Core–shell biocompatible polyurethane nanocapsules obtained by interfacial step polymerisation in miniemulsion

Polyelectrolyte hydrogel capsules as stabilizers for reconfigurable complex emulsions

Polyelectrolyte capsules stabilize biphasic oil droplets while preserving droplet reconfigurability in the presence of surfactants.

Magnetic Polyurea Nano-Capsules Synthesized via Interfacial Polymerization in Inverse Nano-Emulsion

Polyurea (PU) nano-capsules have received voluminous interest in various fields due to their biocompatibility, high mechanical properties, and surface functionality. By incorporating magnetic nanoparticle (MNPs) into the polyurea system, the attributes of both PU and MNPs can be combined. In this work, we describe a facile and quick method for preparing magnetic polyurea nano-capsules. Encapsulation of ionic liquid-modified magnetite nanoparticles (MNPs), with polyurea nano-capsules (PU NCs) having an average size of 5–20 nm was carried out through interfacial polycondensation between amine and isocyanate monomers in inverse nano-emulsion (water-in-oil). The desired magnetic PU NCs were obtained utilizing toluene and triple-distilled water as continuous and dispersed phases respectively, polymeric non-ionic surfactant cetyl polyethyleneglycol/polypropyleneglycol-10/1 dimethicone (ABIL EM 90), diethylenetriamine, ethylenediamine diphenylmethane-4,4′-diisocyanate, and various percentages of the ionic liquid-modified MNPs. High loading of the ionic liquid-modified MNPs up to 11 wt% with respect to the dispersed aqueous phase was encapsulated. The magnetic PU NCs were probed using various analytical instruments including electron microscopy, infrared spectroscopy, X-ray diffraction, and nuclear magnetic spectroscopy. This unequivocally manifested the successful synthesis of core-shell polyurea nano-capsules even without utilizing osmotic pressure agents, and confirmed the presence of high loading of MNPs in the core.

Natural biodegradable polymers based nano-formulations for drug delivery: A review

Nanomedicines are now considered as the new-generation medication in the current era mainly because of their features related to nano size. The efficacy of many drugs in their micro/macro formulations is shown to have poor bioavailability and pharmacokinetics after oral administration. To overcome this predicament, use of natural/synthetic biodegradable polymeric nanoparticles (NPs) have gained prominence in the field of nanomedicine for targeted drug delivery to improve biocompatibility, bioavailability, safety, enhanced permeability, better retention time and lower toxicity. For drug delivery, it is essential to have biodegradable nanoparticle formulations for safe and efficient transport and release of drug at the intended site. Moreover, depending on the target organ, a suitable biodegradable polymer can be selected as the drug-carrier for target specific as well as for sustained drug delivery. The aim of this review is to present the current status and scope of natural biodegradable polymers as well as some emerging polymers with special characteristics as suitable carriers for drug delivery applications. The most widely preferred preparation methods are discussed along with their characterization using different analytical techniques. Further, the review highlights significant features of methods developed using natural polymers for drug entrapment and release studies.

Preparation of polyurea microcapsules containing phase change materials in a rotating packed bed

Polyurea microcapsules containing a phase change material with a much shorter preparation time, good morphology, high actual core content and encapsulation efficiency were firstly synthesized through interfacial polymerization in a rotating packed bed.

Aerosol Delivery of siRNA to the Lungs. Part 2: Nanocarrier-based Delivery Systems

In this article, applications of engineered nanoparticles containing siRNA for inhalation delivery are reviewed and discussed. Diseases with identified protein malfunctions may be mitigated through the use of well-designed siRNA therapeutics. The inhalation route of administration provides local delivery of siRNA therapeutics to the lungs for various pulmonary diseases. A siRNA delivery system can be used to overcome the barriers of pulmonary delivery, such as anatomical barriers, mucociliary clearance, cough clearance, and alveolar macrophage clearance. Apart from naked siRNA aerosol delivery, previously studied siRNA carrier systems include those of lipidic, polymeric, peptide, or inorganic origin. These delivery systems can achieve pulmonary delivery through the generation of an aerosol via an inhaler or nebulizer. The preparation methodologies for these siRNA nanocarrier systems will be discussed herein. The use of inhalable nanocarrier siRNA delivery systems have barriers to their effective delivery, but overcoming these constraints while formulating a safe and effective delivery system will offer unique advances to the field of inhaled medicine.

Preparation of elastic polyurethane microcapsules using CaCO3 microparticles as templates for hydrophobic substances loading

Elastic polyurethane (PU) microcapsules were fabricated via a simple and well controllable adsorption and crosslinking method on porous CaCO₃ templates in organic solvent.

Microencapsulation of 2-octylcyanoacrylate tissue adhesive for self-healing acrylic bone cement

Here, we report the first phase of developing self-healing acrylic bone cement: the preparation and characterization of polyurethane (PUR) microcapsules containing a medical cyanoacrylate tissue adhesive. Capsules were prepared by interfacial polymerization of a toluene-2,4-diisocyanate-based polyurethane prepolymer with 1,4-butanediol to encapsulate 2-octylcyanoacrylate (OCA). Various capsule characteristics, including: resultant morphology, average size and size distribution, shell thickness, content and reactivity of encapsulated agent, and shelf life are investigated and their reliance on solvent type and amount, surfactant type and amount, temperature, pH, agitation rate, reaction time, and mode of addition of the oil phase to the aqueous phase are presented. Capsules had average diameters ranging from 74 to 222 μm and average shell thicknesses ranging from 1.5 to 6 μm. The capsule content was determined via thermogravimetric analysis and subsequent analysis of the capsules following up to 8 weeks storage revealed minimal loss of core contents. Mechanical testing of OCA-containing capsules showed individual capsules withstood compressive forces up to a few tenths of Newtons, and the contents released from crushed capsules generated tensile adhesive forces of a few Newtons. Capsules were successfully mixed into the poly(methyl methacrylate) bone cement, surviving the mixing process, exposure to methyl methacrylate monomer, and the resulting exothermic matrix curing.

Facile and Rapid Access to Glyconanocapsules by CuAAC Interfacial Polyaddition in Miniemulsion Conditions

Glyconanocapsules with a biocompatible oily core have been successfully prepared by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) interfacial step growth polymerization between 6,6'-diazido-6,6'-dideoxysucrose and bis(propargyloxy)butane in oil-in-water miniemulsion conditions. Optimization of the interfacial polymerization process in dispersed medium afforded the rapid and reproducible preparation of stable monodispersed glyconanocapsules having a diameter around 200 nm.

Miniemulsion polymerization as a versatile tool for the synthesis of functionalized polymers

The miniemulsion technique is a particular case in the family of heterophase polymerizations, which allows the formation of functionalized polymers by polymerization or modification of polymers in stable nanodroplets. We present here an overview of the different polymer syntheses within the miniemulsion droplets as reported in the literature, and of the current trends in the field.

Macromolecular surfactants for miniemulsion polymerization

The use of polymeric surfactants as stabilizers in miniemulsion polymerization was reviewed. The structural characteristics of reported polymeric surfactants were detailed and compared. The concept of multi-functional polymeric surfactants was evidenced. The specificities brought by polymeric surfactants in the process of miniemulsion polymerization in comparison to molecular surfactants were analysed for the stability of the initial monomer emulsion, polymerization kinetics and characteristics of the obtained latexes. The contribution of polymeric surfactants to the control of the characteristics of the obtained nanoparticles was detailed with regard to the nature of the core material and to the surface coverage. Polymeric surfactants can be seen as powerful tools for the design of original nanoparticles. On the basis of the available data, possible research topics are suggested.