycol) (mPEG) as the grafts in aqueous solution are studied. At low temperature, SDS micelles form via the hydrophobic association of SDS molecules with the PNIPAAm grafts at a critical aggregation concentration of SDS (cac(SDS)) much lower than its critical micelle concentration. Consequently, the critical aggregation temperature of the graft copolymer is elevated. The corresponding structure of the thermally induced polymeric micelles is characterized by an abrupt reduction in the particle size and an increased tendency toward formation of the monocore structure with a more compact and hydrophobic PNIPAAm microdomain being developed. On the other hand, upon the polymeric micelle formation at high temperature, the copolymer-bound SDS micelle structure is disrupted and the dissociated SDS molecules migrate to the core-shell interface with their alkyl chains residing in the liquidlike region of the hydrophobic PNIPAAm microdomain. The correlation between the polymeric particles and copolymer-bound micelles is further substantiated by showing the change of the colloidal particle size in response to changes in cac(SDS) via adjusting the pH of the aqueous copolymer/SDS solutions.

Synthesis of pH-sensitive inulin hydrogels and characterization of their swelling properties.

In this study, pH-responsive inulin hydrogels were prepared by radical copolymerization of methacrylated inulin (MA-inulin) with acrylic acid (AAc) in aqueous solution using ammonium peroxydisulfate (APS) and N,N,N',N'-tetramethylethylenediamine (TMEDA) as an initiation system. The AAc content in hydrogels was evaluated by FTIR spectroscopy. The covalent bridging of AAc among MA moieties of MA-inulins was observed by a significant increase in the effective network density of hydrogels and further confirmed by TGA studies. While, at a low content of AAc, the hydration of hydrogels at pH 7.4 decreased owing to the increased crosslinking density, the swelling subsequently increased with further increasing AAc as a consequence of the increased ionic osmotic pressure within hydrogels. The change in swelling of hydrogels in response to pH change between 7.4 and 2.2 was therefore enlarged when the AAc content increased.

Effects of acrylic acid on preparation and swelling properties of pH-sensitive dextran hydrogels.

Dextran hydrogels were obtained by radical copolymerization of methacrylated dextran (MA-dextran) with acrylic acid (AAc) using ammonium peroxydisulfate (APS) and N,N,N',N'-tetramethylethylenediamine (TMEDA) as an initiation system in an aqueous solution. The AAc content in hydrogels was determined by FTIR. Copolymerization of MA-dextran with AAc increased the cross-linking density of hydrogels by the bridging effect of AAc and, to a certain extent, facilitated the formation of hydrogels from MA-dextran with a low degree of MA substitution (DS). For hydrogels with a low DS (5.9), the swelling at pH 7.4 initially decreased and then increased with increasing AAc. The swelling of hydrogels with high DS (11.4 and 22.4) increased gradually with AAc. This discrepancy was explained by the differences in the chemical potentials of water outside and inside of the hydrogels as a function of AAc. Further increases of AAc, however, led to a reduction in polymerization conversion and even incomplete formation of hydrogel. The reduction in polymerization yield was primarily a consequence of the pH reduction and salt formation of AAc with TMEDA.