A novel dual-prodrug carried by cyclodextrin inclusion complex for the targeting treatment of colon cancer.

BACKGROUND: There is an obvious correlation between ulcerative colitis and colorectal cancer, and the risk of colorectal cancer in patients with ulcerative colitis is increasing. Therefore, the combination therapy of anti-inflammatory and anti-tumor drugs may show promising to inhibit colon cancer. 5-aminosalicylic acid (5-ASA) with anti-inflammatory function is effective for maintaining remission in patients with ulcerative colitis and may also reduce colorectal cancer risk. Histone deacetylase (HDAC) plays an essential role in the progression of colon cancer. Butyric acid (BA) is a kind of HDAC inhibitor and thus shows tumor suppression to colon cancer. However, the volatile and corrosive nature of BA presents challenges in practical application. In addition, its clinical application is limited due to its non-targeting ability and low bioavailability. We aimed to synthesize a novel dual-prodrug of 5-ASA and BA, referred as BBA, to synergistically inhibit colon cancer. Further, based on the fact that folate receptor (FR) is over-expressed in most solid tumors and it has been identified to be a cancer stem cell surface marker in colon cancer, we took folate as the targeting ligand and used carboxymethyl-ß-cyclodextrin (CM-ß-CD) to carry BBA and thus prepared a novel inclusion complex of BBA/FA-PEG-CM-ß-CD. RESULTS: It was found that BBA/FA-PEG-CM-ß-CD showed significant inhibition in cell proliferation against colon cancer cells SW620. It showed a pro-longed in vivo circulation and mainly accumulated in tumor tissue. More importantly, BBA/FA-PEG-CM-ß-CD gave great tumor suppression effect against nude mice bearing SW620 xenografts. CONCLUSIONS: Therefore, BBA/FA-PEG-CM-ß-CD may have clinical potential in colon cancer therapy.

Mesalazine and inflammatory bowel disease - From well-established therapies to progress beyond the state of the art.

Inflammatory bowel disease incidence has been constantly rising for the past few decades. Current therapies attempt to mitigate its symptoms since no cure is established. The most commonly prescribed drug for these patients is 5-aminosalicylic acid (5-ASA). Due to the low rate and seriousness of side effects compared to other therapies, 5-ASA is still largely prescribed in many stages of inflammatory bowel disease, including scenarios where evidence suggests low effectiveness. Although commercialized formulations have come a long way in improving pharmacokinetics, it is still necessary to design and develop novel delivery systems capable of increasing effectiveness at different stages of the disease. In particular, micro- and nano-sized particles might be the key to its success in Crohn's disease and in more serious disease stages. This review provides an overview on the clinical significance of 5-ASA formulations, its limitations, challenges, and the most recent micro- and nanoparticle delivery systems being designed for its controlled release. Emergent alternatives for 5-ASA are also discussed, as well as the future prospects for its application in inflammatory bowel disease therapies.

Research on Preparation of 5-ASA Colon-Specific Hydrogel Delivery System without Crosslinking Agent by Mechanochemical Method.

PURPOSE: This study aims to overcome the challenges of the current oral targeted drug delivery system, such as the complex preparation process, poor biocompatibility, and delayed drug release. METHODS: Here, a non-covalent polymer hydrogel was prepared using the mechanochemical method, and the solid phase loading of 5-amino salicylic acid (5-ASA) was realized. RESULTS: The results obtained from the thermodynamics study, particle size analysis, and electron microscopy show that chitosan (CS) and sodium alginate (SA) form a pH-sensitive hydrogel under the mechanochemical force and also maintain good stability in aqueous solution. Fluorescent tracers study showed that the pH-sensitive hydrogel could achieve the targeted drug release in the colon and the retention time was over 12 h. Next, in vivo efficacy studies, change in mice body weight, DAI (disease activity index) score, thymus, and spleen index, and the diseased state of the mice colon revealed that the pH-sensitive hydrogel is an improved drug delivery system over 5-ASA API commercial preparations as observed in the efficacy and toxicological studies. CONCLUSION: This method uses an innovative preparation technology that without the need of cross-linking agent to produce an efficient colon-targeted drug delivery system for the treatment of ulcerative colitis.

