Mesalazine release from coated tablets: effect of dietary fibre

Effects of medicines used to treat gastrointestinal diseases on the pharmacokinetics of coadministered drugs: a PEARRL Review

Objectives

Drugs used to treat gastrointestinal diseases (GI drugs) are widely used either as prescription or over-the-counter (OTC) medications and belong to both the 10 most prescribed and 10 most sold OTC medications worldwide. The objective of this review article is to discuss the most frequent interactions between GI and other drugs, including identification of the mechanisms behind these interactions, where possible.

Key findings

Current clinical practice shows that in many cases, these drugs are administered concomitantly with other drug products. Due to their metabolic properties and mechanisms of action, the drugs used to treat gastrointestinal diseases can change the pharmacokinetics of some coadministered drugs. In certain cases, these interactions can lead to failure of treatment or to the occurrence of serious adverse events. The mechanism of interaction depends highly on drug properties and differs among therapeutic categories. Understanding these interactions is essential to providing recommendations for optimal drug therapy.

Summary

Interactions with GI drugs are numerous and can be highly significant clinically in some cases. While alterations in bioavailability due to changes in solubility, dissolution rate, GI transit and metabolic interactions can be (for the most part) easily identified, interactions that are mediated through other mechanisms, such as permeability or microbiota, are less well-understood. Future work should focus on characterising these aspects.

Possible interactions between dietary fibres and 5-aminosalicylic acid [corrected]

BACKGROUND

Potentially, a binding of 5-aminosalicylic acid (5-ASA) to dietary fibres could reduce the systemic absorption and increase the intraluminal amount [corrected]. The purposes of the study were to investigate if: (1) dietary fibres can bind 5-ASA in vitro, and (2) consumption of dietary fibres is related to disease activity in patients with ulcerative colitis (UC) treated with 5-ASA.

METHODS

In vitro: 15 g of Ispaghula Husk, wheat bran, citrus-pectin, or wheat flour were incubated in a 37°C buffered solutions of 5-ASA (1 g/l) for 3 hours at pH 6 and 7. The concentrations of 5-ASA were determined before and after the incubation using HPLC. In vivo: patients with UC were interviewed two to three times during 6 months. The fibre consumption was estimated and related to the disease activity (CAI, CRP, Faecal-calprotectin) and quality of life (IBDQ).

RESULTS

In vitro: 5-ASA was bound to Ispaghula Husk (5.3-10.0 mg/g) and wheat bran (4.6-5.5 mg/g), and to a minor degree to citrus-pectin. No differences were found in relation to pH. In vivo: 29 patients completed the scheduled interviews. No significant changes in fibre consumption were observed over time; however, patients consuming a diet high in fibre (>20 g/day) had significantly lower CRP (p <0.01) and faecal-calprotectin (p <0.01) than those consuming less fibre (<20 g/dg).

CONCLUSIONS

Patients with a high intake of fibre had a lower disease activity than those with low intake. Ispaghula Husk bound 5-ASA in vitro, independent of pH. The effect might be clinically relevant in patients with UC treated with 5-ASA.

Balsalazide is superior to mesalamine in the time to improvement of signs and symptoms of acute mild-to-moderate ulcerative colitis

OBJECTIVE

Balsalazide is a novel azo-bonded 5-aminosalicylic acid treatment for mild-to-moderate ulcerative colitis. The study objective was to compare symptomatic remission rates with balsalazide and mesalamine while controlling for extent of disease and time since diagnosis in patients with active, mild-to-moderate ulcerative colitis.

METHODS

A total of 173 patients with sigmoidoscopically verified ulcerative colitis were randomized to 8 wk of double-blind treatment with balsalazide 6.75 g/day or mesalamine 2.4 g/day. Both treatments provided 2.4 g/day of oral 5-aminosalicylic acid. Patients maintained symptom diaries throughout the treatment period.

