Vitamin C Improves Dasatinib Concentrations Under Hypochlorhydric Conditions of the Simulated Stomach Duodenum Model.

PURPOSE: pH-dependent drug-drug interactions (DDIs) with poorly soluble, weakly basic drugs may lead to clinical implications. Dasatinib is a tyrosine kinase inhibitor with reduced absorption in patients on acid-reducing agents (ARAs). The objective of this study is to investigate the influence of gastric pH on dasatinib supersaturation and determine if vitamin C (L-ascorbic acid) can improve dasatinib concentrations under simulated hypochlorhydric gastric conditions. METHODS: A dynamic, in vitro, multi-compartment, simulated stomach duodenum (SSD) model mimicking fluid volumes and transfer rates was used to investigate the concentration of BCS class IIb drugs versus time curves. Dasatinib and lamotrigine were explored under normal, fasted, simulated gastric fluids (pH 2) (FaSGF), hypochlorhydric simulated gastric fluids (pH 4.5) (FaSGFhypo) and FaSGFhypo with 1000 mg of vitamin C. RESULTS: Significant supersaturation of dasatinib was observed in the duodenum compartment of the SSD model in FaSGF. A 90% reduction in dasatinib AUC∞ was observed in FaSGFhypo. Upon addition of vitamin C to FaSGFhypo, drug concentrations were restored to those observed in FaSGF. Lamotrigine AUC∞ in the duodenal compartment were similar in both FaSGF and FaSGFhypo. The in vitro trends observed for dasatinib and lamotrigine are reflective of the trends observed in vivo in subjects receiving treatment with ARAs. CONCLUSIONS: The SSD model serves as a good in vitro tool for assessing the effect of pH-dependent DDIs on bioavailability of weakly basic drugs with solubility/ dissolution limited absorption. Vitamin C provides a promising approach for improving bioavailability of poorly soluble, weakly basic drugs in hypochlorhydric patients.

The Route to Palatable Fecal Microbiota Transplantation.

The community of symbiotic microorganisms that reside in our gastrointestinal tract is integral to human health. Fecal microbiota transplantation (FMT) has been shown to be highly effective in treating recurrent Clostridioides difficile infection (rCDI) and is now recommended by medical societies for patients suffering from rCDI who have failed to respond to conventional therapy. The main challenges with FMT are its accessibility, acceptability, lack of standardization, and regulatory complexity, which will be discussed in this review. Access to FMT is being addressed through the development of frozen and lyophilized FMT preparations that can be prepared at stool banks and shipped to the point of care. Both access and patient acceptance would be enhanced by oral FMT capsules, and there is potential to reduce capsule burden by utilizing colonic release capsules, targeting the site of disease. This review compares the efficacy of different FMT routes of administration: capsules, nasal feeding tubes, enemas, and colonoscopic infusions. FMT is considered investigational by the Food and Drug Administration. In effort to improve access to FMT, physicians may perform FMT outside of an investigational new drug application for treating CDI infections not responsive to standard therapies. The majority of FMT studies report only minor adverse effects; however, there is risk of transmission of infections.

Correction to: Fecal Microbiota Transplantation Capsules with Targeted Colonic Versus Gastric Delivery in Recurrent Clostridium difficile Infection: A Comparative Cohort Analysis of High and Low Dose.

The original version of the article unfortunately contained an error in article title. The corrected title is 'Fecal Microbiota Transplantation Capsules with Targeted Colonic Versus Gastric Delivery in Recurrent Clostridium difficile Infection: A Comparative Cohort Analysis of High and Low Dose'.

Fecal Microbiota Transplantation Capsules with Targeted Colonic Versus Gastric Delivery in Recurrent Clostridium difficile Infection: A Comparative Cohort Analysis of High and Lose Dose.

