Long-circulating zein-polysulfobetaine conjugate-based nanocarriers for enhancing the stability and pharmacokinetics of curcumin.

Though curcumin has potential treatment value for most chronic diseases, it exerts little potency in the clinic because of its low aqueous solubility, high chemical instability and poor pharmacokinetics. To enhance its potency, we developed a zein-based micelle as a nanocarrier to encapsulate curcumin. Herein, superhydrophilic zwitterionic polymers, poly(sulfobetaine methacrylate) (PSBMA), were conjugated to zein to obtain an amphiphilic zein-PSBMA conjugate. These conjugates could self-assemble into micelles composed of antifouling PSBMA shells and zein cores. The results from the cytokine secretion assay showed that the micelles induced a low level of macrophage activation. Moreover, the results from the in vivo fluorescence imaging experiment confirmed their long-circulating property, exceeding 72 h in mice. In comparison with native curcumin, micelle-encapsulated curcumin had a 230-fold increase in stability in vitro, and its half-life was 22-fold longer, according to a pharmacokinetic study on mice. Overall, this work presents a zein-PSBMA micelle with a long circulation time as a useful nanocarrier for effective curcumin delivery.

Preparation, characterization and preliminary pharmacokinetic study of pH-sensitive Hydroxyapatite/Zein nano-drug delivery system for doxorubicin hydrochloride.

OBJECTIVES: Zein nanoparticles (Zein NPs) were used as a hydroxyapatite (HA) biomineralization template to generate HA/Zein NPs. Doxorubicin hydrochloride (DOX) was loaded on HA/Zein NPs (HA/Zein-DOX NPs) to improve its pH-sensitive release, bioavailability and decrease cardiotoxicity. METHODS: HA/Zein-DOX NPs were prepared by phase separation and biomimetic mineralization method. Particle size, polydispersity index (PDI), Zeta potential, transmission electron microscope, X-ray diffraction and Fourier-transform infrared spectroscopy of HA/Zein-DOX NPs were characterized. The nanoparticles were then evaluated in vitro and in vivo. KEY FINDINGS: The small PDI and high Zeta potential demonstrated that HA/Zein-DOX NPs were a stable and homogeneous dispersed system and that HA was mineralized on Zein-DOX NPs. HA/Zein-DOX NPs showed pH-sensitive release. Compared with free DOX, HA/Zein-DOX NPs increased cellular uptake which caused 7 times higher in-vitro cytotoxicity in 4T1 cells. Pharmacokinetic experiments indicated the t1/2ß and AUC0- t of HA/Zein-DOX NPs were 2.73- and 3.12-fold higher than those of DOX solution, respectively. Tissue distribution exhibited HA/Zein-DOX NPs reduced heart toxicity with lower heart targeting efficiency (18.58%) than that of DOX solution (37.62%). CONCLUSION: In this study, HA/Zein-DOX NPs represented an antitumour drug delivery system for DOX in clinical tumour therapy with improved bioavailability and decreased cardiotoxicity.

Drug stabilization in the gastrointestinal tract and potential applications in the colonic delivery of oral zein-based formulations.

In recent years, various oral dosage forms using biomaterials have been developed to deliver drugs to the colon for therapy due to the advantages of local treatment and its ideal location for drug delivery. To achieve site-specific delivery, the complete drug should be released in the colon, while the drug must be protected or their delivery minimized in the stomach and small intestine. The use of natural or synthetic polymers has been reported for these purposes. The roles of zein in drug delivery have been identified with various types of formulations for improving bioavailability, controlled drug release and targeted delivery. Although zein has been demonstrated as a potential material for pharmaceutical applications, a review of zein in the gastrointestinal tract for stabilizing drug- and colon-specific delivery is still missing. In the present review, we aim to provide typical strategies for using zein in formulations to minimize drug release/ensure drug protection in the upper part of the gastrointestinal tract. Furthermore, effective fabrications or modifications for drug release in the colon will be highlighted. This primary resource of related methods of using zein in the gastrointestinal tract will advance technologies for using it as a natural polymer for drug delivery.