A chromatographic approach to development of 5-aminosalicylate/folic acid fixed-dose combinations for treatment of Crohn's disease and ulcerative colitis.

Medication adherence is an important factor in inflammatory bowel disease therapy, which includes regular supplementation of malabsorbed vitamins. Absorption of folic acid is limited due to the damaging of the gastrointestinal tract, which can increase the chances to develop megaloblastic anaemia and colorectal cancer. In this work, 5-aminosalicylates (mesalazine, balsalazide, sulfasalazine and olsalazine) and folic acid were characterized regarding their pharmacokinetic related properties (hydrophobicity, phospholipid and plasma protein binding) using the biomimetic chromatographic approach. Despite the high binding percentage of 5-aminosalicylates for human serum albumin (> 61.44%), results have shown that folic acid binding to human serum albumin protein is far greater (69.40%) compared to α1-acid-glycoprotein (3.45%). Frontal analysis and zonal elution studies were conducted to provide an insight into the binding of folic acid to human serum albumin and potential competition with 5-aminosalicylates. The analytical method for the simultaneous determination of assay in proposed fixed-dose combinations was developed and validated according to ICH Q2 (R1) and FDA method validation guidelines. Separation of all compounds was achieved within 16 min with satisfactory resolution (Rs > 3.67) using the XBridge Phenyl column (150 × 4.6 mm, 3.5 µm). High linearity (r > 0.9997) and precision (RSD < 2.29%) was obtained, whilst all recoveries were within the regulatory defined range by British (100.0 ± 5.0%) and United States Pharmacopeia (100.0 ± 10.0%).

Solving the questions regarding 5-aminosalitylate formulation in the treatment of ulcerative colitis.

5-aminosalicylate is a fundamental treatment for patients with ulcerative colitis with mild-to-moderate disease; however, evidence for 5-aminosalicylate treatment is unclear in some situations. This review discusses the clinical guidelines and previous studies, and highlights the following points: (1) Although rectal 5-aminosalicylate is effective for proctitis, physicians should endeavor to reduce patient's distress when administering suppositories or enema as the first-line therapy. It should be clarified whether oral 5-aminosalicylate alone with a drug delivery system that allows higher 5-aminosalicylate concentrations to reach the distal colon would be as effective as rectal 5-aminosalicylate therapy. (2) There has been no direct evidence demonstrating the clinical efficacy of switching the 5-aminosalicylate treatment to other 5-aminosalicylate formulations. However, switching to a different 5-aminosalicylate formulation may be indicated if clinical symptoms are not progressive. (3) Several studies have shown that colonic mucosal 5-aminosalicylate concentration correlates with clinical and endoscopic severity; however, it is unclear whether a high 5-aminosalicylate concentration has therapeutic efficacy. (4) The maximum dose of 5-aminosalicylate is necessary for patients with risk factors for recurrence or hospitalization. (5) Optimization of 5-aminosalicylate dosage may be indicated even for quiescent patients with ulcerative colitis if mucosal healing is not obtained, and if patients have multiple risk factors for recurrence. (6) Furthermore, the discontinuation of 5-aminosalicylate is acceptable when biologics are used. Because there are many "old studies" providing evidence for 5-aminosalicylate formulations, more clinical studies are needed to establish new evidence.

Does the 5-Aminosalicylate Concentration Correlate with the Efficacy of Oral 5-Aminosalicylate and Predict Response in Patients with Inflammatory Bowel Disease? A Systematic Review.

