Drug Loading Ratio Research Articles

Abstract 2640: RN927C, a potent site-specific Trop-2 antibody-drug-conjugate (ADC) for treatment of solid tumors

Abstract Human trophoblast cell surface antigen-2 (Trop-2), also known as TACSTD2, EGP-1, GA733-1 and MS1, is expressed on a variety of human carcinomas and its expression is often associated with poor prognosis of the diseases. Trop-2 is frequently detected in many tumor types at high levels, however, it is also present on the epithelium of a number of normal tissues. A comprehensively designed Trop-2-targeting ADC, balancing both efficacy and toxicity, is necessary to achieve clinical utility. We developed a site-specific cleavable Trop-2-ADC (RN927C) using a novel transglutaminase-mediated enzymatic conjugation method and a proprietary MTI (microtubule inhibitor) linker-payload. Our site-specific conjugation technology enables a precise drug-loading ratio of two and thus a better control of desired potency. Robust in vitro cytotoxicity of RN927C was observed selectively on multiple Trop-2 expressing tumor cell lines, with IC50 generally in the sub-nM range. Upon binding to surface Trop-2, RN927C internalized quickly and trafficked to the lysosomal compartment, as visualized by the co-localization of RN927C with lysosomal marker LAMP-2. As expected for a MTI-containing ADC, RN927C readily induced mitotic arrest of treated cells in vitro and in vivo, followed by subsequent cell death. The in vivo efficacy of RN927C was tested in multiple tumor models including pancreatic, NSCLC, and ovarian cell line and patient-derived xenograft models. Single dose administration of RN927C at 1.5 mg/kg was generally sufficient to induce sustained regression of Trop-2 expressing tumors and showed superior efficacy over standard treatment with paclitaxol or Gemcitabine. Furthermore, addition of RN927C to Gemcitiabine greatly enhanced its in vivo efficacy. RN927C was well-tolerated in non-human primates upon repeat dosing at 6mg/kg q2w, with non-severe toxicity observed primarily in skin and oral mucosa, consistent with Trop-2 expression in these epithelial tissues. Importantly, only minimal off-target hematological toxicity was observed in monkeys. Based on the combined efficacy and safety results, RN927C is expected to have a favorable therapeutic index and clinical development is currently underway. Citation Format: Shu-Hui Liu, Pavel Strop, Thomas-Toan Tran, Magdalena Dorywalska, Katherine Delaria, Wei-Hsien Ho, Russell Dushin, Jaume Pons, Arvind Rajpal, Dave Shelton. RN927C, a potent site-specific Trop-2 antibody-drug-conjugate (ADC) for treatment of solid tumors. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2640. doi:10.1158/1538-7445.AM2014-2640

The C(RgdyK)-conjugated Fe3O4 nanoparticles with high drug load for dual-targeting integrin alpha(v)beta3-expressing cancer cells.

A novel drug delivery system c(RGDyK)-modified Fe3O4 nanoparticles with high DOX load (R-DMP), which combines magnetic targeting, integrin alpha(v)beta3 targeting and high drug loading properties, was developed by chemical coupling both doxorubicin and peptide c(RGDyK) on the synthetic dual function magnetic nanoparticles (DMP) using a multi-hand cross-linker poly-L-glutamic acid. R-DMP has high drug loading ratio and trapping efficiency for magnetic targeting, and the drug loading ratio can be controlled by adjusting the reactant ratio. Moreover, R-DMP presents narrow size distribution and is sensitive to pH for drug releasing. Compare with those of doxorubicin coupled DMP without peptide c(RGDyK) modification, D-DMP shows enhanced uptake by integrin alpha(v)beta3 targeting expressing tumor cells and displays stronger cancer cell cytotoxicity. This investigate provides a new approach for the dual-targeted delivery of therapeutic agents to tumors with controlled low carrier toxicity and high efficiency.