Fabrication and Characterization of Zein Composite Particles Coated by Caseinate-Pectin Electrostatic Complexes with Improved Structural Stability in Acidic Aqueous Environments.

Zein composite particles coated with caseinate-pectin electrostatic complexes (zein-caseinate-pectin particles) were fabricated using an electrostatic deposition and liquid-liquid dispersion method without heating treatment. Compared to zein particles coated only with caseinate, the acidic stability of zein-caseinate-pectin particles was greatly improved, and the particle aggregation was suppressed at pH 3-6, especially at pH values near the isoelectric point of caseinate (pH 4-5). Besides, desirable long-term storage stability and re-dispersibility were observed. Under different zein to curcumin (Cur) feeding ratios (10:1, 20:1, 30:1 and 40:1, w/w), the Cur-loaded zein-caseinate-pectin particles had a spherical shape with an average diameter ranging from 358.37 to 369.20 nm, a narrow size distribution (polydispersity index < 0.2) and a negative surface charge ranging from -18.87 to -19.53 mV. The relatively high encapsulation efficiencies of Cur (81.27% to 94.00%) and desirable re-dispersibility were also achieved. Fluorescence spectroscopy indicated that the encapsulated Cur interacted with carrier materials mainly through hydrophobic interactions. The in-vitro release profile showed a sustained release of Cur from zein-caseinate-pectin particles in acidic aqueous environment (pH 4) up to 24 h, without any burst effect. In addition, the encapsulation retained more ABTS•+ radical scavenging capacity of Cur during 4 weeks of storage. These results suggest that zein-caseinate-pectin particles may be used as a potential delivery system for lipophilic nutrients in acidic beverages.

Rapamycin loaded TPGS-Lecithins-Zein nanoparticles based on core-shell structure for oral drug administration.

Rapamycin as a novel macrolide immunosuppressive agent has been commonly used in organ transplantation owing to its stronger immunosuppressive effect, non-nephrotoxicity and lower side effect. However its drawbacks of low bioavailability and big individual difference remain to be improved in clinical application. Here rapamycin loaded TPGS-Lecithins-Zein nanoparticles (RTLZ-NPs) with core-shell structure were prepared by the phase separation method. The RTLZ-NPs were approximately 190.3 nm in size, with PDI and zeta potential about 0.256 and -19.71 mV respectively. Drug entrapment and loading achieved were about 86.64 and 25.73% respectively. Meanwhile RTLZ-NPs exhibited favorable enzymolysis resistance abilities in gastrointestinal environments and enhanced uptake in Caco-2 cells. The optimum absorption sites of rapamycin in the intestine were duodenum and jejunum as single-pass intestinal perfusion assay. Upon also considering the results of Caco-2 cell assay, it could be speculated that the transport of rapamycin in vivo involved active transport as well as P-glycoprotein (P-gp) based efflux. Finally, the relative oral bioavailability of RTLZ-NPS was 4.33 fold higher than free rapamycin in SD rat. Altogether the designed nanoparticles can be an efficient oral delivery strategy for rapamycin analogues to prevent the attacks from destructive enzymes, reduce cell efflux, increase cell uptake, and then enhance the oral bioavailability.

Metabolism, Excretion, and Tissue Distribution of Astilbin-Zein Nanoparticles in Rats.

The excretion, tissue distribution, and metabolic profile of astilbin in rat were studied by HPLC and UPLC-QTOF-MS. Astilbin underwent isomerization in the small intestine, and its four isomers were found in feces. Besides, taxifolin, the aglycone of astilbin, and its further metabolites by gut microbes through hydrogenation, dehydration, and ring-fission were found. The total feces excretion of astilbin was about 14.4% of administration. The forming of zein-caseinate nanoparticles can significantly delay and reduce the feces excretion of astilbin. Astilbin and its isomers were absorbed in their intact form. The main metabolites found in plasma and tissues were the methylated products. Astilbin was rapidly distributed in various tissues including brain and maintained relatively high concentration in heart. Compared with other tissues, significantly higher concentration and longer duration of astilbin were found in the gastrointestinal tract. Astilbin and its isomers were excreted in their intact and methylated form in urine.

