Synthesis of biocompatible poly(ε-caprolactone)-block-poly(propylene adipate) copolymers appropriate for drug nanoencapsulation in the form of core-shell nanoparticles

Abstract

Poly(propylene adipate)-block-poly(ε-caprolactone) copolymers were synthesized using a combination of polycondensation and ring-opening polymerization of ε-caprolactone in the presence of poly(propylene adipate). Gel permeation chromatography was used for molecular weight determination, whereas hydrogen-1 nuclear magnetic resonance and carbon-13 nuclear magnetic resonance spectroscopy were employed for copolymer characterization and composition evaluation. The copolymers were found to be block while their composition was similar to the feeding ratio. They formed semicrystalline structures, while only poly(ε-caprolactone) formed crystals, as shown by wide angle X-ray diffraction. Differential scanning calorimetry data suggest that the melting point and heat of fusion of copolymers decreased by increasing the poly(propylene adipate) amount. The synthesized polymers exhibited low cytotoxicity and were used to encapsulate desferrioxamine, an iron-chelating drug. The desferrioxamine nanoparticles were self-assembled into core shell structures, had mean particle size ,250 nm, and the drug remained in crystalline form. Further studies revealed that the dissolution rate was mainly related to the melting temperature, as well as to the degree of crystallinity of copolymers.

Synthesis, Properties, and Enzymatic Hydrolysis of Poly(lactic acid)-co-Poly(propylene adipate) Block Copolymers Prepared by Reactive Extrusion

“…Its melting point (T m ) was observed at 41 °C, and its T g after quenching was −57 °C. These values are consistent with previous reports [ 33 , 34 , 47 , 51 , 52 , 53 ]. The quenched PPAd also showed cold crystallization at T cc = 6.8 °C and melt crystallization at T c = −10.6 °C.…”

“…PPAd (Figure 4a) was received semicrystalline, as witnessed by its melting during the 1st heating scan. Its melting point (T m ) was observed at 41 • C, and its T g after quenching was −57 • C. These values are consistent with previous reports [33,34,47,[51][52][53]. The quenched PPAd also showed cold crystallization at T cc = 6.8 • C and melt crystallization at T c = −10.6 • C. PPAd exhibited a multiple melting behavior, since a secondary melting peak is recorded in its reheating scans at about 30 • C, right after the end of cold crystallization.…”

A Combined Computational and Experimental Study on the Polymerization of ε-Caprolactone

“…The δ 3.65 ppm (H-D, triplet, n J H–H = 6.84 Hz) was assigned to the −CH 2 OH ending group. These signals are in agreement with the literature. , The total areas of the signals were normalized, and the monomer conversion and the molecular weight were calculated by integrated area ratio as follows. The monomer conversion was determined according to the integrated area ratio of the signal at 4.23 ppm (−CH 2 O−) with the corresponding signal of the polymer at 4.06 ppm .…”

Preparation and optimization of polymeric micelles as an oral drug delivery system for deferoxamine mesylate: in vitro and ex vivo studies

“…This increases DFO residence time and reduces dosing frequency. DFO-loaded micelles prepared in this study significantly decreased release rate of DFO in comparison with free drug which is more favorable than some DFO-loaded nanoparticles such as poly(ɛ-caprolactone)-bloack-poly(propylene adipate) that showed 100% DFO release during 12 h (45). Based on regression analysis, in SGF, the correlation between polymer type and D 2 % was significant and polymeric micellar drug delivery systems containing poloxamer ® showed higher D 2 %.…”