Assessment of Tailor-Made HPMC-Based Matrix Minitablets Comprising a Weakly Basic Drug Compound

Microenvironmental pH Control and Mixed Polymer Approaches to Optimise Drug Delivery with Hydrophilic Matrix Tablets

“…Others have indicated that it is necessary to optimise the acidifier level and choice [44], with again the lower pK a , lower solubility fumaric acid seeming to have advantages in improving the extended delivery of dipyridamole over the more soluble, but less acidic succinic acid. The slower release of fumaric acid from the hydrophilic matrix relative to succinic acid, associated with its lower solubility in the buffer, meant it could sustain the low microenvironmental pH for a longer period against the challenge of ingressing pH 6.8 buffer [44].…”

“…The slower release of fumaric acid from the hydrophilic matrix relative to succinic acid, associated with its lower solubility in the buffer, meant it could sustain the low microenvironmental pH for a longer period against the challenge of ingressing pH 6.8 buffer [44].…”

Dissolution-modulating mechanism of pH modifiers in solid dispersion containing weakly acidic or basic drugs with poor water solubility

“…The pH M can be modulated for drug dissolution as long as the pH modifier is present inside the solid dosage form [17,35,36]. Thus, evaluation of pH modifier release behaviors is crucial for thoroughly understanding the drug release mechanism from such pHmodulating systems.…”

High-amylose carboxymethyl starch matrices for oral sustained drug-release: In vitro and in vivo evaluation

“…Examples of these excipients are organic acids such as adipic, fumaric, tartaric and succinic acid, which can be used to increase the solubility of weak bases by decreasing the pH of the microenvironment (Gabr 1992;Siepe, Lueckel et al 2008), and basic excipients such as dicalcium phosphate (DCP), magnesium oxide (MgO) and magnesium hydroxide (Mg(OH) 2 ), used to increase the solubility of weak acids by increasing the pH of the microenvironment (Doherty and York 1989).…”