BACKGROUND: Oral 5-aminosalicylic acid (5-ASA, mesalazine) is the first choice therapeutic agent for treating mild-to-moderate ulcerative colitis (UC). Unfortunately a significant group of patients fail to respond. Therapeutic drug monitoring might help to maintain or induce remission by providing a tool for optimization of 5-ASA therapy. However, plasma and urine concentrations of 5-ASA reflect systemic uptake and are not useful to evaluate therapeutic effect. OBJECTIVES: To explore if mucosal and faecal 5-ASA values correlate with disease activity and/or therapeutic effects in patients with inflammatory bowel disease, especially UC. METHOD: We identified studies that analysed 5-ASA in faeces or mucosa of humans using an oral 5-ASA formulation, using PubMed and Embase. RESULTS: In total, 39 studies (n = 939) were included, 27 on faecal 5-ASA, 9 on mucosal concentrations, and 3 on both faecal and mucosal values. We included 33 cross-sectional studies, 3 randomised clinical trials, 2 longitudinal cohorts and 1 randomized cross-over study. Mucosal 5-ASA concentrations in healthy subjects and patients on equivalent doses of 5-ASA were not found to differ remarkably. In the sub-analysis of mucosal 5-ASA concentrations in patients with active or quiescent UC, a higher concentration was seen during remission. Faecal concentrations were associated with 5-ASA doses but not with disease activity. Differences in faecal or mucosal 5-ASA values could not be ascribed to different 5-ASA formulations. CONCLUSIONS: An increase of the mucosal 5-ASA concentrations was observed during remission in patients with UC. No clear relationship between the faecal 5-ASA excretion and the therapeutic efficacy was identified.

Effects of Differential Food Patterns on the Pharmacokinetics of Enteric-Coated Mesalazine Tablets in the Same Cohort of Healthy Chinese Volunteers.

This study aimed to simultaneously determine mesalazine (5-ASA) and its major metabolite N-Ac-5-ASA in the plasma and to evaluate the impact of different food patterns on the relative bioavailability and pharmacokinetics of a single oral dose of 5-ASA in healthy subjects. In this single-dose, open-label, 3-period, 3-treatment crossover study, the subjects received a single, oral dose of 500-mg enteric-coated mesalazine tablet together with either a low-fat or a high-fat breakfast or under fasting condition (reference). The pharmacokinetic parameters were determined by noncompartmental methods and analyzed with a linear mixed-effect model. The geometric least squares mean ratio for the area under the plasma concentration-time curve from zero to infinity of N-Ac-5-ASA was 1.05 (90% confidence interval [CI], 0.70-1.58) for high-fat/fasted condition and 1.06 (90%CI, 0.82-1.36) for low-fat/fasted condition. The least squares mean ratio of 5-ASA was 0.86 (90%CI, 0.65-1.14) for high-fat/fasted condition and 0.78 (90%CI, 0.60-1.02) for low-fat/fasted condition. All P values were >.05. The mean maximum plasma concentration and the time to reach the maximum plasma concentration of N-Ac-5-ASA were 2084 ng/mL, 8 hours; 2639 ng/mL, 11 hours, and 2409 ng/mL, 9 hours for fasted, high-fat, and low-fat, respectively. The values of 5-ASA were 1950 ng/mL, 7 hours; 2869 ng/mL, 9 hours; and 2837 ng/mL, 8 hours for fasted, high-fat, and low-fat condition. 5-ASA was well tolerated under all 3 conditions. Food delayed the absorption of 5-ASA, especially a high-fat meal. Therefore, enteric-coated mesalazine tablets should be taken before meals to avoid causing patients slow response and any effect of food on its efficacy.

A Phase I Trial of Berberine in Chinese with Ulcerative Colitis.

