An in vitro release study of 5-fluoro-uracil (5-FU) from swellable poly-(2-hydroxyethyl methacrylate) (PHEMA) nanoparticles

pHEMA: An Overview for Biomedical Applications

Poly(2-hydroxyethyl methacrylate) (pHEMA) as a biomaterial with excellent biocompatibility and cytocompatibility elicits a minimal immunological response from host tissue making it desirable for different biomedical applications. This article seeks to provide an in-depth overview of the properties and biomedical applications of pHEMA for bone tissue regeneration, wound healing, cancer therapy (stimuli and non-stimuli responsive systems), and ophthalmic applications (contact lenses and ocular drug delivery). As this polymer has been widely applied in ophthalmic applications, a specific consideration has been devoted to this field. Pure pHEMA does not possess antimicrobial properties and the site where the biomedical device is employed may be susceptible to microbial infections. Therefore, antimicrobial strategies such as the use of silver nanoparticles, antibiotics, and antimicrobial agents can be utilized to protect against infections. Therefore, the antimicrobial strategies besides the drug delivery applications of pHEMA were covered. With continuous research and advancement in science and technology, the outlook of pHEMA is promising as it will most certainly be utilized in more biomedical applications in the near future. The aim of this review was to bring together state-of-the-art research on pHEMA and their applications.

Mucoadhesive Nanoparticles for Drug Delivery to the Anterior Eye

While the use of topical drops for the delivery of drugs to the anterior of the eye is well accepted, it is far from efficient with as little as 5% of the drug instilled on the eye actually reaching the target tissue. The ability to prolong the residence time on the eye is desirable. Based on the acceptability of 2-hydroxyethyl methacrylate based polymers in contact lens applications, the current work focuses on the development of a poly(2-hydroxyethyl methacrylate (HEMA)) nanoparticle system. The particles were modified to allow for degradation and to permit mucoadhesion. Size and morphological analysis of the final polymer products showed that nano-sized, spherical particles were produced. FTIR spectra demonstrated that the nanoparticles comprised poly(HEMA) and that 3-(acrylamido)phenylboronic acid (3AAPBA), as a mucoadhesive, was successfully incorporated. Degradation of nanoparticles containing N,N′-bis(acryloyl)cystamine (BAC) after incubation with DL-dithiothreitol (DTT) was confirmed by a decrease in turbidity and through transmission electron microscopy (TEM). Nanoparticle mucoadhesion was shown through an in-vitro zeta potential analysis.

Design of an amphiphilic hyperbranched core/shell-type polymeric nanocarrier platform for drug delivery

An amphiphilic core/shell-type polymer-based drug carrier system (HPAE- PCL-b -MPEG), composed of hyperbranched poly(aminoester)-based polymer (HPAE) as the core building block and poly(ethylene glycol)-b - poly(ε-caprolactone) diblock polymers (MPEG-b -PCL) as the shell building block, was designed. The synthesized polymers were characterized with FTIR, 1 H NMR, 13 C NMR, and GPC analysis. Monodisperse HPAE-PCL-b - MPEG nanoparticles with dimensions of < 200 nm and polydispersity index of < 0.5 were prepared by nanoprecipitation method and characterized with SEM, particle size, and zeta potential analysis. 5-Fluorouracil was encapsulated within HPAE-PCL-b -MPEG nanoparticles. In vitro drug release profiles and cytotoxicity of blank and 5-fluorouracil-loaded nanoparticles were examined against the human colon cancer HCT116 cell line. All results suggest that HPAE-PCL-b - MPEG nanoparticles offer an alternative and effective drug nanocarrier system for drug delivery applications.

Nanostructured Chitosan-Based Biomaterials for Sustained and Colon-Specific Resveratrol Release