RESULTS

Overall, 46% of balsalazide- and 44% of mesalamine-treated patients achieved symptomatic remission. Higher response rates were noted in newly diagnosed patients with < or = 40 cm of disease (68% vs 61%) than in recently relapsed patients with >40 cm of disease (36% vs 25%). The median time to symptomatic remission was 12 days shorter with balsalazide (25 days) than with mesalamine (37 days). Significantly more balsalazide patients showed sigmoidoscopic (p = 0.002), stool frequency (p = 0.006), rectal bleeding (p = 0.006), and physician's global assessment score (p = 0.013) improvement by 14 days than did mesalamine patients. Similar proportions of patients reported adverse events (54% vs 64%), which were most commonly related to the gastrointestinal and central and peripheral nervous systems.

CONCLUSIONS

Balsalazide is an effective and safe treatment for mild-to-moderate ulcerative colitis. Improvement of symptoms occurs considerably earlier with balsalazide than with mesalamine.

Mono- and biphasic plasma concentration-time curves of mesalazine from a 500 mg suppository in healthy male volunteers controlled by the time of defecation before dosing

This study was based on data from a bioequivalence study (n=24) of two different formulations of suppositories containing 500 mg mesalazine (formulation I and II), with a similar dissolution profile in phosphate buffer pH 6.8. There was a large intra- and intersubject variability in the plasma concentration-time curves of mesalazine from both suppositories. The aim of the investigation was to identify the parameters that caused the observed large variations in release and absorption of mesalazine in the rectum. Plasma mesalazine and acetylmesalazine, and urine acetylmesalazine concentrations were determined according to validated methods involving HPLC analysis with coulometric detection. Lower limit of quantitation values were respectively 10.4 and 19.4 ng mL(-1) in plasma and 0.96 microg mL(-1) in urine. The time of defecation before and after insertion was recorded. There was a clear distinction between subjects who showed monophasic mesalazine release/absorption and those who showed biphasic and more extended release/absorption. With formulation I there was a correlation between time of defecation before dosing and the type of absorption, monophasic and biphasic absorbers showed a significant difference in the time of defecation, e.g. 9.7+/-5.6 h vs 18.8+/-11.9 h (P = 0.0218). The impact of time of defecation before dosing was non-significant with formulation II, 16.7+/-7.2 h vs 15.1+/-4.2 h (P = 0.67). The impact of the time elapsed between administration and time of defecation after the insertion of the suppository was not significant for the type of release/absorption. The plasma concentration-time curves of the metabolite ran parallel to that of the parent drug, the more parent drug was released/absorbed, the more was acetylated (P = 0.0013) and excreted into the urine (P = 0.0004). After absorption the compound was metabolized into acetylmesalazine, and renally excreted (12-13% of the dose). Monophasic release/ absorption resulted in 7.1% metabolite with I and 10.3% with II (P = 0.0004), while biphasic release/absorption gave 16.8% metabolite with I and 15.5% with II. The renal clearance of the metabolite acetylmesalazine was independent of the observed defecation patterns (300 mL min(-1), P > 0.8), stool composition, and type of absorption.

Dose loading with delayed-release mesalazine: a study of tissue drug concentrations and standard pharmacokinetic parameters

AIMS

Tissue concentrations of 5-aminosalicylic acid (5ASA) and its metabolites may influence the clinical course of inflammatory bowel disease. Since the factors that determine tissue drug concentrations are unknown we have studied the relationships between the oral dose of delayed-release mesalazine, rectal tissue drug concentrations and standard pharmacokinetic parameters.

METHODS

Twelve healthy volunteers were studied following 7 days treatment with 1.2, 2.4 and 4.8 g of delayed-release mesalazine daily. 5-aminosalicylic acid and N-acetyl 5-aminosalicylic acid concentrations were measured in serum, urine, stool and rectal tissue biopsies.

