Release of Aspirin from Biodegradable Polyesterurethane Networks

Abstract

In this paper, the release of model drug aspirin (ASP) from biodegradable polyesterurethane networks was studied. Poly(D,L-lactide-co-glycolide)urethane (PULG) networks were prepared from hydroxyl telechelic star-shaped oligo(D,L-lactide-co-glycolide) coupled with 1,6-diisocyanate-2,2,4-trimethylhexane and 1,6-diisocyanate-2,4,4-trimethylhexane or isophorone diisocyanate. PULG networks turned from transparent to opaque after ASP loading. PULG networks with lower crosslinking density always resulted in higher drug loaded content. The results of differential scanning calorimetry (DSC) and scanning electron microscope (SEM) measurements demonstrated that ASP was uniformly distributed in the networks. The drug release courses of ASP from PULG networks in phosphate buffered saline pH = 7.0 at 37 °C could be divided into three stages. Firstly, ASP release was at approximately uniform rate from PULG networks; Secondly, the release rate obviously increased for the degradation of the PULG networks; Thirdly, the release rate decreased gradually because most of the ASP had diffused out of the PULG networks. The crosslinking density of polyesterurethane networks also affected drug release rate. The in vitro release test revealed that ASP accelerated the degradation process of PULG, which exhibited a typical erosion-controlled release mechanism.

Synthesis of Hyperbranched Polymers with High Molecular Weight in the Homopolymerization of Polymerizable Trithiocarbonate Transfer Agent without Thermal Initiator

“…In the past few decades, both dendrimers and hyperbranched polymers are popularly studied and proposed as promising types of nanostructured polymers due to their attractive structural features, including compact three-dimensional structures, cavernous interior, and large number of peripheral groups. − Unlike dendrimers, hyperbranched polymers can be easily synthesized in a one-pot polymerization following several different techniques: polymerization of AB m ( m ≥ 2) monomers (with or without the use of multifunctional B f core), − copolymerization of A n and B m monomers (e.g., A 2 + B 3 ), − polymerization of divinyl or multivinyl cross-linkers (in the presence or absence of monovinyl monomers), − and self-condensing vinyl polymerization (SCVP) of polymerizable initiators, often known as inimers . The last technique requires the use of controlled polymerization methods, such as controlled radical polymerization (CRP), − living ionic polymerization, − ring-opening metathesis polymerization (ROMP), and group transfer polymerization …”

Electrospun poly(N-isopropylacrylamide)/poly(caprolactone)-based polyurethane nanofibers as drug carriers and temperature-controlled release

“…19,20 Biodegradable PCL and IPDI can synthesize non-toxic and biodegradable polyurethanes (PU) biomaterials, [21][22][23] with better biocompatibility than other synthetic polymers because of the micro-phase separated structures. 24 Nifedipine (NIF), a hypertension and angina drug, would induce detrimental effects on patients with an excessive therapeutic dose. Therefore, it is desirable to develop controlled release dosage forms of NIF to reduce the side effects.…”

Shape memory materials and 4D printing in pharmaceutics

“…With the idea of broadening the range of available multifunctional materials -i.e. polymers showing different independent functionalities -and to tailor them to the desired application, new polymers were purposely synthetized [64,72,[74][75][76]79,[113][114][115][116][117][118][119][120].…”