Diltiazem Hydrochloride Trapping in Poly(methacrylic Acid-Co-Acrylamide) Microparticles: In-Vitro Drug Delivery Studies

Microparticles based on poly(methacrylic acid-co-acrylamide) crosslinked with N,N’-methylene bisacrylamide were prepared by free radical polymerization using varying amounts of acrylamide (AAm), methacrylic acid (MAA), and N,N’-methylene bisacrylamide (NNMBA). The microparticles were loaded with antihypertensive drug, diltiazem hydrochloride (water-soluble), to investigate their release characteristics. The release behavior in pH 2.0 was much slower than in buffer solution at pH 7.4. The diffusion coefficients ranged from 08.03 × 10−6 to 25.40 × 10−6 cm2 min−1 in pH 2.0 buffer and from 02.41 × 10−4 to 35.25 × 10−4 cm2 min−1 in pH 7.4 buffer.