Preparation and in vitro/in vivo characterization of enteric-coated nanoparticles loaded with the antihypertensive peptide VLPVPR

Our previous study revealed that the peptide Val-Leu-Pro-Val-Pro-Arg (VLPVPR), which was prepared using deoxyribonucleic acid recombinant technology, effectively decreased the blood pressure of spontaneous hypertensive rats; however, the effect only lasts 6 hours, likely due to its low absorption in the gastrointestinal tract. To overcome this problem, the purpose of this study was to characterize (methoxy-polyethylene glycol)-b-poly(D,L-lactide-co-glycolide)-b-poly(L-lysine) nanoparticles as in vitro and in vivo carriers for the effective delivery of VLPVPR. In our study, the VLPVPR nanoparticles were prepared using a double emulsion method, coated with Eudragit S100, and freeze-dried to produce enteric-coated nanoparticles. The optimized parameters from the double emulsion method was obtained from orthogonal experiments, including drug loading (DL) and encapsulated ratio (ER) at 6.12% and 86.94%, respectively, and the average particle size was below 100 nm. The release experiment demonstrated that the nanoparticles were sensitive to pH: almost completely released at pH 7.4 after 8 hours, but demonstrated much less release at pH 4.5 or pH 1.0 in the same amount of time. Therefore, the nanoparticles are suitable for enteric release. In vivo compared with the untreated group, the medium and high doses of orally administered VLPVPR nanoparticles reduced blood pressure for more than 30 hours, demonstrating that these nanoparticles have long-lasting and significant antihypertensive effects in spontaneously hypertensive rats.

Magnetic Core–Shell Nanocapsules with Dual‐Targeting Capabilities and Co‐Delivery of Multiple Drugs to Treat Brain Gliomas

Lactoferrin (Lf)-tethered magnetic double emulsion nanocapsules (Lf-MDCs) are assembled from polyvinyl alcohol (PVA), polyacrylic acid (PAA), and iron oxide (IO) nanoparticles. The core-shell nanostructure of the Lf-MDCs (particle diameters from 100 to 150 nm) can simultaneously accommodate a hydrophilic drug, doxorubicin (Dox), and a hydrophobic drug, curcumin (Cur), in the core and shell, respectively, of the nanocapsules for an efficient drug delivery system. The release patterns of the two drugs can be regulated by manipulating the surface charges and drug-loading ratios, providing the capability for a stepwise adjuvant release to treat cancer cells. The results demonstrate that the dual (Dox+Cur)-drug-loaded nanocapsule can be effectively delivered into RG2 glioma cells to enhance the cytotoxicity against the cells through a synergistic effect. The combined targeting, i.e., magnetic guidance and incorporation of Lf ligands, of these Lf-MDCs results in significantly elevated cellular uptake in the RG2 cells that overexpress the Lf receptor. Interestingly, an intravenous injection of the co-delivered chemotherapeutics follows by magnetic targeting in brain tumor-bearing mice not only achieve high accumulation at the targeted site but also more efficiently suppress cancer growth in vivo than does the delivery of either drug alone.

<i>Antheraea pernyi</i> Silk Fibroin Nanoparticles for Drug Delivery

Silk nanoparticles were easily obtained from regenerated Antheraea Pernyi Silk Fibroin (ASF). The morphology and average size of the silk particles was sensitive to pH value of fibroin solution. The diameter of nanoparticles prepared was in the range of 30 nm to 1000 nm with a narrow size distribution. On this process, the molecular conformation of regenerated ASF changed from α-helix to β-sheet structure. The shape of prepared nanoparticles were regular spherical structure when the pH value was about 4.3 (pI) in ASF solution. Doxorubicin hydrochloride (DOX) was loaded in the ASF particles as drug release model and the drug-loading ratio was 3.4 %. The release rate of DOX from ASF nanoparticles was pH sensitive. After 23 days release, there was still 84% DOX in the ASF nanoparticles. The result suggested that the ASF nanoparticles might be suitable microcarriers for drug delivery.

FABRICATION AND IN VITRO EVALUATION OF FOLATE-MODIFIED IRON FERRITE NANOPARTICLES WITH HIGH DOXORUBICIN LOADING FOR RECEPTORS-MAGNETIC-GUIDED DRUG DELIVERY

Folate-modified iron ferrite nanoparticles with high doxorubicin loading (FDMP) were developed for dual targeting of tumor cells. Large quantities of doxorubicin and folate ligand were chemically coupled to the synthesized dual-functional magnetic nanoparticles by using the multihand cross-linker poly-L-glutamic acid. FDMP exhibits high drug loading ability, narrow size distribution and pH sensitivity to drug release. The drug loading ratio and the magnetic response can be adjusted by controlling the reactant ratio. FDMP possesses high magnetic-guided ability and exhibits enhanced uptake by folate receptors expressing tumor cells and increased cancer cell cytotoxicity.