The Chinese natural product, berberine, has biological properties that support its potential efficacy as a colon cancer prevention agent. Its longstanding use in China to treat gastrointestinal tract and rheumatologic disorders is generally regarded as safe, supporting initial investigations in an at-risk population, such as individuals with ulcerative colitis. However, the safety of berberine in this population is not established. Individuals living in China with biopsy-proven ulcerative colitis, ≤grade 2 dysplasia, and with a ulcerative colitis disease activity index (UCDAI) score ≤1 on mesalamine, were randomized 3:1 in a double-blind phase I trial to berberine 900 mg/day or placebo for 3 months, with the primary objective of assessing safety. Blood samples and biopsies of the colorectum, from prespecified locations, were collected prior to and following therapy. Secondary endpoints included changes in UCDAI score, and in tissue and plasma markers of inflammation. Of toxicities at least possibly related, one episode of grade 3 elevation in transaminases and one episode of grade 1 nausea were observed among 12 individuals on berberine, and none were observed among 4 on placebo. The mean plasma berberine concentration was 3.5 nmol/L after berberine treatment, significantly higher than 0.5 nmol/L with placebo. Berberine significantly decreased the Geboes grade in colonic tissue, but had a nonsignificant effect on other tissue or blood biomarkers related to cell growth and inflammation. The combination of berberine and mesalamine is well tolerated in Chinese with ulcerative colitis and may enhance mesalamine's anti-inflammatory effects in colonic tissue.

In vitro and human pharmacoscintigraphic evaluation of an oral 5-ASA delivery system for colonic release.

5-aminosalicylic acid (5-ASA) is the most widely used drug for the treatment of ulcerative colitis. The benefits of targeted delivery of 5-ASA to the large intestine are well known, resulting in reduced systemic absorption and increased local concentrations at the disease site. In the present study, a 5-ASA colon delivery system based on the time-dependent strategy, exploiting the relatively consistent small intestinal transit time (SITT), was manufactured and evaluated in vitro as well as in vivo. The system was obtained by successive spray-coating of an immediate-release tablet core with low-viscosity HPMC and Eudragit® L. The enteric film was effective in preventing release during the acidic stage of the in vitro test, while the HPMC coating brought about reproducible lag phases prior to release in phosphate buffer medium. A γ-scintigraphy investigation pointed out that, following administration to fasted and fed volunteers, disintegration of the units never occurred prior to colon arrival. In all cases, a lag time preceded the appearance of the drug and its N-acetyl metabolite in the bloodstream, which was found to correlate with the time of disintegration in a linear mode. The plasma levels of the drug and metabolite as well as their cumulative urinary recovery were relatively low with respect to those reported when 5-ASA is delivered to the small bowel.

Spray dried formulation of mesalamine embedded with probiotic biomass for the treatment of ulcerative colitis: in-vitro and in-vivo studies.

This study is using the targeted approach and anti-inflammatory action of the probiotic biomass to lessen the side effects of therapeutic agents of ulcerative colitis. The aim of the present study is to prepare mesalamine loaded eudragit S-100 with probiotic microparticles by spray drying method. The in-vitro release of the optimized formulation was 90.55 ± 2.42 in 24 hr, which display controlled drug release of mesalamine at a particular region. Mesalamine loaded eudragit S-100 with probiotic microparticles (F12) presented average particle size of 4.91 µm. The statistical analysis was done by one way ANOVA and then comparison test of Bonferroni was done and p values <.05 were considered as significant. The effects of spray dried microparticles over inflamed Caco-2 cell were also evaluated by determining the concentration of IL-8. From in-vivo study it was seen that pretreatment of mesalamine with probiotic prevents DNBS (Dinitrobenzenesulfonic acid) induced colitis in rats and represents protective action against ulcerative colitis because of its antioxidant and anti-inflammatory actions. The results give the foundation for a combination of targeted approach along with the anti-inflammatory potential of the probiotic which might help to decrease the problems which are seen with the traditional cure and management of ulcerative colitis.

Mechanistic analysis and experimental verification of bicarbonate-controlled enteric coat dissolution: Potential in vivo implications.