In the present work, we demonstrate the preparation of chitosan-based composites as vehicles of the natural occurring multi-drug resveratrol (RES). Such systems are endowed with potential therapeutic effects on inflammatory bowel diseases (IBD), such as Crohn's disease (CD) and ulcerative colitis, through the sustained colonic release of RES from long-lasting mucoadhesive drug depots. The loading of RES into nanoparticles (NPs) was optimized regarding two independent variables: RES/polymer ratio, and temperature. Twenty experiments were carried out and a Box⁻Behnken experimental design was used to evaluate the significance of these independent variables related to encapsulation efficiency (EE). The enhanced RES EE values were achieved in 24 h at 39 °C and at RES/polymer ratio of 0.75:1 w/w. Sizes and polydispersities of the optimized NPs were studied by dynamic light scattering (DLS). Chitosan (CTS) dispersions containing the RES-loaded NPs were ionically gelled with tricarballylic acid to yield CTS-NPs composites. Macro- and microscopic features (morphology and porosity studied by SEM and spreadability), thermal stability (studied by TGA), and release kinetics of the RES-loaded CTS-NPs were investigated. Release patterns in simulated colon conditions for 48 h displayed significant differences between the NPs (final cumulative drug release: 79⁻81%), and the CTS-NPs composites (29⁻34%).

An evaluation of crude palm oil (CPO) and tocotrienol rich fraction (TRF) of palm oil as percutaneous permeation enhancers using full-thickness human skin

The drawbacks associated with chemical skin permeation enhancers such as skin irritation and toxicity necessitated the research to focus on potential permeation enhancers with a perceived lower toxicity. Crude palm oil (CPO) is obtained by direct compression of the mesocarp of the fruit of the oil palm belonging to the genus Elaeis. In this research, CPO and tocotrienol-rich fraction (TRF) of palm oil were evaluated for the first time as skin permeation enhancers using full-thickness human skin. The in vitro permeation experiments were conducted using excised human skin mounted in static upright 'Franz-type' diffusion cells. The drugs selected to evaluate the enhancing effects of these palm oil derivatives were 5-fluorouracil, lidocaine and ibuprofen: compounds covering a wide range of Log p values. It was demonstrated that CPO and TRF were capable of enhancing the percutaneous permeation of drugs across full-thickness human skin in vitro. Both TRF and CPO were shown to significantly enhance the permeation of ibuprofen with flux values of 30.6 µg/cm² h and 23.0 µg/cm² h respectively, compared to the control with a flux of 16.2 µg/cm² h. The outcome of this research opens further scope for investigation on the transdermal penetration enhancement activity of pure compounds derived from palm oil.

The polycondensing temperature rather than time determines the degradation and drug release of poly(glycerol-sebacate) doped with 5-fluorouracil

Poly(glycerol-sebacate) (PGS) is an elastomeric biodegradable polyester that could be used as biodegradable drug carrier. We have previously prepared PGS implants doped with 5-fluorouracil (5-FU-PGSs) and found that 5-FU-PGSs exhibited an initial burst of 5-FU release during in vitro degradation. The synthesis temperature and time are two of the most important reaction conditions for polymer synthesis. Therefore, in order to establish a controllable drug-release manner, we prepared a series of 5-FU-PGS with 2% weight of 5-FU under synthesis conditions with different polycondensing temperature and time and characterized the infrared spectrum properties, in vitro degradation and drug release. Results showed that the polycondensing temperature determined the mechanical properties, degradation and drug release of 5-FU-PGSs. With the polycondensing temperature increasing, the elastic modulus and hardness of 5-FU-PGSs increased, and the mass loss and 5-FU release rate decreased. The polycondensing time had no significant influence on the mechanical property, degradation and drug release of 5-FU-PGSs. We suggest that the polycondensing temperature is the factor to control the drug-release manner.

Optimizing the release process and modelling of in vitro release data of cis-dichlorodiamminoplatinum (II) encapsulated into poly(2-hydroxyethyl methacrylate) nanocarriers

Drug encapsulated nanocarriers are vehicles to transport the drug molecules and release them at the immediate vicinity of the diseased sites. The aim of this study was to design poly (2-hydroxyethyl methacrylate) nanoparticles (PHEMANPs) as a swelling and diffusion controlled drug release system for achieving sustained release of (cis-dichlorodiamminoplatinum II) CDDP. The study undertakes designing and characterization of nanocarriers, optimization of drug encapsulation, and investigating release dynamics of the CDDP drug. PHEMANPs were prepared by suspension polymerization method followed by post loading of the CDDP onto the nanocarriers. The physicochemical and biopharmaceutical properties were evaluated by FTIR, TEM, FESEM, EDX, DLS, surface charge, water intake studies, in vitro cytotoxicity, protein adsorption and percent haemolysis. Chemical stability of the drug was assessed and in vitro release experiments were performed to optimize formulation by UV spectral analysis. The obtained cumulative release data were fitted to zero, first and Korsmeyer-Peppas kinetic models to gain insights into release kinetics and prevailing drug transport mechanisms. The successful encapsulation of CDDP was achieved in different PHEMANP formulations with maximum drug encapsulation efficiency of approx. 60% and the release kinetics was found to follow the Korsmeyer-Peppas model having non-Fickian mechanism. The results indicated that the CDDP can be formulated with a high payload of PHEMANPs which can serve as promising nanomedicine and help in achieving sustained delivery of drug for targeting tumour.