BACKGROUND: Fecal microbiota transplantation (FMT) is an effective therapy for recurrent Clostridium. difficile infection (rCDI). FMT capsules have emerged, and it is unknown if delivery location and dose impact efficacy. METHODS: We compared two cohorts of patients receiving two capsule formulations: gastric release (FMTgr) and targeted colonic release (FMTcr) at two different sites. Cohort A received FMTgr at (1) high dose: 60 capsules and low dose: 30 capsules. Patients in Cohort B received FMTcr at (1) high dose: 30 capsules (2) low dose: 10 capsules. Clinical cure rates and adverse events were monitored through week 8. Paired t-tests were used to compare diversity pre- and post-FMT. RESULTS: 51 rCDI patients were enrolled. Cohort A contained n = 20 and Cohort B contained n = 31. Overall cure at week 8 for FMTgr was 75% (15/20) compared to 80.6% for FMTcr, (25/31), p = 0.63. Both formulations were safe with no serious adverse events. FMTcr was superior at increasing gut microbial diversity. DISCUSSION: To our knowledge, this is the first study to compare targeted delivery of FMT capsules. While both capsules were safe and efficacious, microbial engraftment patterns were superior in FMTcr.

Risk Factors for Rescue Therapy in Crohn's Patients Maintained on Infliximab After Withdrawal of the Immunomodulator: A Long-Term Follow-Up.

BACKGROUND: Usefulness of thiopurine and scheduled infliximab combination therapy in non-immunomodulator (IM)-naïve Crohn's disease (CD) patients and the optimal length of dual therapy are still debated. AIMS: To determine proportion of patients developing disease flare requiring rescue therapy and risk factors associated with disease flare after de-escalation of IM from combination therapy. METHODS: Adult CD patients in clinical remission on combination therapy were identified from a large single-center database between 2002 and 2009. Patients who had their IM stopped in the absence of adverse events were included. Association between clinical and demographic variables and time until rescue therapy was analyzed using Cox-proportional hazard models. RESULTS: Forty-three CD patients on combination therapy in clinical remission at time of IM de-escalation were identified and followed up for a median duration of 61.6 months (range 5.4-129.5). Median duration of remission on combination therapy prior to IM de-escalation was 12.0 months (range 4-74). Thirty-one patients (72.1%) required rescue therapy during follow-up. On multivariable analysis, age at diagnosis < 16 years versus > 40 years (HR 4.55, 95% CI 1.18-17.62, p = 0.028), using methotrexate instead of azathioprine in combination with infliximab (HR 3.37, 95% CI 1.14, 9.96, p = 0.028), and duration of combination therapy < 6 months (HR 5.68, 95% CI 1.58, 20.36, p = 0.007) increased risk for rescue therapy. CONCLUSIONS: A large proportion of CD patients on combination therapy experienced a flare following IM withdrawal. Young age at diagnosis, short duration of combination therapy, and methotrexate use were independent predictors of the need for rescue therapy.

Assessment of Small Intestinal Transit Times in Ulcerative Colitis and Crohn's Disease Patients with Different Disease Activity Using Video Capsule Endoscopy.

Small intestinal transit times (SITT) influence drug bioavailability. This study aimed to compare SITT in Crohn's disease and ulcerative colitis patients with non-inflammatory bowel disease (IBD) and to determine influence of disease activity on transit times, and in addition, to establish the utility of small bowel video capsule endoscopy (SB-VCE) in investigation of SITT in IBD patients. A retrospective review was performed on consecutive patients who had undergone SB-VCE at a university hospital out-patient clinic. In total, 125 non-IBD patients, 55 Crohn's disease patients, and 23 ulcerative colitis patients were included. SITT were calculated from the first duodenal image to the first cecal image. Disease activity was assessed based on endoscopy results and inflammatory markers (calprotectin, C-reactive protein, erythrocyte sedimentation rate). SITT were longer in ulcerative colitis patients compared to non-IBD patients (median 264 min vs. 216 min, p = 0.010). Patients with active Crohn's disease (n = 33) also displayed prolonged SITT compared to non-IBD patients (median 253 min vs 216 min, p = 0.017) and patients with quiescent Crohn's disease (n = 22) (p = 0.005). SITT can be prolonged in IBD patients depending on disease activity which may alter the drug release profiles and clinical response to colonic drug delivery systems. SB-VCE is a simple, non-invasive tool that can be utilized in pharmacokinetic studies to understand drug bioavailability in different patient groups. Moreover, this variability in transit times needs to be simulated in dissolution testing for in vitro in vivo correlations.

Leveraging BCS in Development: A Case Study.

