Methacrylic acid-co-butylmethacrylate copolymers: design, characterization and evaluation as encapsulating material for colon targeted formulations

Abstract

Hydrophilic monomer methacrylic acid was copolymerized with hydrophobic monomer butylmethacrylate in different molar ratio, using AIBNfree radical initiator. Successful polymerization was confirmed by FTIR and 1 H NMR, while DSC and XRD revealed the amorphous nature of the polymers. Copolymers were highly hemocompatible. The polymers showed pH-dependent swelling and erosion which increased with increase in pH. As the amount of methacrylic acid increased, the swelling and erosion also increased. Polymers were used for the microencapsulation of a model anti-inflammatory drug, aceclofenac by an oil-in-oil solvent evaporation method. Microparticles were characterized using FTIR, XRD, DSC, and SEM analysis. The negatively charged particles were almost spherical in shape. The drug release was best explained by zero-order kinetics with anomalous release mechanism. Less than 1% of drug was released at pH 1.2 while the bulk of the drug load was released at pH 6.8 or above, confirming the colon-targeting nature. The microparticles showed significant lowering in myeloperoxidase activity in trinitrobenzene sulfonic acidinduced colitis rat model. There was a significant lowering in the severity of disease symptoms and colonto-body weight ratio. The histopathological studies also confirmed successful treatment with microparticle formulation.

Hyperbranched Polyelectrolyte Copolymers as Novel Candidate Delivery Systems for Bio-Relevant Compounds

“…Weak polyelectrolytes partially dissociate when dissolved in an aqueous medium and, as a consequence their total charge, changes as a function of pH. This property enables complexation with oppositely charged components, while in certain circumstances, the ability of targeted drug release is demonstrated [ 24 , 25 , 26 , 27 ].…”