Investigation of magnetically controlled water intake behavior of Iron Oxide Impregnated Superparamagnetic Casein Nanoparticles (IOICNPs)

Iron oxide impregnated casein nanoparticles (IOICNPs) were prepared by in-situ precipitation of iron oxide within the casein matrix. The resulting iron oxide impregnated casein nanoparticles (IOICNPs) were characterized by Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), Vibrating sample magnetometer (VSM) and Raman spectroscopy. The FTIR analysis confirmed the impregnation of iron oxide into the casein matrix whereas XPS analysis indicated for complete oxidation of iron (II) to iron(III) as evident from the presence of the observed representative peaks of iron oxide. The nanoparticles were allowed to swell in phosphate buffer saline (PBS) and the influence of factors such as chemical composition of nanoparticles, pH and temperature of the swelling bath, and applied magnetic field was investigated on the water intake capacity of the nanoparticles. The prepared nanoparticles showed potential to function as a nanocarrier for possible applications in magnetically targeted delivery of anticancer drugs.

Preparation and characterization of molecularly imprinted poly(hydroxyethyl methacrylate) microspheres for sustained release of gatifloxacin

Molecularly imprinted poly(hydroxyethyl methacrylate) microspheres (PHEMA MIPMs) were prepared via precipitation polymerization in this article, using gatifloxacin (GFLX), hydroxyethyl methacrylate (HEMA), and ethylene glycol dimethacrylate (EGDMA) as template molecule, functional monomer and cross-linker, respectively. The effects of reaction medium, initial total monomers, cross-linker and molecular imprinting on the polymerization were investigated systematically. The interaction between GFLX and HEMA in pre-solution was studied by UV-Visible spectrophotometer, both size and morphology of products were characterized by a scanning electron microscope. When the total initial monomer concentration was 1 vol%, EGDMA content was 70 mol%, a group of uniform PHEMA MIPMs were prepared at different GFLX/MAA molar ratios, with diameter range from 2.06 ± 0.07 to 2.82 ± 0.20 μm. The results of drug loading and in vitro release experiments demonstrated that PHEMA MIPMs could achieve a higher GFLX loading content and a more acceptable sustained release than non-imprinted ones.

Synthesis and characterization of curcumin loaded polymer/lipid based nanoparticles and evaluation of their antitumor effects on MCF-7 cells

BACKGROUND

Hybrid materials are synthesized using hydrophilic polymer and lipids which ensure their long term systemic circulation through intravenous administration and enhance loading of hydrophobic drugs. The purpose of this study is to prepare, characterize and evaluate the in vitro efficacy of curcumin loaded poly-hydroxyethyl methacrylate/stearic acid nanoparticles in MCF-7.

METHODS

C-PSA-NPs, prepared using the emulsification-solvent evaporation method were characterized by dynamic laser scattering, SEM, AFM, FT-IR, X-ray diffraction, and TGA. The in vitro release behavior was observed in PBS pH7.4, the anticancer potential was analyzed by MTT assay, cell cycle and apoptosis studies were performed through flow cytometry. C-PSA-NPs drug localization and cancer cell morphological changes were analyzed in MCF-7 cell line.

RESULTS

C-PSA-NPs exhibited the mean particle size in the range of 184nm with no aggregation. The surface charge of the material was around -29.3mV. Thermal studies (TGA) and surface chemistry studies (FT-IR, XRD) showed the existence of drug curcumin in C-PSA-NPs. The MTT assay indicated higher anticancer properties and flow cytometry studies revealed that there were better apoptotic activity and maximum localization of C-PSA-NPs than curcumin.

CONCLUSIONS

Polymer lipid based drug delivery appeared as one of the advancements in drug delivery systems. Through the present study, a novel polymer lipid based nanocarrier delivery system loaded with curcumin was demonstrated as an effective and potential alternative method for tumor treatment in MCF-7 cell line.