RESULTS

Serum concentrations and 24 h urinary excretion of 5ASA and N-acetyl 5ASA increased as the oral dose of mesalazine was increased from 1.2 g through 2.4 g to 4.8 g daily (serum area under curve (AUC):5ASA = 3. 9, 15.4 and 46.8 microg ml-1 h, P < 0.0001; N-acetyl 5ASA = 17.2, 30. 9 and 57.8 microg ml-1 h, P < 0.0001: urinary excretion: 5ASA = 1.8, 85.5 and 445 mg, P < 0.0001; N-acetyl 5ASA = 250, 524 and 1468 mg, P < 0.0001, respectively). Faecal 5ASA excretion increased as the oral dose increased from 1.2 g to 2.4 g but did not increase further with 4.8 g daily dosing whereas faecal N-acetyl 5ASA excretion was similar at all three doses. Rectal tissue concentrations of 5ASA increased markedly, and N-acetyl 5ASA increased modestly, as the dose of oral mesalazine increased from 1.2 g to 2.4 g daily but neither increased further with 4.8 g daily dosing.

CONCLUSIONS

The relationship between the ingested dose of delayed-release mesalazine and rectal tissue drug concentrations is complex. Factors other than dose are likely to be important determinants of rectal tissue drug concentrations.

Oral delayed-release mesalazine: a review of its use in ulcerative colitis and Crohn's disease

Oral delayed-release mesalazine is an enteric-coated formulation which releases mesalazine in the terminal ileum and colon. Up to 74% of patients with mild to moderately active ulcerative colitis experience endoscopic or symptomatic improvement (including remission) or both when treated with oral delayed-release mesalazine 2.4 to 4.8 g/day. There is a trend towards a better response in patients receiving higher daily dosages of oral delayed-release mesalazine, especially in patients with active distal disease. In patients with left-sided ulcerative colitis, oral balsalazide 6.75 g/day appears to be more effective than oral delayed-release mesalazine 2.4 g/day, but a higher dosage of oral delayed-release mesalazine 4.8 g/day may provide additional benefit in these patients. Oral delayed-release mesalazine 0.8 to 4.4 g/day appears to be as effective as sulfasalazine 2 to 4 g/day, prolonged-release mesalazine 1.5 g/day or balsalazide 3 g/day in maintaining remission in patients with ulcerative colitis. The optimal dosage of oral delayed-release mesalazine for the maintenance of remission is unclear. However, oral delayed-release mesalazine 1.6 g/day with rectal mesalazine 4g, administered twice weekly, was more effective than oral drug alone in maintaining remission in patients at high risk of relapse. In patients with left-sided or distal disease oral olsalazine 1 g/day appeared to be superior to oral delayed-release mesalazine 1.2 g/day for maintenance of symptomatic remission. Limited data in patients with Crohn's disease have shown oral delayed-release mesalazine 0.4 to 4.8 g/day to be an effective therapy for active disease (remission in up to 45% of patients) and for quiescent disease (relapse in 34% of recipients over a duration of up to 12 months). Preliminary data indicate that oral delayed-release mesalazine 2.4 g/day is effective in preventing postoperative recurrence of Crohn's disease. Oral delayed-release mesalazine is effective and well tolerated in sulfasalazine-intolerant patients with ulcerative colitis or Crohn's disease.

CONCLUSIONS

Oral delayed-release mesalazine is effective in patients with mild to moderately active or quiescent ulcerative colitis. Available data suggest that patients with left-sided or distal ulcerative colitis are likely to require higher daily dosages of oral delayed-release mesalazine or supplementation with rectal mesalazine. Oral delayed-release mesalazine also appears to be effective in active and quiescent Crohn's disease. The drug is well tolerated and it appears to be effective in sulfasalazine-intolerant patients.

[Pharmacokinetic data for different 5-aminosalicylic acid and budesonide preparations]

Different orally and rectally applicable forms of 5-ASA and budesonide have been developed to achieve sufficient high concentrations of the active moieties at the site of inflammation (small and/or large bowel) and to limit the systemic action of the drugs. This concept of drug targeting could be accomplished by both special galenic formulations and by utilizing the pharmacokinetic properties of the agents especially their high intestinal and hepatic presystemic elimination. Thus, 5-ASA and budesonide represent drugs of first choice in the treatment of Crohn's disease and ulcerative colitis. This review describes the various pharmacokinetic and (patho)physiologic factors and their impact on drug delivery and biological availability of the different 5-ASA and budesonide preparations.