Bioadhesive Food Protein Nanoparticles as Pediatric Oral Drug Delivery System.

The goal of this study was to develop bioadhesive food protein nanoparticles using zein (Z), a hydrophobic corn protein, as the core and whey protein (WP) as the shell for oral pediatric drug delivery applications. Lopinavir (LPV), an antiretroviral drug, and fenretinide, an investigational anticancer agent, were used as model drugs in the study. The particle size of ZWP nanoparticles was in the range of 200-250 nm, and the drug encapsulation efficiency was >70%. The nanoparticles showed sustained drug release in simulated gastrointestinal fluids. ZWP nanoparticles enhanced the permeability of LPV and fenretinide across Caco-2 cell monolayers. In both ex vivo and in vivo studies, ZWP nanoparticles were found to be strongly bioadhesive. ZWP nanoparticles enhanced the oral bioavailability of LPV and fenretinide by 4 and 7-fold, respectively. ZWP nanoparticles also significantly increased the half-life of both drugs. The nanoparticles did not show any immunogenicity in mice. Overall, the study demonstrates the feasibility of developing safe and effective food protein-based nanoparticles for pediatric oral drug delivery.

Novel zein-based multilayer wound dressing membranes with controlled release of gentamicin.

Recently, functional multilayer scaffolds with controlled drug release ability come into prominence for wound healing applications to mimic the layered structure of skin tissue and prevent the possible infections at the defect site. In this study, controlled antibiotic releasing zein bilayer membranes were fabricated for treatment of acute skin infections. Gentamicin loaded fibers were prepared by electrospinning on the membrane surface. Membranes were characterized with scanning electron microscope, atomic force microscopy, Fourier transform infrared spectroscopy, contact angle, mechanical analysis, swelling, degradation, and water vapor permeability studies. In vitro cytotoxicity, cell attachment, and proliferation were investigated. Cell attachment on fiber layer was observed with fluorescence imaging. Fabricated fibers showed structural similarity to the skin tissue layers with a fiber diameter range of 350-425 nm and film thickness in the range of 311-361 µm. Mechanical properties were found compatible with the skin tissue. In addition, membranes showed antimicrobial activity against Staphylococcus aureus and Escherichia coli. The sustained release was achieved with a cumulative release of 94%. Membranes did not show any cytotoxic effect. NIH/3T3 and HS2 cell lines were proliferated on each layer mimicking the multilayer skin tissue. Hence, zein-based bilayer membrane showed promising properties to be used as a potential antimicrobial wound dressing for skin tissue regeneration. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2057-2070, 2019.

The formation of zein-chitosan complex coacervated particles: Relationship to encapsulation and controlled release properties.

The complex coacervation between zein and chitosan (CS) as well as the relationship with the controlled release properties of their complex nanoparticles were studied. The factors influencing the nanoparticle formation between zein and CS, including solid to liquid ratio, zein to CS ratio and pH, were systematically investigated. The isothermal titration calorimetry (ITC) showed that zein-CS interaction was spontaneous exothermic process. The pH the higher was, the stronger the interaction between zein and CS. The mean particle sizes of ZCNPs were increased by enhanced turbidity between zein and CS (from 90.89 nm to 1368.77 nm). The morphology study showed that spherical particles and coacervate were obtained with the increased interaction between zein and CS. The release profiles of curcumin in vitro indicated that slight burst effect followed by slow release was observed after interacting CS. The ZCNPs at pH 4.0 exhibited smaller particle size (162.07 nm), more stable ζ-potential (49.7 mV), higher encapsulation efficiency (94.67%) and slower release rate. In conclusion, the stronger the interaction was, the lower the curcumin released from the nanoparticles in vitro, and the ZCNPs at pH 4.0 had better potential in oral delivery application.

