•We report biocompatible and mechanically stable microspheres based on PPHOSs/PMMA for hydrophilic drug release application.•The microspheres showed porosity, which was increased with drug release and degradation time.•The microspheres meet the basic requirement of in vivo drug release application for skeleton diseases.Drug delivery system is referred as an approach to deliver the therapeutic agents to the target site safely in order to achieve the maximum therapeutic effects. In this perspective, synthesis of three new polyphosphazenes and their blend fabrication system with poly(methyl methacrylate) is described and characterized with 1H NMR, 31P NMR, GPC and DSC. Furthermore, these novel blends were used to fabricate microspheres and evaluated for sustain release of hydrophilic drug (aspirin as model drug). Microspheres of the two blends showed excellent encapsulation efficacy (about 93%), controlled burst release (2.3% to 7.93%) and exhibited sustain in vitro drug release (13.44% to 32.77%) up to 218 h. At physiological conditions, the surface degradation of microspheres and diffusion process controlled the drug release sustainability. Furthermore, it was found that the degree of porosity was increased with degradation and the resulting porous network was responsible for water retention inside the microspheres. The percentage water retention was found to be interrelated with degradation time and percentage drug release.

Currently, most of administered anti-cancer drugs are low molecular weight compounds (as compare to polymers) and hydrophobic in nature. Such small molecular anti-cancer drugs possess fast clearance rate from the blood circulating system and have toxic side effects. Poly(organophosphazenes) have wide range of biomedical applications owing good biocompatibility, sustainability and degradability into non-toxic by-products. So, in this review, we have carefully selected such poly(organophosphazenes), which proved to be good anti-cancer drug carriers because of overcoming crucial issues related to the administration of anti-cancer drugs i.e. poor hydrophilicity, lack of cancer cells specificity, and fast clearance rate from blood circulating system. Thence, the main focus of this review is to highlight the advancement that have been achieved in the synthesis of poly(organophosphazenes) and their application in anti-cancer drug delivery system (DDS).

The star-shaped poly(ε-caprolactone)-b-poly(2-(dimethylamino)ethyl methacrylate) (HPs-Star-PCL-b-PDMAEMA) was synthesized by ring-opening polymerization and reversible addition–fragmentation chain transfer (RAFT) polymerization. Star-shaped polycaprolactones (HPs-Star-PCL) were synthesized by the bulk polymerization of ε-caprolactone (CL) with a hyperbranched polyester initiator and tin 2-ethylhexanoate as a catalyst. The number-average molecular weight of these polymers linearly increased with the increase of the molar ratio of CL to hyperbranched initiator. HPs-Star-PCL was converted into a HPs-star-PCL-RAFT by an esterification of HPs-Star-PCL and 4-cyanopentanoic acid dithiobenzoate. Star amphiphilic block copolymer HPs-Star-PCL-b-PDMAEMA was obtained via RAFT polymerization of 2-(dimethylamino)ethyl methacrylate (DMAEMA). The molecular weight distribution of HPs-Star-PCL-b-PDMAEMA was narrow. Furthermore, the micellar properties of HPs-Star-PCL-b-PDMAEMA in water were studied at various temperatures and pH values by means of dynamic light scattering (DLS). The results indicated that the star copolymers had the pH- and temperature-responsive properties. The release behaviors of model drug aspirin from the star polymer indicated that the rate of drug release could be effectively controlled by pH value and temperature.(HPs-Star-PCL-b-PDMAEMA) was synthesized by ring-opening polymerization and RAFT polymerization.

Two novel ferrocene-based compounds glycidyl ester of ferrocene carboxylate (GEFC) and 1,3-diferrocenecarboxylic acid diacylglycerol (DFCDG) were synthesized and characterized by 1H NMR and mass spectrum. The influence of some factors, namely, solvent type, potential scan rate, electrolyte concentration and [Fe] unit concentration, on the electrochemical behaviors of two novel ferrocene-based compounds was investigated, and the mechanism of the electrode processes was studied. Finally, two compounds were applied to sense the H2PO4− by cyclic voltammetry (CV) method and it was found that the DFCDG with a symmetric structure which was synthesized through ring opening reaction of ferrocene carboxylate and GEFC showed stronger interaction with the H2PO4− than GEFC.

A novel ferrocenyl anion receptor N,N,N,N-(dimethyl, ethyl, ferrocenecarboxylic amidodimethylene) ammonium fluoborate 2 with multiple binding sites was synthesized. Its anion recognition behaviors were investigated by CV, 1H NMR and UV−vis spectrum. It was found that the combination of two interactions enforced the anion binding ability and the binding selectivity of 2 to phosphate anion. The effects of scan rate on the CV curves of 2 with phosphate were also investigated. In different scan rate, the CV curves kept stable which indicated the strong binding between 2 and phosphate. According to relationships of peak potential, peak currents and scan rate of 2 binding with phosphate, the kinetic parameters of electrode process such as diffusion coefficient Dapp, surface transfer coefficient αnα, and standard rate constant k0 were calculated.

Comb-like amphiphilic block copolymers of maleic anhydride (MA) and stearyl methacrylate (SMA) were prepared through the reversible-addition-fragmentation-transfer polymerization. The resultant copolymers were characterized by gel permeation chromatograph and 1H NMR. The aggregation behaviors of P(MA-alt-SMA)-b-PSMA were investigated in tetrahydrofuran/water. It is of great interest that the aggregates with different morphologies and dimensions could be obtained by adjusting the polymer concentration, water content, and pH. The dimension and structure of these aggregates were investigated by transmission electron microscopy and dynamic light scattering. The effect of the copolymer–solvent interaction on these aggregations was discussed.