Functional materials from the covalent modification of reduced graphene oxide and β-cyclodextrin as a drug delivery carrier

We report a drug delivery system based on the covalently reduced graphene oxide (rGO) with p-aminobenzoic acid (rGO-C6H4-COOH) for the loading and targeted delivery of the anticancer drug, doxorubicin (DOX). The colloidal solution of rGO-C6H4-COOH conjugated by polyethyleneimine (PEI) and Biotin was prepared. This endows the colloidal solution of rGO-C6H4-CO-NH-PEI-NH-CO-Biotin, which presents excellent water-solubility and targeting as a drug delivery system. β-Cyclodextrin (β-CD) molecules, which are host molecules for accommodating guest molecules, such as water insoluble anticancer drugs, were introduced to reduce the cytotoxicity of the drug delivery system and to improve the biocompatibility. The drug delivery of rGO-C6H4-CO-NH-PEI-NH-CO-CD-Biotin has a ∼24.64% drug (DOX) loading ratio. The drug release behavior was pH dependent at higher DOX concentrations, but salt dependent at lower DOX concentrations, which could be exploited for controlled drug release in cancer cells. The DOX loaded on rGO-C6H4-CO-NH-PEI-NH-CO-CD-Biotin could effectively induce HepG2 cancer cell apoptosis. This can be explained by the conjugation of DOX and rGO-C6H4-CO-NH-PEI-NH-CO-CD-Biotin being able to arrest the cancer cells in the G2 phase, which is the most sensitive to the anticancer drug.

Synthesis of pH-responsive mesoporous silica nanotubes for controlled release

A novel mesoporous silica tubes (MMT) which possessed pH-sensitive controlled release ability had been fabricated and synthesized by using carbon nanotubes (CNTs) as template. The sample replicated the morphologies of the CNTs successfully. The Brunauer–Emmett–Teller surface area of the materials can reach 1,017 m2 g−1 with the pore size of 3.8 nm. As a model drug, metformin HCl was applied to study the drug loading and control release ability of the materials. MMT possesses higher drug loading ratio (36 %) than that of MCM-41 (27.5 %). The release kinetics were studied in simulated gastric fluid (pH = 1.2) and in simulated proximal intestine fluid (pH = 7. 4), respectively. The result shows that the delivery systems exhibit well pH-sensitive control release ability and the as-synthesized materials have potential application in biomedical field.

Characterisation and drug release performance of biodegradable chitosan–graphene oxide nanocomposites

Biodegradable chitosan–graphene oxide (GO) nanocomposites possess improved mechanical properties and drug delivery performance over chitosan and could prove to be a viable, controlled and pH-sensitive transdermal drug delivery system. Chitosan nanocomposites containing varying GO contents and drug loading ratios were investigated. The nanocomposite with 2wt % GO provided the optimal combination of mechanical properties and drug-loading capacity. It offered a faster and a more substantial release of drug than chitosan as well as a slower biodegradation rate, owing to the abundant oxygenated functional groups, hydrophilicity and large specific surface area of GO sheets. The drug delivery profiles of the nanocomposite were dependent on the drug loading ratio, with 0.84:1 being the best ratio of drug to GO for a quick and high release of the loaded drug. The nanocomposite also demonstrated pH sensitivity of drug release, releasing 48% less drug in an acidic condition than in a neutral environment.

