pH-Dependent Release of Insulin from Layer-by-Layer-Deposited Polyelectrolyte Microcapsules

Abstract

Insulin-containing microcapsules were prepared by a layer-by-layer (LbL) deposition of poly(allylamine hydrochloride) (PAH) and polyanions, such as poly(styrenesulfonate) (PSS), poly(vinyl sulfate) (PVS), and dextran sulfate (DS) on insulin-containing calcium carbonate (CaCO3) microparticles. The CaCO3 core was dissolved in diluted HCl solution to obtain insulin-containing hollow microcapsules. The microcapsules were characterized by scanning electron microscope (SEM) and atomic force microscope (AFM) images and ζ-potential. The release of insulin from the microcapsules was faster at pH 9.0 and 7.4 than in acidic solutions due to the different charge density of PAH. In addition, insulin release was suppressed when the microcapsules were constructed using PAH with a lower molecular weight, probably owing to a thicker shell of the microcapsules. The results suggested a potential use of the insulin-containing microcapsules for developing insulin delivery systems.

Layer‐by‐Layer Assembly of κ‐Casein Amyloid Fibrils for the Preparation of Hollow Microcapsules

“…In contrast, spheres prepared with the LbL‐assembled (κCF/PAA) n were ruptured after dissolution in the HF solution. Figure b shows the flattened balloon‐shaped hollow microcapsules presenting the successful preparation of hollow microcapsules . The AFM plane images presented in Figure b indicate the overwrapped thickness of 49.6 nm for two (κCF/PSS) 6.5 shells.…”

New strategy of controlled, stepwise release from novel MBioF and its potential application for drug delivery systems

“…In the literature, there are examples of doxorubicin (DOX) drug delivery systems being pH dependent. (Seib et al 2013;Zou et al 2017;Yoshida et al 2015). However the stepwise release after lowering the pH value results from unique properties of DOX itself and cannot be applied to other cytostatic drugs.…”

“…Thus, its better solubility in acidic solutions was expected. The gradual insulin release from microcapsules prepared by a layer-bylayer deposition of poly(allylamine hydrochloride) and polyanions, such as poly(styrene sulfonate), poly(vinyl sulfate), and dextran sulfate was tested by Yoshida et al (2015) The authors observed a faster release in basic environment than in acidic solutions and explained the phenomena by a different charge density of poly(allylamine hydrochloride) which is unstable in solutions of higher pH.…”

“…The above mentioned methods can be divided into two main groups reflecting the drugs (Seib et al 2013;Zou et al 2017;Yang et al 2016;Tan et al 2016) or matrix solubility (Yoshida et al 2015;Gao et al 2017). Among the latter, there are no studies that would report the matrix dissolution products to be fully biocompatible.…”

Untitled

“…However, LbL assembly on NPs surface incorporating drug has not been extensively studied. In other LbL-based techniques, NPs are coated with PE and subsequently, the core is sacrificed to create a hollow core inside which drugs are loaded to form drug -loaded NPs 26 . The loading capacity of the drug in hollowed out NPs with LbL coating is controlled by the size of the core NPs.…”