Zein Nanoparticles Uptake by Hydroponically Grown Soybean Plants.

In the interest of developing and characterizing a polymeric nanoparticle pesticide delivery vehicle to soybeans, zein nanoparticle (ZNP) uptake by the roots and biodistribution to the leaves of soybean plants was measured. Zein was tagged with fluorescein isothiocyanate (FITC) and made into nanoparticles (135 ± 3 nm diameter. 0.202 ± 0.034 PDI and 81 ± 4 mV zeta-potential at pH 6) using an emulsion-diffusion method. After 10 days of hydroponic exposure, association between particles and roots of plants was found to vary based on bulk nanoparticle concentration. While 0.37 mg NP/mg dry weight were detected in roots immersed in 0.88 mg NP/mL nanoparticle suspension, 0.58 mg NP/mg dry weight associated with roots immersed in a high dose nanoparticle suspension of 1.75 mg NP/mL at 10 days. Nanoparticle root uptake followed second order kinetics. A small amount of increased fluorescence was detected in the hydroponically exposed plant's leaves, suggesting that either small amounts of particles or other fluorescent contaminants of zein were up taken by the roots and biodistributed within the plant. To the authors' knowledge, this is the first study in which the uptake and time-dependent association between polymeric nanoparticles and soybeans are quantified.

Green self-assembly of zein-conjugated ZnO/Cd(OH)Cl hierarchical nanocomposites with high cytotoxicity and immune organs targeting.

Inorganic nanomedicines in the fight against cancer have progressed rapidly during recent years, with the synergistic advantages of multifunctional nanosystems compared to single component. Herein, a drug-combination opinion was introduced into "nanomedicine" based on the understanding of Trojan horse-anti-tumor mechanism of inorganic nano-medicines. Moreover, we reported the green and facile synthesis route of mono-dispersed and rod-like zein-conjugated ZnO/Cd(OH)Cl hierarchical nanocomposites. We found that the nanocomposites exhibited high-efficiency killing ability to tumor cells through lipid peroxidation mediated-membrane disintegration route. The safety studies in BALB/c mice didn't detect injection anaphylaxis, hemolysis and cytotoxicity. More interestingly, the nano-composites could specially accumulate in liver and kidney, which will be helpful for targeting cure to these regional cancers.

Preparation, characterization and application of a novel biodegradable macromolecule: carboxymethyl zein.

Zein, a naturally biocompatible and biodegradable macromolecule, is widely used as plastic film material; however, the poor water solubility limits its other applications. In this study, we aimed to obtain carboxymethyl zein (CM-zein) by modifying it with sodium monochloroacetate in weakly basic environment. CM-zein showed a new FTIR peak of C-O-C bond at 1080 cm(-1), with a new signal region appearing at 4.0-4.05 ppm that assigned to the protons of the CH2 group from a carboxymethyl on (1)H NMR and a Tg of 168.0 °C by thermal analysis. Compared with the -12.3 mV of zeta potential of unmodified zein, CM-zein increased it significantly to -23.9 mV as a consequence of carboxymethylation. 5-Fluorouracil (5-FU), a model drug used in CM-zein-based tablet, was rarely detected in 0.1 mol/L HCl (pH 1.0) but it was released massively and quickly in phosphates buffer (pH 6.8) in vitro assays. The unmodified zein-based tablet illustrated much lower release level in these two fluids. Furthermore, the pharmacokinetic study of rats showed that CM-zein released 5-FU in intestine but not in stomach after dissolving. These findings indicated that CM-zein has the potential to be used for enteric preparation as a novel pH-selective biomaterial.

Preparation and in vitro release of zein microparticles loaded with prednisolone for oral delivery.