Study on preparation process of artesunate polylactic acid microspheres

This study aims to investigate the preparation process and in vitro release behavior of artesunate polylactic acid microspheres, in order to prepare an artesunate polylactic acid (PLA) administration method suitable for hepatic arterial embolization. With PLA as the material and polyvinyl alcohol (PVA) as the emulsifier, O/W emulsion/solvent evaporation method was adopted to prepare artesunate polylactic acid microspheres, and optimize the preparation process. With drug loading capacity, encapsulation efficiency and particle size as indexes, a single factor analysis was made on PLA concentration, PVA concentration, drug loading ratio and stirring velocity. Through an orthogonal experiment, the optimal processing conditions were determined as follows: PLA concentration was 9. 0% , PVA concentration was 0. 9% , drug loading ratio was 1:2 and stirring velocity was 1 000 r x min(-1). According to the verification of the optimal process, microsphere size, drug loading and entrapment rate of artesunate polylactic acid microspheres were (101.7 +/- 0.37) microm, (30.8 +/- 0.84)%, (53.6 +/- 0.62)%, respectively. The results showed that the optimal process was so reasonable and stable that it could lay foundation for further studies.

Preparation and characterisation of andrographolide niosomes and its anti-hepatocellular carcinoma activity

Objective: In this study, a novel andrographolide (AG) preparation formulation, niosomes, was prepared to improve the bioavailability and tissue distribution of AG.Methods: The niosomal formulation of AG was prepared by film hydration/sonication method and tissue distribution was measured by liquid chromatography-mass spectrometry (LC-MS) method in mice, and anti-hepatocellular carcinoma (anti-HCC) activity was examined by MTT method in HepG2.Results: Entrapment efficiency, drug-loading ratio and average particle size of AG niosomes were 72.36%, 5.90% and 206 nm, respectively. The tissue distribution in mice demonstrated that the AG niosomes were absorbed in liver much more than the free AG. Furthermore, the anti-HCC activity in HepG2 cells showed that there was no significant difference between free AG and AG niosomes.Conclusion: The present results suggest that AG niosomes may have a significant potential of liver targeting, which is valuable in chemotherapy of HCC.

Increased In Situ Intestinal Absorption of Phytoestrogenic Diarylheptanoids from Curcuma comosa in Nanoemulsions

Curcuma comosa has long been used as a gynecological medicine. Several diarylheptanoids have been purified from this plant, and their pharmacological effects were proven. However, there is no information about the absorption of C. comosa components to support the formulation usage. In the present study, C. comosa hexane extract and the mixture of its two major compounds, (4E,6E)-1,7-diphenylhepta-4,6-dien-3-ol (DA1) and (6E)-1,7-diphenylhept-6-en-3-ol (DA2), were formulated into nanoemulsions. The physical properties of the nanoemulsions and the in situ intestinal absorptions of DA1 and DA2 were evaluated. The results demonstrated the mean particle sizes at 0.207 ± 0.001 and 0.408 ± 0.014 μm, and the zeta potential at -14.57 ± 0.85 and -10.47 ± 0.32 mV for C. comosa nanoemulsion (C.c-Nano) and mixture of diarlylheptanoid nanoemulsions (DA-Nano), respectively. The entrapments of DA1 and DA2 were 76.61% and 75.41%, and 71.91% and 71.63% for C.c-Nano and DA-Nano, respectively. The drug loading ratios of DA1 and DA2 were 351.47 and 614.53 μg/mg, and 59.48 and 126.72 μg/mg for C.c-Nano and DA-Nano. The intestinal absorption rates of DA1 and DA2 were 0.329 ± 0.015 and 0.519 ± 0.026 μg/min/cm2 in C.c-Nano, and 0.380 ± 0.006 and 0.428 ± 0.036 μg/min/cm2 in DA-Nano, which were five to ten times faster than those in oil. In conclusion, the formulation in nanoemulsion forms obviously increased the intestinal absorption rate of diarylheptanoids.

Smart pH-Sensitive and Temporal-Controlled Polymeric Micelles for Effective Combination Therapy of Doxorubicin and Disulfiram