Enteric coatings have shown in vivo dissolution rates that are poorly predicted by traditional in vitro tests, with the in vivo dissolution being considerably slower than in vitro. To provide a more mechanistic understanding of this, the dependence of the release properties of various enteric-coated (EC) products on bulk pH and bicarbonate molarity was investigated. It was found that, at presumably in vivo-relevant values, the bicarbonate molarity is a more significant determinant of the dissolution profile than the bulk pH. The findings also indicate that this steep relationship between the dissolution of enteric coatings and bicarbonate molarity limits those coatings' performance in vivo. This is attributed to the relatively low bicarbonate molarities in human intestinal fluids. Further, the hydration and dehydrations kinetics of carbonic acid and carbon dioxide are not sufficiently rapid to reach equilibrium in the diffusion layer surrounding a dissolving ionizable solid. This results in the effective pKa of bicarbonate in the diffusion layer being lower than that determined potentiometrically at equilibrium in the bulk surrounding fluid. These results demonstrate the importance of thoroughly investigating the intestinal bicarbonate concentrations and using bicarbonate buffers or properly designed surrogates (if possible) when evaluating enteric drug products during product development and quality control.

Mucosal 5-aminosalicylic acid concentration, drug formulation and mucosal microbiome in patients with quiescent ulcerative colitis.

BACKGROUND: 5-aminosalicylic acid (5-ASA) is the first-line therapy for ulcerative colitis (UC). 5-ASA acts locally in the colonic mucosa by numerous proposed mechanisms, and is metabolised by N-acetyltransferase (NAT). Large variations in mucosal 5-ASA concentrations have been reported, but the underlying mechanisms are not understood. AIM: To study the relationship between 5-ASA concentration, 5-ASA formulation, NAT genotype and bacterial microbiome in patients with UC. METHODS: Patients with quiescent UC, using monotherapy of Mezavant (n = 18), Asacol (n = 14) or Pentasa (n = 10), 4.0-4.8 g/day were included. 5-ASA was measured in colonic mucosal biopsies and serum by ultra-high performance liquid chromatography. NAT genotypes were determined by Sanger sequencing. Bacterial microbiome was sequenced from faeces and mucosa by 16S rRNA sequencing using Illumina Miseq. RESULTS: Mezavant provided the highest mucosal 5-ASA levels (geometric mean 2.39 ng/mg), followed by Asacol (1.60 ng/mg, 33% lower, P = 0.50) and Pentasa (0.57 ng/mg, 76% lower, P = 0.033). Mucosal 5-ASA concentration was not associated with NAT genotype, but serum 5-ASA concentration and NAT1 genotype was associated (P = 0.044). Mucosal 5-ASA concentration was positively associated with mucosal bacterial diversity (P = 0.0005) and bacterial composition. High mucosal 5-ASA concentration was related to reduced abundance of pathogenic bacteria such as Proteobacteria, and increased abundance of several favourable bacteria such as Faecalibacterium. CONCLUSIONS: Mucosal 5-ASA concentration is positively associated with bacterial diversity and a mucosal bacterial composition that are perceived favourable in UC. Mezavant yielded higher mucosal 5-ASA concentrations than Pentasa. 5-ASA may have beneficial effects on the mucosal microbiome, and high concentrations possibly amend dysbiosis in UC.

Xylan from Pineapple Stem Waste: a Potential Biopolymer for Colonic Targeting of Anti-inflammatory Agent Mesalamine.