Zein has been proposed as a polymer for targeted-drug delivery via the oral route. Zein microparticles were loaded with prednisolone and evaluated as an oral delivery system. Microparticles were formulated using phase separation. Starting quantities of zein and prednisolone, along with the agitation method and temperature were found to significantly impact drug loading and loading efficiency. Vortex mixing produced the highest drug loading and loading efficiency. Drug release was measured in simulated conditions of the stomach and small intestine using the microparticles made with the method that best improved drug loading. In simulated stomach and small intestine conditions, prednisolone release reached almost 70% over 3 and 4 h, respectively. While a clinically relevant dose may be delivered using c. 100 mg of zein microparticles, prednisolone release from the microparticles indicates that they may not be suited as a controlled- or targeted-delivery system.

The biodegradation of zein in vitro and in vivo and its application in implants.

A unique polymer-based sustained-release implant drug delivery system was prepared by using biocompatible and biodegradable Zein as the skeleton material. After preparing Zein colloids, the Zein-loaded implant rods were formulated by injection molding followed by evaporating the solvent, and being coated with poly(lactic-co-glycolic) acid (PLGA) solution. Drug release kinetics was examined by using Fluorouracil (5-FU) as model drug. Nearly zero-order release was achieved for the model drugs for a period of 0-25 days when the implants were incubated in distilled water at 37 °C. And then the degradation kinetics of the rods in vivo and in vitro were evaluated, which indicated that Zein could be absorbed by body and has good degradation property. The effects of different ratios of Zein/5-FU and the rods' diameter on drug release were studied, respectively. The plasma concentration of 5-FU in the implants were determined by HPLC after implanting a single dose of the implants in rats. All data were subsequently processed by using the computer program 3P97, and the values were showed as follows: the area under the plasma concentration-time curve (AUC) value was 321.88 (µg/ml) × day, and the mean residence time (MRT) value was 23.05 days. The sustained-release implants of Zein/5-FU were successfully formulated. The uniqueness of the article is that Zein has been used as a skeleton material in implant delivery system for the first time and zero-order release kinetics has been obtained successfully.

In vitro study of the release properties of soy-zein protein microspheres with a dynamic artificial digestive system.

The purpose of this work was to study the performance of microspheres of soy protein isolate (SPI), zein, or SPI-zein complex as vehicles of nutraceutical delivery under fasting and prandial conditions in an artificial digestive system (TIM-1). Riboflavin availability for absorption from the small intestine compartments reached 90% of the total load within 4 h, most of it (65-80%) turning up in the jejunum dialysis fluid, suggesting that this segment is the main site of absorption, regardless of the nature of the microspheres. However, the riboflavin concentrations and the availability for absorption profiles depended on microsphere formulation. Release from pure SPI and zein microspheres in the stomach compartment occurred within 15 min. The availability for absorption from both the jejunum and ileum compartment followed first-order kinetics, indicating that the limiting step in nutrient uptake with these two formulations is absorption by passive diffusion. SPI-zein complex microspheres provided sustained release of riboflavin over 4 h and a near-zero-order nutrient availability for absorption profile in both fasting and prandial states. Suspending SPI-zein complex microspheres in yogurt significantly delayed nutrient release, which would increase the likelihood of gastric-sensitive nutrients passing intact into the intestine for absorption. SPI-zein complex microspheres thus show potential for use as nutraceutical delivery vehicles in the creation of novel functional foods.

Diffusional properties of zein membranes and matrices.

