Stearic Acid-Coated Chitosan-Based Interpenetrating Polymer Network Microspheres: Controlled Release Characteristics

Abstract

Novel pH-sensitive stearic acid-coated interpenetrating polymer network (IPN) blend microspheres of chitosan and gelatin were prepared by the emulsion cross-linking method using glutaraldehyde for the controlled release (CR) of isoniazid (INH), an antituberculosis drug. Coated as well as uncoated microspheres were developed and characterized by Fourier transform infrared (FTIR) to understand the chemical interactions and formation of the IPN blend structure as well as to confirm successful coating with the stearic acid. X-ray diffraction (XRD) indicated the distribution of INH, while differential scanning calorimetry (DSC) was used for investigating the thermal stability of the IPN blend matrices. Scanning electron microscopy (SEM) was used to distinguish between the morphologies of coated and uncoated microspheres. Coated microspheres were produced in the size range of 52 μm down to 502 nm with encapsulation efficiencies of 65−78%. Equilibrium swelling was studied in pH 1.2 and pH 7.4 buffer media, and the in vitro drug release showed the dependence of drug release on the cross-linking, blend ratio of the IPN matrix as well as stearic acid coating. The variations in the IPN blend ratio and cross-link density controlled the drug release up to 30 h, but the coated microspheres could reduce the burst release in the gastric stomach media, while enhancing in intestinal pH 7.4 media.

The design of pH-sensitive chitosan-based formulations for gastrointestinal delivery

“…Utilization of coating materials such as stearic acid on the surfaces of chitosan-based PECs could further reduce the burst release in the gastric media. However, stearic acid does not seem to be stable as a coating matrix in alkaline media because of the ionization; thereby, the release of loaded isoniazid-coated formulations in alkaline media is higher than the uncoated formulation [36]. An example of the pH-dependent controlled drug release manner of the stearic-acid-coated formulation is depicted in Fig.…”

Development of Calcium Carbonate Double-Coated with Chitosan-Adipic Acid as a Promising Antibacterial Filler

“…These peaks were assigned to C-H stretching vibration of -CH 2 groups and indicated that adipic acid reacted with CaCO 3 . In the case of CAC(e), compared with the spectrum of chitosan and adipic acid-coated CaCO 3 , the peak shifted from 1652 cm -1 to 1638 cm--1 and an extra carboxylate anion band appeared at 1560 cm -1 , indicating electrostatic interactions between adipic acid and chitosan (27). It is reasonable to conclude that chitosan was crosslinked with adipic acid by ionic interactions (29,30) and successfully coated on adipic acid modified CaCO 3 .…”

“…Figure 1 shows FT-IR spectra of chitosan (a), adipic acid (b), naked CaCO 3 (c), adipic acid-coated CaCO 3 (d), and CAC (e). In the case of chitosan (a), a broad band observed at 3452 cm -1 can be assigned to the stretching vibrations of O-H and N-H (26), while the band at 1652 cm -1 represents the presence of the carbonyl of the amide group stretching vibrations (27). In the spectrum of CaCO 3 (c), the peaks appearing at 1431 and 874 cm -1 were attributed to asymmetric C-O stretching and out-of-plane deformation of CO 3 (28).…”

Adsorption and Diffusion Characteristics of 2-Naphthol from Aqueous Media by Chitosan-ENR Biocomposites

“…. The deviation of n value below indicated that it can also be due to the complexity of the biocomposites system with a high heterogeneity (Angadi et al 2011).…”