In this work, we discuss leveraging the Biopharmaceutics Classification System (BCS) in the development of edivoxetine HCl, a selective norepinephrine reuptake inhibitor. First, the biopharmaceutical and in vivo data are presented and discussed. Solubility studies indicate that edivoxetine HCl meets the BCS "highly soluble" criteria. To determine permeability classifications, in vitro intestinal Caco-2 epithelial cell model with and without cyclosporin A (CsA), a common P-glycoprotein (P-gp) inhibitor, were conducted. Pharmacokinetic (PK) data obtained across phase 1 and 2 clinical studies where single and multiple doses range from the lowest to the highest strength are presented. Neither the Caco-2 nor the in vivo data on their own were sufficient to conclusively classify edivoxetine as highly permeable. However, collectively the data were utilized to support high permeability and consequently BCS1 classification of edivoxetine HCl. BCS1 classification was leveraged throughout development to assess the risk associated with not conducting relative bioavailability (RBA) studies and avoiding bioequivalence (BE) studies. Examples are presented where formulation changes were made between phase I (drug in capsule/drug in bottle formulations) and phase II (tablet) trials in addition to phase III (tablet) and commercial (smaller tablet) without having to conduct any in vivo comparability studies. For the first change, BCS was leveraged to avoid conducting a RBA study even before obtaining official BCS classification. For the later change, official BCS1 classification was relied upon to avoid conducting a BE study.

A novel method for determining the solubility of small molecules in aqueous media and polymer solvent systems using solution calorimetry.

PURPOSE: To explore the application of solution calorimetry for measuring drug solubility in experimentally challenging situations while providing additional information on the physical properties of the solute material. METHODS: A semi-adiabatic solution calorimeter was used to measure the heat of dissolution of prednisolone and chlorpropamide in aqueous solvents and of griseofulvin and ritonavir in viscous solutions containing polyvinylpyrrolidone and N-ethylpyrrolidone. RESULTS: Dissolution end point was clearly ascertained when heat generation stopped. The heat of solution was a linear function of dissolved mass for all drugs (<10% RSD, except for chlorpropamide). Heats of solution of 9.8 ± 0.8, 28.8 ± 0.6, 45.7 ± 1.6 and 159.8 ± 20.1 J/g were obtained for griseofulvin, ritonavir, prednisolone and chlorpropamide, respectively. Saturation was identifiable by a plateau in the heat signal and the crossing of the two linear segments corresponds to the solubility limit. The solubilities of prednisolone and chlopropamide in water by the calorimetric method were 0.23 and 0.158 mg/mL, respectively, in agreement with the shake-flask/HPLC-UV determined values of 0.212 ± 0.013 and 0.169 ± 0.015 mg/mL, respectively. For the higher solubility and high viscosity systems of griseofulvin and ritonavir in NEP/PVP mixtures, respectively, solubility values of 65 and 594 mg/g, respectively, were obtained. CONCLUSION: Solution calorimetry offers a reliable method for measuring drug solubility in organic and aqueous solvents. The approach is complementary to the traditional shake-flask method, providing information on the solid properties of the solute. For highly viscous solutions, the calorimetric approach is advantageous.

Pediatric oral extemporaneous preparations and practices: International Pharmaceutical Federation (FIP) global study.

This publication is the first to report current, global, pediatric oral extemporaneous compounding practices. Complete survey responses were received from 470 participants actively involved in compounding across all the World Health Organization (WHO) regions. The survey addressed oral formulation of extemporaneous liquids, including the use of commercial or in-house vehicles, flavoring excipients, source of formulation recipes, and beyond use dates (BUDs). Over 90% of the survey participants prepared oral liquids. Solid dosage forms, comprising capsules and powder papers (sachets) were also frequently prepared for children, albeit to a lesser extent. The top 20 active pharmaceutical ingredients compounded for children, globally, were: omeprazole, captopril, spironolactone, propranolol, furosemide, phenobarbital, hydrochlorothiazide, ursodeoxycholic acid, sildenafil, melatonin, clonidine, enalapril, dexamethasone, baclofen, caffeine, chloral hydrate, trimethoprim, atenolol, hydrocortisone, carvedilol and prednisolone. Diuretics, drugs for acid-related disorders, and beta-blockers were the top three most frequently compounded classes per the WHO Anatomical Therapeutic Chemical (ATC) classification system. The principal need identified for the practice of extemporaneous compounding for children was the development of an international, open-access formulary that includes validated formulations, as well as updated compounding literature and guidelines. Furthermore, improved access to data from stability studies to allow compounding of formulations with extended BUDs.