INTRODUCTION: Zein is a hydrophobic corn protein, rich in leucine, proline, and alanine, that has been investigated as an excipient in pharmaceutical formulations, maybe used as a biodegradable/biocompatible material for controlled release formulations. Zein's swelling behaviors under different conditions (e.g., pH, ionic strength, and permeant's charge) were investigated in a previous study and it showed that swelling indeed influenced zein's permeation. METHODS: The diffusional behavior of model drugs through or from zein systems was investigated. Diffusional parameters such as effective diffusion coefficients, porosities, and tortuosities were calculated from release and membrane diffusion profiles for zein matrices and membranes. In addition, an alternative method of calculating porosity and tortuosity was proposed. RESULTS: The diffusional properties of zein systems appear to be primarily through aqueous channels that form during hydration and swelling in aqueous media. Permeation and release results show that the amount of diffused or released drug depends on permeant solubility and matrix/membrane permeability parameters (i.e., porosity and tortuosity). DISCUSSION: Calculated diffusional parameters for zein matrices and membranes support the aqueous channel model. CONCLUSIONS: Zein membranes and matrices hydrate and swell to form aqueous channels that are the dominant diffusional pathways.

Zein microspheres as drug/antigen carriers: a study of their degradation and erosion, in the presence and absence of enzymes.

In the laboratory, zein microspheres are being investigated as drug/vaccine delivery systems. Preliminary experiments revealed that the release of an entrapped solute (ovalbumin, a model antigen) was limited when particles were incubated in phosphate buffered saline over a number of days. To understand the slow and limited release of the guest molecule and predict microsphere fate in vivo, the degradation of zein microspheres in different media, in the presence and in the absence of enzymes, was investigated in vitro. Zein microspheres were incubated in five different media: chloride Buffer (pH 2), Acetate Buffer (pH 5), Phosphate Buffered Saline (pH 7.4), gastric simulated fluid and gastro-intestinal simulated fluid for 1 week. Changes in suspension turbidity and pH, microsphere morphology and zein composition in the release medium was followed with time. The results showed that zein microspheres were extremely resistant to degradation in the absence of enzymes (which explains the slow release of entrapped solute), but were degraded by pepsin and pancreatin enzymes in simulated gastric and intestinal fluids, respectively (which indicates that release is likely to be much faster following oral microsphere administration). However, when administered via routes where enzymes are not present, e.g. intra-muscular, release is likely to be slow.

Renal chemoembolization with mitomycin c/Ethibloc: pharmacokinetics and efficacy in an animal model.

BACKGROUND AND PURPOSE: Arterial embolization can be an alternative treatment for kidney malignancy. We investigated the efficacy of renal embolization with a combination of an occlusive agent (Ethibloc) and the cytotoxic substance mitomycin C (MMC) in an animal model. MATERIALS AND METHODS: In 32 rats with implanted Yoshida sarcoma, nephrectomy was carried out 15, 30, 60, or 90 minutes after chemoembolization (1 mg v 2 mg of MMC/mL of Ethibloc) or chemoperfusion (1 mg of MMC/mL of NaCl) of the tumor-bearing kidney. The MMC tissue concentration was measured in the kidney specimens. Six dogs also underwent chemoembolization or chemoperfusion with monitoring of MMC serum concentration at the same intervals. We compared the survival time of rats with Yoshida sarcoma after chemoembolization (N = 15), chemoperfusion (N = 18), embolization (N = 18), nephrectomy (N = 21), and no treatment (N = 25). RESULTS: The MMC tissue concentration in the rat model was much higher after chemoembolization than after chemoperfusion for at least 1.5 hours. The MMC serum concentration in the dogs showed a high initial peak (0.6 mg/L) after chemoperfusion, then dropped quickly to the same level seen 30 minutes after chemoembolization with 1 mg of MMC/mL of Ethibloc (0.15 mg/L). The MMC serum concentration following chemoembolization with 2 mg of MMC/mL of Ethibloc stayed higher (0.3-0.25 mg/L) for 60 minutes. The survival rates after nephrectomy were equal to those after chemoembolization (80% survival after 30 days), with poorer survival being seen after embolization (75%) and chemoperfusion (70%). In the control group, all rats were dead at the 27th day. CONCLUSION: Chemoembolization produces persistently high tissue concentrations of MMC and avoids toxic peak serum levels. It improves the efficacy of organ ablative vasoocclusion in renal malignancies.