Synthesis and degradation of poly (alkyl α‐cyanoacrylates)

Abstract

SynopsisI n order to study structure-tissue reactivity relationships arid ultimately develop a less necrotizing adhesive, this laboratory undertook a study of the synthesis and degradation of the homologous series of a-cyanoacrylate monomers and polymers. A method for synthesizing high purity cyanoacrylates and some of their chemical and physical properties are presented. In vitro kinetics studies under heterogeneous and homogeneous conditions indicate that cyanoacrylate polymers degrade by hydrolytic scission of the polymer chain. The products resulting from such a scission are formaldehyde (positively identified by derivative formation) and ultimately an alkyl cyanoacetate. As the homologous series is ascended, the rate of degradation under neutral conditions decreases. In homogeneous solution, under alkaline conditions, the rate of degradation is considerably higher than under neutral conditions and the rates obtained with the methyl to the butyl derivative are of the same order. A proposed mechanism of degradation is presented. Medical evaluation has indicated that as the homologous series is ascended, the greater the tissue tolerance to the monomers and polymers. The relevance of the results of the in vitro studies to this medical finding is presented.

Pharmacokinetic parameters and tissue distribution of magnetic Fe3O4 nanoparticles in mice

“…It is likely that utilization of Fe 3 O 4 MNPs as drug carriers may overcome the physiologic limitations of drug transport by capillary barriers. 17 Currently, the mechanism by which nanoparticles traverse the barrier is unclear. 18 Although iron oxide nanoparticles are known to be well tolerated by the body and degrade with time, 19 it is worthwhile verifying whether the structure of Fe 3 O 4 MNPs changes after digestion and absorption through the intestine.…”

Reversion of multidrug resistance with polyalkylcyanoacrylate nanoparticles: towards a mechanism of action

“…In an aqueous medium, and especially in biological fluids, the degradation of PACA nanoparticles is thought to result from solubilization of the polymer because of hydrolysis of lateral ester bonds (Leonard et al, 1966). Indeed, such hydrolysis leads to the appearance of carboxylic groups.…”

Pharmacokinetics on a microscale: visualizing Cy5-labeled oligonucleotide release from poly(n-butylcyanoacrylate) nanocapsules in cells

“…In addition to the above, a rapid depolymerizationrepolymerization mechanism described by Ryan et al degrades PBCA by base-induced depolymerization, yielding lower molecular weight oligomers 26 ( Figure S7), and an alternative mechanism based on the inverse Knoevenagel reaction has also proposed. 27 Lenaerts et al have shown that this route of degradation played a marginal role when compared with the enzymatic route of degradation. 28 The influence of pH on degradation of poly(alkylcyanoacrylates) has also been studied in detail, eg, in the work of Scherer et al 25 The degradation rate increased with increasing pH; however, after uptake in cells via the endocytotic pathway, the pH will decrease from early endosomes to lysosomes, making this route of degradation less likely.…”