Published online Sep 14, 2013. doi: 10.3748/wjg.v19.i34.5665
Revised: May 9, 2013
Accepted: May 18, 2013
Published online: September 14, 2013
AIM: To compare the mucosal concentrations of 5-aminosalicylic acid (5-ASA) resulting from different pharmaceutical formulations and analyse the influence of inflammation on the mucosal concentrations.
METHODS: The study included 130 inflammatory bowel disease (IBD) patients receiving 5-ASA as pH-dependent-release formulations (73 patients), time-dependent-release formulations (11 patients), or pro-drugs (18 patients). In addition, 28 patients were receiving topical treatment (2-4 g/d) with pH-dependent-release formulations. Endoscopic biopsies were obtained from the sigmoid region during the colonoscopy. The 5-ASA concentrations (ng/mg) were measured in tissue homogenates using high-pressure liquid chromatography with electrochemical detection. The t test and Mann-Whitney test, when appropriate, were used for statistical analysis.
RESULTS: Patients receiving pH-dependent-release formulations showed significantly higher mucosal concentrations of 5-ASA (51.75 ± 5.72 ng/mg) compared with patients receiving pro-drugs (33.35 ± 5.78 ng/mg, P = 0.01) or time-dependent-release formulations (38.24 ± 5.53 ng/mg, P = 0.04). Patients with endoscopic remission had significantly higher mucosal concentrations of 5-ASA than patients with active disease (60.14 ± 7.95 ng/mg vs 35.66 ± 5.68 ng/mg, P = 0.02). Similar results were obtained when we compared patients with the histological appearance of remission and patients with active histological inflammation (67.53 ± 9.22 ng/mg vs 35.53 ± 5.63 ng/mg, P < 0.001). Significantly higher mucosal concentrations of 5-ASA were detected in patients treated with both oral and topical treatments in combination compared with patients who received oral treatment with pH-dependent-release formulations alone (72.33 ± 11.23 ng/mg vs 51.75 ± 5.72 ng/mg, P = 0.03).
CONCLUSION: IBD patients showed significant variability in mucosal 5-ASA concentrations depending on the type of formulation, and the highest mean concentration was achieved using pH-dependent-release formulations.
Core tip: We report on the concentrations of 5-aminosalicylic acid in the colonic mucosa of ulcerative colitis patients. Significant variations in concentration were observed that were dependent on the type of pharmaceutical formulation and the presence of active disease. Combined oral and topical therapy yielded higher tissue mesalamine concentrations. These differences should be taken into account in treatment strategies, especially in view of the fact that mesalamine can induce mucosal healing in ulcerative colitis.