We have successfully conjugated mesalamine (5-aminosalicylic acid, 5-ASA) with xylan, a biopolymer isolated from pineapple stem waste, to form xylan-5-ASA conjugate. The biopolymer was used to provide colon-targeting properties for 5-ASA, a golden standard anti-inflammatory agent commonly used for ulcerative colitis treatment. A series of data from FTIR spectroscopy, UV-Vis spectrophotometry, and HPLC confirmed the xylan-5-ASA conjugate formation. To ensure successful colon targeting properties, in vitro and in vivo drug release studies after oral administration of xylan-5-ASA conjugate to Wistar rats were performed. Xylan-5-ASA conjugate was able to retain 5-ASA release in the upper gastrointestinal tract fluid simulation but rapidly released 5-ASA in the rat colon fluid simulation. In vivo release profile shows a very low peak plasma concentration, reached at 6 h after xylan-5-ASA conjugate administration. The delayed release and the lower bioavailability of 5-ASA from xylan-5-ASA conjugate administration compared to free 5-ASA administration confirmed the successful local colon delivery of 5-ASA using xylan-5-ASA conjugate. The administration of xylan-5-ASA conjugate also exhibited greater efficacy in recovering 2,4,6-trinitrobenzene sulfonic acid-induced colon ulcer compared to free 5-ASA administration. Taken together, xylan isolated from pineapple stem waste is promising to obtain colon targeting property for 5-ASA.

pH-Dependent 5-Aminosalicylates Releasing Preparations Do Not Affect Thiopurine Metabolism.

BACKGROUND/AIMS: Thiopurines are key drugs in maintenance therapy for treating inflammatory bowel disease (IBD). Time-dependent 5-aminosalicylates (5-ASA) releasing preparations (time-dependent 5-ASA) increase 6-thioguanine nucleotide (6-TGN), an active metabolite of thiopurines. However, the effects of pH-dependent 5-ASA releasing preparations (pH-dependent 5-ASA) on thiopurine metabolism were not reported. METHODS: We conducted a retrospective study of 134 IBD patients who received thiopurine treatment. The 6-methylmercaptopurine (6-MMP)/6-TGN values after taking the same dose of thiopurine preparations for at least 28 days were included. RESULTS: There was a significant decrease in the 6-MMP/6-TGN ratio in time-dependent 5-ASA compared with group without 5-ASA preparations and the pH-dependent 5-ASA group (p = 0.008 and < 0.001 respectively). Spearman's rank correlation coefficient indicated a negative relationship between the daily oral dose of time-dependent 5-ASA and the 6-MMP/6-TGN ratio (r = -0.362, p = 0.003). Multivariate logistic regression analysis was performed in the groups with 6-MMP/6-TGN ratios of 1 or more and less than 1. The use of time-dependent 5-ASA and concomitant allopurinol negatively affected the independent 6-MMP/6-TGN ratio (p = 0.006 and 0.007 respectively). CONCLUSION: Our study revealed that time-dependent but not pH-dependent 5-ASA decreases the 6-MMP/6-TGN ratio. We also confirmed that concomitant allopurinol results in a low 6-MMP/6TGN ratio.

Clinical Pharmacokinetic and Pharmacodynamic Considerations in the Treatment of Ulcerative Colitis.

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) of unknown etiology, probably caused by a combination of genetic and environmental factors. The treatment of patients with active UC depends on the severity, localization and history of IBD medication. According to the classic step-up approach, treatment with 5-aminosalicylic acid compounds is the first step in the treatment of mild to moderately active UC. Corticosteroids, such as prednisolone are used in UC patients with moderate to severe disease activity, but only for remission induction therapy because of side effects associated with long-term use. Thiopurines are the next step in the treatment of active UC but monotherapy during induction therapy in UC patients is not preferred because of their slow onset. Therapeutic drug monitoring (TDM) of the pharmacologically active metabolites of thiopurines, 6-thioguanine nucleotide (6-TGN), has proven to be beneficial. Thiopurine S-methyltransferase (TMPT) plays a role in the metabolic conversion pathway of thiopurines and exhibits genetic polymorphism; however, the clinical benefit and relevance of TPMT genotyping is not well established. In patients with severely active UC refractory to corticosteroids, calcineurin inhibitors such as ciclosporin A (CsA) and tacrolimus are potential therapeutic options. These agents usually have a rather rapid onset of action. Monoclonal antibodies (anti-tumor necrosis factor [TNF] agents, vedolizumab) are the last pharmacotherapeutic option for UC patients before surgery becomes inevitable. Body weight, albumin status and antidrug antibodies contribute to the variability in the pharmacokinetics of anti-TNF agents. Additionally, the use of concomitant immunomodulators (thiopurines/methotrexate) lowers the rate of immunogenicity, and therefore the concomitant use of anti-TNF therapy with an immunomodulator may confer some advantage compared with monotherapy in certain patients. TDM of anti-TNF agents could be beneficial in patients with primary nonresponse and secondary loss of response. The potential benefit of applying TDM during vedolizumab treatment has yet to be determined.

