According to the South African Gastroenterology Society, oral and topical 5-aminosalicylic acid (5-ASA) are considered first-line therapy for mild to moderately active UC. The choice of oral or topical therapy, or the use of both in combination, depends on the extent and activity of the disease.

Multi-matrix (MMX) mesalazine is an oral, high-strength (1.2g/tablet), once-daily formulation of 5-ASA that incorporates a Eudragit-based, gastro-resistant, pH-dependent acrylic-based enteric coating, combined with a hydrogel-forming MMX core. The enteric coating is designed to delay the release of 5-ASA during transit through the upper GI tract, while hydrophilic and lipophilic excipients within the MMX tablet core are designed to prolong release of 5-ASA throughout the colon after the coating has dissolved. It is indicated for use in patients with mild to moderate UC.

Brunner et al (2003) stated, “Mesalazine 5-ASA-containing formulations represent a cornerstone in the treatment of inflammatory bowel diseases.” In a first study, gastrointestinal transit was followed by gamma scintigraphy after single-dose application of tablets containing 1200mg mesalazine to 12 healthy male volunteers. Tablet erosion started after 6.9 +- 1.1 hour in the ascending or transverse colon. Radioactivity spread homogeneously throughout the colon, indicating the sustained release of active 5-ASA. According to Tenjarla et al (2007), 5-ASA mesalazine is the current first-line treatment for mild to moderate UC, which most commonly affects the distal part of the colon. MMX mesalazine was created to be a novel, once-daily 5-ASA formulation. MMX mesalazine in tablet form has a pH-dependent, gastro-resistant coating and is designed to delay the release of 5-ASA during transit through the  upper gastrointestinal tract. It consists of hydrophilic and lipophilic excipients that are designed to prolong the release of 5-ASA throughout the colon.

The oral 5-ASA tablet uses a pH-dependent enteric coating to delay initial release of the active drug until it reaches the terminal ileum. This formulation has proved effective for the induction of remission in patients with active mild to moderate UC in two pivotal phase 3 clinical studies. Gamma scintigraphy imaging following oral ingestion of single tablets showed that radioactivity spread homogeneously along the entire length of the colon.

This coating delays release of 5-ASA until the pH is 7.0 or higher (which is usually encountered in the terminal ileum). As the gastro-resistant coating disintegrates, it is thought that intestinal fluids interact with hydrophilic excipients, causing the tablet to swell (like a sponge exposed to water) and form an outer viscous gel mass that is believed to slow diffusion of 5-ASA from the tablet core into the colonic lumen. As the tablet and its surrounding gel mass progress through the colon, it is thought that pieces of the gel mass gradually break away from the core, releasing 5-ASA.

It is supposed that the lipophilic excipient slows the penetration of aqueous fluids into the tablet core, reducing the rate of dissolution and prolonging therapeutic activity.

CONCLUSION

“MMX mesalazine appears to be a valuable option in the management of patients with mild to moderate ulcerative colitis,” (Yang et al 2011).