Effects of the permeability characteristics of different polymethacrylates on the pharmaceutical characteristics of verapamil hyhdrochloride-loaded microspheres

Abstract

Microspheres containing verapamil hydrochloride (VRP) were prepared with various polymethacrylates, with different permeability characteristics (Eudragit RS 100, Eudragit RL 100, Eudragit L 100 and Eudragit L 100-55) and also with mixtures of these polymers in a 1:1 ratio using the solvent evaporation method. The aim was to investigate the effects of the permeability of the polymers on drug release rates and the characteristics of the microspheres. To achieve these aims, yield, incorporation efficiency, particle size and the distribution of microspheres were determined, and the influence of the inner phase viscosities prepared with different polymer and polymer mixtures on particle size and the distribution of microspheres were evaluated. Surface morphologies of microspheres were observed by scanning electron microscope. Drug release rates from microspheres were determined by the half-change method using a flow-through cell. The results indicate that microspheres with different surface morphologies and statistically different yields and incorporation efficiencies could be prepared and their particle size and distribution xariances resulted from the viscosity of the inner phase. Dissolution profiles showed that the drug release rate could be modified depending on the permeability characteristics of polymethacrylates.

Interpolymer combinations of chemically complementary grades of Eudragit copolymers: a new direction in the design of peroral solid dosage forms of drug delivery systems with controlled release (review)

“…The same method but in acetone:MeOH solutions was proposed for preparing verapamil-containing microspheres consisting of combinations of Eudragit ® RS100 with L100 or L100-55 in a 1:1 mass ratio [26]. Interesting trends were found by analyzing the viscosities of the disperse media and determining the particle sizes of the combined disperse phases.…”

Structural Transformations During Swelling of Polycomplex Matrices Based on Countercharged (meth)acrylate Copolymers (EudragitR EPO/EudragitR L 100-55)

“…Moreover, solid dispersions (coprecipitates) of different drugs and countercharged poly(meth)acrylates are successfully used in matrix tablets production {RLPO(RSPO)/S100[L100, Eudragit R L 100-55 (L100-55)]}, 8 (E100/S100). 9,10 Microspheres prepared by a solvent evaporation method with the copolymer combinations (RL100/L100-55), 11 [RS100/L100(L100-55)] 12 showed a stronger sustained release.…”

Preparation and physicochemical characterization of Eudragit® RL100 Nanosuspension with potential for Ocular Delivery of Sulfacetamide

“…Pignatello et al (34) showed that the drug release from Eudragit RL100 particles was complex in nature which involves the occurrence of dissolutive and diffusive phenomena. Overall the drug release rate was faster which were probably due to the high water permeability and swellability characteristics of Eudragit RL 100 (51). The presence of a high content of quaternary ammonium groups makes the polymer more permeable to water.…”