The combination of a chemotherapeutic drug with a multidrug resistance (MDR) modulator has emerged as a promising strategy for treating MDR cancer. To ensure two drugs could be simultaneously delivered to tumor region at the optimum ratio, and the MDR modulator could be released earlier and faster than the chemotherapeutic drug to inactivate P-glycoprotein (P-gp) and subsequently inhibit the pumping out of the chemotherapeutic drug, a smart pH-sensitive polymeric micelles system with high drug loading and precise drug ratio was designed and prepared by conjugating doxorubicin (DOX) to poly(styrene-co-maleic anhydride) (SMA) derivative with adipic dihydrazide (ADH) through a acid-cleavable hydrazone bond, and then encapsulating disulfiram (DSF), a P-gp inhibitor as well as an apoptosis inducer, into the micelles formed by the self-assembly of SMA-ADH-DOX (SAD) conjugate. The pH-sensitive polymeric micelles system enabled a temporal release of two drugs: encapsulated DSF was released fast to inhibit the activity of P-gp and restore cell apoptotic signaling pathways, while conjugated DOX was released in a sustained and pH-dependent manner and highly accumulated in drug resistant cells to exert therapeutic effect, due to the inactivation of P-gp by DSF. The smart co-delivery system was very effective in enhancing the cytotoxicity by increasing the intracellular accumulation of DOX and promoting the apoptotic response, and showed the most effective inhibitory effect on the growth of drug-resistant breast cancer xenografts as compared to other combinations of both drugs. In a word, this smart co-delivery system has significant promise for the clinical therapy of MDR cancer.

Preparation and Evaluation of Chitosin-Coated Alginate/Gelatin Microspheres for Sustained-Release Drug Delivery System In Vitro

The purpose of the study was to prepare and evaluation chitosin-coated alginate/gelatin microspheres for sustained-release drug delivery system in vitro. The microspheres were prepared with an emulsification technique, characterized by scanning electron microscopy (SEM), Fourier transform infrared spectrophotometry (FT-IR), differential scanning calorimetry (DSC). The average particle size of the chitosan-coated alginate/gelatin microspheres was uniform. The results of FT-IR and DSC showed that the microspheres were formed by intermolecular cross-linkages between chitosan and gelatin. The results also implied that the microsphere were a practicable dosage form to increase drug loading ratio for the poorly water-soluble drugs by encapsulated with chitosan. In vitro release of the microsphere indicated that it had a satisfactory sustained-release behavior for the sustained-release drug delivery system.

Blends of cross-linked high amylose starch/pectin loaded with diclofenac

Polymers blends represent an important approach to obtain materials with modulated properties to reach different and desired properties in designing drug delivery systems in order to fulfill therapeutic needs. The aim of this work was to evaluate the influence of drug loading and polymer ratio on the physicochemical properties of microparticles of cross-linked high amylose starch–pectin blends loaded with diclofenac for further application in controlled drug delivery systems. Thermal analysis and X-ray diffractograms evidenced the occurrence of drug–polymer interactions and the former pointed also to an increase in thermal stability due to drug loading. The rheological properties demonstrated that drug loading resulted in formation of weaker gels while the increase of pectin ratio contributes to origin stronger structures.

Parametric simulation of drug release from hydrogel-based matrices

In this work a model recently proposed to describe the drug release from hydrogel-based matrices was applied to describe the fractional drug release from matrices based on hydroxypropylmethylcellulose (HPMC) and diclofenac. The model, firstly proposed to describe the behaviour of systems based on HPMC and theophylline and a single set of preparation variables, is based on mass balances and transport phenomena evaluation and it was solved by an FEM-based numerical code. The experimental data on the HPMC-diclofenac matrices, taken from literature, have been obtained by varying the drug loading ratio, the compression force, the powder size of both the drug and the polymer. A good agreement between experimental data and model predictions, as calculated in the present work, was obtained without the use of any adjustable parameters. The predictive nature of the model has been confirmed, even changing the drug molecule and other preparative parameters.

Preparation and characterization of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHX) based nanoparticles for targeted cancer therapy

