Pharmaceutical systems containing a mixture of drug, excipients, and polymer can be used as effective controlled release formulations. The presence of drug and excipients in the polymer matrix creates a complex mechanism that undergoes swelling, diffusion and erosion. DDDPlus™, an in vitro dissolution simulation software program (Simulations Plus, Inc.) was used to simulate the release of Adinazolam Mesylate from an HPMC K4M matrix. Different concentrations of HPMC-Lactose (filler) ratios were used to characterize the swelling and release behavior. The HPMC grade K4M (MWt 95000) was used to characterize the polymer chain disentanglement concentration (Cp) which influenced the polymer erosion. The active drug concentration was held constant at 3% (w/w) and HPMC-Lactose ratio %(w/w) was varied as 80:17, 65:32, 50:47, 35:62 and 20:77. DDDPlus™ simulations for these formulations accurately matched the in-vitro data.
By Anand Prabhakaran, John DiBella, Walter S. Woltosz, Michael B. Bolger