Novel Castor Oil‐Derived Block Copolymers as Promising Candidates for Biological Applications: Biorelevant and Biocompatible

Abstract

The castor oil‐derived fatty acid (thioether‐containing ω‐hydroxyacid) is obtained using the UV‐catalyzed thiol‐Michael addition and is used for the first time as a monomer, for the development of biorelevant copolymers based on ε‐caprolactone, methoxy‐poly(ethylene glycol), and poly(ethylene glycol). Proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, and size exclusion chromatography, confirm the successful synthesis of diblock and triblock copolymers with very narrow molecular weight distributions. X‐ray diffractometry, polarizing light microscopy, and differential scanning calorimetry, suggest that crystallization of the crystalline block chains is restricted within the microphase‐separated morphology and that it is strongly affected by the competition between the two semicrystalline blocks. Moreover, thermogravimetric analysis reveals that the thermal properties of the copolymers are intermediate between those of their parent homopolymers. Regardless of their block composition, the biorelevant copolyesters do not exhibit apparent cytotoxicity, according to the (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) (MTT) and fluorescence microscopy assays.

Amphiphilic Block Copolymer Microspheres Derived from Castor Oil, Poly(ε-carpolactone), and Poly(ethylene glycol): Preparation, Characterization and Application in Naltrexone Drug Delivery

“…NLX showed an endothermic peak near 177 °C due to its melting point [ 32 ], while for the NLX-loaded microspheres, endothermic peaks were not recorded, suggesting that the drug was encapsulated in the amorphous state and that it was distributed in the polymer matrix. In agreement with results of previous DSC studies [ 17 ], the endothermic peaks of TEHA-b-PCL, TEHA-b-mPEG and TEHA-b-PEG-b-TEHA were recorded at 51.5, 48.2–67.1 (double peak) and 54.7–73.7 °C (double peak), respectively.…”

“…As shown, TEHA-b-PCL has one multiple peak at 2.30 ppm which corresponds to the –CH 2 CO– protons in PCL and TEHA units (H 4 , 6 ), and two triple peaks at 2.55 and 2.75 ppm, which can be assigned to the methylene protons linked to the sulfur atom (–CH 2 –S–) of TEHA block (H 2 , H 3 ) ( Scheme 1 ii). More importantly, in the spectrum of TEHA-b-PCL, the total conversion of the thioether functional groups was confirmed by the existence of shifts typical of –CH 2 –OH and CH 2 –O– proton signals at 4.20 and 4.05 ppm, respectively [ 17 ].…”

“…However, there might be several ways to still further enhance the drug delivery potential of ABCs-based microspheres. We have recently described the use of the castor-oil derivative TEHA, for the development of novel amphiphilic AB type (diblock) and ABA type (triblock) copolymers [ 17 ]. Such di/tri-block copolymers can be efficiently synthesized via the combination of a UV light-initiated thiol-ene “click” reaction and the following copolymerization of TEHA with ε-caprolactone (ε-CL), mPEG, or PEG.…”

Paclitaxel Magnetic Core–Shell Nanoparticles Based on Poly(lactic acid) Semitelechelic Novel Block Copolymers for Combined Hyperthermia and Chemotherapy Treatment of Cancer

“…The calculated number-based average molecular weights of copolymers are in agreement with the initial feed ratios and were found to be 12,200, 29,000, 45,800 and 86,200 for 1/5, 1/50, 1/70 and 1/140 TEHA to PDLLA ratios, respectively. As can be seen, by increasing TEHA content the Mn is reduced since TEHA (due to its hydroxyl groups) acts as initiator for ring opening polymerization of cyclic oligomers like d , l -lactide [38,42]. The greater the number of these groups the lower the molecular weight of produced copolymers, and hence, the TEHA-co-PDLLA 1/5 copolymer with the highest TEHA content has the lowest molecular weight compared to the rest copolymers.…”

“…TEHA was synthesized based on a previously published UV-irradiation method [37,38]. In brief, 10-undecenoicacid (15 g, 81 mmol) and 2-mercaptoethanol (6.36 g, 81 mmol) was irradiated in dichloromethane solution at λ = 365 nm in the presence of DMPA (2% TEHA/initiator molar ratio) as photo-initiator.…”