GENERAL SIGNIFICANCE

C-PSA-NPs exhibited potent anticancer activity in MCF-7 cell line and it indicates that C-PSA-NPs are a suitable carrier for curcumin.

A poly(glycerol-sebacate-(5-fluorouracil-1-acetic acid)) polymer with potential use for cancer therapy

In this study, 5-fluorouracil-1-acetic acid was chemically conjugated with poly(glycerol-sebacate) (PGS) to form a unitary polymer poly(glycerol-sebacate- (5-fluorouracil-1-acetic acid)) (PGS-5-FU-CH2COOH). The structure, the in vitro antitumor activity of 5-FU-CH2COOH, the in vitro degradation, the drug release, and antitumor activity as well as the in vivo degradation and tissue biocompatibility of PGS-5-FU-CH2COOH were investigated. The 5-FU-CH2COOH inhibited HeLa (human cervical cancer cell line) and SGC-7901 (human gastric adenocarcinoma cell line) tumor cells with a half maximal inhibitory concentration (IC50) of 0.196 and 0.267 μM, respectively, after a 3-day incubation. The in vitro drug release profiles of PGS-5-FU-CH2COOH exhibited a biphasic release with an initial exponential phase in the first week and then the second constant linear phase. An in vitro antitumor assay of the PGS-5-FU-CH2COOH polymer showed significant cytotoxicity against tumor cells. The implanted PGS-5-FU-CH2COOH degraded completely in 1 month after implantation. The antitumor activity and improved drug release profile of PGS-5-FU-CH2COOH indicate its potential as an implantable polymer for cancer therapy.

Nanocrystalline hydroxyapatite and zinc-doped hydroxyapatite as carrier material for controlled delivery of ciprofloxacin

In bone disorders infections are common. The concentration of majority of antibiotics is very low in the bone tissue. A high local dose can be obtained from the ciprofloxacin-loaded hydroxyapatite nanoparticles. The present study is aimed at developing the use of hydroxyapatite and zinc-doped hydroxyapatite nanoparticles as a carrier for ciprofloxacin drug delivery system. The ciprofloxacin-loaded hydroxyapatite and zinc-doped hydroxyapatite have a good antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus. Hydroxyapatite and zinc-doped hydroxyapatite were prepared and characterized using X-ray diffraction, Transmission electron microscopy and inductively coupled plasma optical emission spectrometry. They were loaded with ciprofloxacin using optimized drug loading parameters. Drug loading, in vitro drug release and antimicrobial activity were analyzed. The influence of zinc on the controlled release of ciprofloxacin was analyzed. The results show that the presence of zinc increases the drug release percentage and that the drug was released in a controlled manner.

Vitamin E triggers poly(2-hydroxyethyl methacrylate) (PHEMA) embolic potential: a proposed application for endovascular surgery

Poly(2-hydroxyethyl methacrylate) (PHEMA) is a biocompatible polymer used as embolizing agent for endovascular surgery. Blending of PHEMA with a hydrophobic and anti-oxidant agent, Vitamin E (Vit.E, 0.1-10%, w/v), modified PHEMA's haemocombatibility, evaluated measuring wettability, plasma protein adsorption along with whole blood coagulation time. The presence of Vit.E increases PHEMA's hydrophobicity and plasma protein adsorption (in particular albumin and Immunoglobulin G), while it also accelerates blood clot formation. These effects are developed due to a combination of issues such as surface hydrophobicity and plasma protein adsorption induced by the presence of Vit.E, suggesting that Vit.E blending could improve the use of PHEMA as embolizing agent.

Drug delivery systems: Advanced technologies potentially applicable in personalized treatments

Advanced drug delivery systems (DDS) present indubitable benefits for drug administration. Over the past three decades, new approaches have been suggested for the development of novel carriers for drug delivery. In this review, we describe general concepts and emerging research in this field based on multidisciplinary approaches aimed at creating personalized treatment for a broad range of highly prevalent diseases (e.g., cancer and diabetes). This review is composed of two parts. The first part provides an overview on currently available drug delivery technologies including a brief history on the development of these systems and some of the research strategies applied. The second part provides information about the most advanced drug delivery devices using stimuli-responsive polymers. Their synthesis using controlled-living radical polymerization strategy is described. In a near future it is predictable the appearance of new effective tailor-made DDS, resulting from knowledge of different interdisciplinary sciences, in a perspective of creating personalized medical solutions.