Determination of Mesalamine levels in Human Milk as a Function of Dose.

BACKGROUND: Oral mesalamine (5-amino salicylic acid [5-ASA]) is an anti-inflammatory agent commonly used to treat inflammatory bowel disease such as ulcerative colitis and Crohn's disease. The transfer of mesalamine into human milk has to date been poorly described at the current dosages and newer formulations. This study was designed to determine transfer of mesalamine into human milk as a function of maternal dose and time, and dosage form. STUDY DESIGN: Ten breastfeeding mothers (age 28-41 years) suffering from inflammatory bowel disease were recruited who provided milk samples at 0, 1, 2, 4, 8, 12, and 24 hours after a single daily dose of oral mesalamine in pH-dependent gastroresistant coated tablets (1.2, 2.4, 3.6, and 4.8 g). Milk samples were analyzed using liquid chromatography/tandem mass spectrometry. RESULTS: A total of 10 women were enrolled for the study. The calibration curve for mesalamine was linear over a concentration range of 0.32-200 ng/mL. Irrespective of maternal dose, mesalamine levels in milk were exceedingly low. However, a wide range of mesalamine levels were observed among all the participants. The relative infant doses were all lower than 0.1% (range 0.003-0.085%). CONCLUSION: Regardless of dose and high variability, mesalamine levels in human milk were present in exceedingly low levels. The mothers in this study reported no side effects with their infants. These results suggest that the transfer of mesalamine into milk is very low and poses minimal risks to the breastfed infant.

Beta-Glucan based temperature responsive hydrogels for 5-ASA delivery.

A series of temperature responsive hydrogels consisting of (1,3)-(1,6) ß-Glucan and poly (N-isopropyl acrylamide) (PNIPAM) was synthesized by redox polymerization at room temperature. Tetramethylethylenediamine (TEMED) and potassium persulfate (KPS) were used as a redox pair. ß-glucan was methacrylated (MA-ß-Glucan) and used as a biodegradable and bio-compatible cross-linker to prepare ß-glucan-PNIPAM based temperature responsive hydrogels. Swelling behavior of the hydrogels at different temperatures was investigated. The 5-ASA release from the hydrogels was monitored using UV-VIS spectrophotometer at 37 °C. It is notable that, the swelling and release behaviors of the hydrogels significantly change depending on the hydrogel compositions and temperature. Their thermal stability was determined using thermogravimetric analysis (TGA), assuming the extent of intermolecular interaction between PNIPAM and ß-glucan is proportional to thermal stability, which increased with the amount of PNIPAM. Volume phase transition temperature (VPTT) of the hydrogels was precisely determined by derivative differential scanning calorimeter (DDSC). They possessed variable VPTT with the compositions. The presence of ß-glucan in the PNIPAM network brought VPTT closer to the body temperature (from 32.8 °C to 35.5 °C), indicating that the VPTT could be tuned by the hydrogel compositions. Their in-vivo biocompatibility was tested against WS1 human fibroblast cells in phosphate buffer saline (PBS, pH 7.4). It was demonstrated that, using MA-ß-glucan as a cross-linker resulted in more bio-compatible thermo-responsive hydrogels indicating the enhancement of hydrophilic ß-Glucan on the swollen hydrogel surface.

Genetic variants in cellular transport do not affect mesalamine response in ulcerative colitis.