Targeted drug delivery systems are one of the most promising alternatives for the cancer therapy. Rapid developments on nanomedicine facilitated the creation of novel nanotherapeutics by using different nanomaterials. Especially polymer based nanoparticles are convenient for this purpose. In this study; a natural polymer (poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), PHBHHX) was used as a base matrix for the production of a novel nanotherapeutic including antineoplastic agent, Etoposide and attached folic acid as a ligand on the nanoparticles. Modified solvent evaporation technique was used for the production of PHBHHX nanoparticles and the average size of the obtained PHBHHX nanoparticles were observed in the range of 180 nm and 1.5 μm by the change in experimental conditions (i.e., homogenization rate, surfactant concentration and polymer/solvent ratio). By the increase in homogenization rate and surfactant concentration, size of the nanoparticles was decreased, while the size was increased by the increase in polymer/solvent ratio. Drug loading ratio was also found to be highly affected by polymer/drug ratio. Surface charge of the prepared nanoparticles was also investigated by zeta potential measurements. In the cytotoxicity tests; Etoposide loaded and folic acid attached PHBHHX nanoparticles were observed as more effective on HeLa cells than Etoposide loaded PHBHHX nanoparticles without attached folic acid. The cytotoxicity of folic acid conjugated PHBHHX nanoparticles to cancer cells was found to be much higher than that of normal fibroblast cells, demonstrating that the folate conjugated nanoparticles has the ability to selectively target to cancer cells. In addition, apoptotic/necrotic activities were evaluated for all formulations of the PHBHHX nanoparticles and parallel results with cytotoxicity tests were obtained. These studies demonstrate that the folic acid attached and Etoposide loaded PHBHHX nanoparticles seem as promising for the targeted cancer therapy.

A novel triple-responsive poly(3-acrylamidephenylboronic acid-co-2-(dimethylamino) ethyl methacrylate)/(β-cyclodextrin-epichlorohydrin)hydrogels: Synthesis and controlled drug delivery

In this work, a novel triple-responsive poly(3-acrylamidephenylboronic acid-co-(2-dimethylamino) ethyl methacrylate)/(β-cyclodextrin-epichlorohydrin) (P(AAPBA-co-DMAEMA)/(β-CD-EPI)) semi-interpenetrating (semi-IPN) hydrogel was prepared. The structures of the resultant hydrogels were studied by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The results from swelling studies reveal that the equilibrium swelling ratios (ESRs) of P(AAPBA-co-DMAEMA)/(β-CD-EPI) semi-IPN hydrogels are significantly affected by pH, temperature, ionic strength and glucose concentration of the swelling media. Release studies that used aminophylline and ibuprofen as hydrophilic and hydrophobic model drug, respectively, show that the drug loading ratio of hydrophobic drugs is apparently higher than that of hydrophilic drugs. It is also depicted that the release behaviors of model drug from the P(AAPBA-co-DMAEMA)/(β-CD-EPI) semi-IPN hydrogels depend on pH, glucose concentration and solvent type of release medium.

Control generating of bacterial magnetic nanoparticle–doxorubicin conjugates bypoly-L-glutamic acid surface modification

By using poly-L-glutamic acid (PLGA) to modify the membrane surface of bacterialmagnetic nanoparticles (BMPs), (BMP)–doxorubicin conjugates (DBMP-P) could becontrol generated. The doxorubicin loading ratio could be raised up to 81.7% (w/w) in comparison with that of dual functional linkers. DBMP-P was characterized bytransmission electron micrographs, attenuated total reflection infrared spectroscopy,magnetic properties, and dynamic light scattering. It is found that increase of thedoxorubicin/PLGA modified BMP (PBMP) ratio leads to an increase of the drug loading ratio and a decreaseof saturation magnetization. Besides, DBMP-P is sensitive to pH to facilitate drug release,shows enhancement of uptake by cancer cells, and is strongly cytotoxic to HePG2 andMCF-7 cells.

Development of efficient acid cleavable multifunctional prodrugs derived from dendritic polyglycerol with a poly(ethylene glycol) shell

In an attempt to explore the potential of dendritic systems for the development of effective anticancer drug delivery systems, we explored a simple modular approach of preparing polyglycerol doxorubicin prodrugs, with flexibility for drug loading using an acid-sensitive hydrazone linker and further post-modification with poly(ethylene glycol) shell. The resulting drug polymer conjugates showed optimal properties for in vitro and in vivo applications because of their high water solubility, an appropriate size for passive tumor targeting, a high stability at physiological conditions, pronounced acid-sensitive properties, cellular internalization, and a favorable toxicity profile. Doxorubicin polyglycerol conjugates with a high drug loading ratio showed clearly improved antitumor efficacy over doxorubicin in an ovarian xenograft tumor model (A2780) inducing transient complete remissions thus demonstrating the potential of developing efficient multifunctional dendritic drug delivery using our modular approach.