BACKGROUND AND AIMS: Mesalamine is commonly used to treat ulcerative colitis (UC). Although mesalamine acts topically, in vitro data suggest that intracellular transport is required for its beneficial effect. Genetic variants in mucosal transport proteins may affect this uptake, but the clinical relevance of these variants has not been studied. The aim of this study was to determine whether variants in genes involved in cellular transport affect the response to mesalamine in UC. METHODS: Subjects with UC from a 6-week clinical trial using multiple doses of mesalamine were genotyped using a genome-wide array that included common exome variants. Analysis focused on cellular transport gene variants with a minor allele frequency >5%. Mesalamine response was defined as improvement in Week 6 Physician's Global Assessment (PGA) and non-response as a lack of improvement in Week 6 PGA. Quality control thresholds included an individual genotyping rate of >90%, SNP genotyping rate of >98%, and exclusion for subjects with cryptic relatedness. All included variants met Hardy-Weinberg equilibrium (p>0.001). RESULTS: 457 adults with UC were included with 280 responders and 177 non-responders. There were no common variants in transporter genes that were associated with response to mesalamine. The genetic risk score of responders was similar to that of non-responders (p = 0.18). Genome-wide variants demonstrating a trend towards mesalamine response included ST8SIA5 (p = 1x10-5). CONCLUSIONS: Common transporter gene variants did not affect response to mesalamine in adult UC. The response to mesalamine may be due to rare genetic events or environmental factors such as the intestinal microbiome.

A Biopredictive In Vitro Comparison of Oral Locally Acting Mesalazine Formulations by a Novel Dissolution Model for Assessing Intraluminal Drug Release in Individual Subjects.

Drug release and availability at the site of action are the major factors determining the clinical response for locally-acting gastrointestinal (GI) drug products. The present work focused on the prediction of site and extent of in vivo mesalazine release after oral administration to a variety of subjects using individualized in vitro drug release experiments. First, experiments mimicking GI passages in average adult subjects were performed. Then, results from a study screening fasted in vivo pH and transit profiles in individual subjects were translated into a novel in vitro dissolution model enabling to mimic individual GI pH-profiles and transit times with physiologically relevant dissolution media. A selection of monolithic and multiparticulate mesalazine formulations with pH-dependent and pH-independent drug release was screened with the novel dissolution model. Results of the study indicate that dosage form performance can be significantly different in individual subjects and highlight the importance of addressing individual physiological parameters relevant to intraluminal drug release when the aim is to predict the in vivo performance of locally-acting mesalazine formulations in individual patients. The novel in vitro dissolution approach thus represents a valuable tool for both improving individual oral therapy with locally-acting GI drug products and assessing bioequivalence of these formulations.

New mesalamine polymeric conjugate for controlled release: Preparation, characterization and biodistribution study.

Mesalamine (5-ASA) consists of the first-line therapy for the treatment of ulcerative colitis; however, it has low bioavailability, can cause several systemic adverse events, and has low treatment adherence due to the inconvenient dosing scheme. In this work, a new drug delivery system consisting of chondroitin sulfate linked to 5-ASA was synthesized using a carbodiimide as conjugating agent. The system was characterized by spectroscopic techniques (UV, ATR-FTIR, XRD, and NMR 1H) and thermal analysis (TG/DTG and DSC), suggesting the conjugation between the drug and the polymer. The in vitro release and the corresponding kinetics were also evaluated, revealing that approximately 40% of the drug linked was released at pH9 for up to 50h, following Higuchi's model. The conjugate did not show cytotoxicity for the human monocytic cell line at the doses tested, and an in vivo biodistribution study showed that the conjugate remained in the lower GIT for up to 8h with no uptake in the upper GIT. These data corroborate with the radiation found per segment of GIT and in blood. For this last test the conjugate was radiolabeled with Technetium-99m to allow the scintigraphy evaluation and radiation quantification. In conclusion, the polymeric conjugate was successfully synthesized and demonstrated a mucoadhesiveness on the colon as desired, thus supporting its potential use in the treatment of ulcerative colitis.