Molecular dynamic simulations of ocular tablet dissolution.

Small tablets for implantation into the subconjunctival space in the eye are being developed to inhibit scarring after glaucoma filtration surgery (GFS). There is a need to evaluate drug dissolution at the molecular level to determine how the chemical structure of the active may correlate with dissolution in the nonsink conditions of the conjunctival space. We conducted molecular dynamics simulations to study the dissolution process of tablets derived from two drugs that can inhibit fibrosis after GFS, 5-fluorouracil (5-FU) and the matrix metalloprotease inhibitor (MMPi), ilomastat. The dissolution was simulated in the presence of simple point charge (SPC) water molecules, and the liquid turnover of the aqueous humor in the subconjunctival space was simulated by removal of the dissolved drug molecules at regular intervals and replacement by new water molecules. At the end of the simulation, the total molecular solvent accessible surface area of 5-FU tablets increased by 60 times more than that of ilomastat as a result of tablet swelling and release of molecules into solution. The tablet dissolution pattern shown in our molecular dynamic simulations tends to correlate with experimental release profiles. This work indicates that a series of molecular dynamic simulations can be used to predict the influence of the molecular properties of a drug on its dissolution profile and could be useful during preformulation where sufficient amounts of the drug are not always available to perform dissolution studies.

Characterisation of ilomastat for prolonged ocular drug release.

We are developing tablet dosage forms for implantation directly into the subconjunctival space of the eye. The matrix metalloproteinase inhibitor, ilomastat, has previously been shown to be efficacious at suppressing scarring following glaucoma filtration surgery (GFS). We report on the physical characterisation of ilomastat which is being developed for ocular implantation. Since ilomastat is being considered for implantation it is necessary to examine its polymorphs and their influence on aspects of the in vitro drug release profile. X-ray powder diffraction identified two polymorphs of ilomastat from different commercial batches of the compound. Tablets were prepared from the two different polymorphs. Isothermal perfusion calorimetry was used to show that amorphous content is not increased during tablet formulation. The melting points of the two polymorphs are 188 and 208°C as determined by differential scanning calorimetry. Utilising single crystal X-ray diffraction, the structural conformations and packing arrangements of the different polymorphs were determined. The orthorhombic crystal crystallised as a monohydrate while the second monoclinic crystal form is non-solvated. Ilomastat tablets prepared from the two different solid forms exhibited similar drug release profiles in vitro under conditions mimicking the aqueous composition, volume and flow of the subconjunctival space after GFS. This suggests that a reproducible dose at each time point during release after implantation should be achievable in vivo with ilomastat tablets prepared from the two polymorphs identified.

Drug Physicochemical Properties and Capsule Fill Determine Extent of Premature Gastric Release from Enteric Capsules.

Intrinsically, enteric capsule shells offer several advantages compared to coating of dosage forms with enteric polymers. We undertook a systematic investigation to elucidate capsule-fill parameters that may result in premature gastric drug release from Vcaps® Enteric capsules (Lonza CHI, Morristown, NJ, USA). Four model drugs with different ionization and solubility profiles were investigated: acetaminophen, ketoprofen, trimethoprim and atenolol. Different fill loads, diluents and drug-to-diluent ratios were explored. Enteric capsules were filled with drug or drug and diluent powder mix and underwent USP II dissolution testing using mini-vessels and paddles. Capsules were tested in pH 2 (0.01 M HCl) or pH 4.5 (3.2 × 10-5 M HCl) 200 mL acid media to simulate normal, fasted or hypochlorhydric gastric pH, respectively. Acetaminophen, trimethoprim and atenolol displayed premature gastric drug release from enteric capsules. The extent of premature release was dependent on drug solubility, ionization profile and capsule-fill level. At 100 mg drug-fill level, acetaminophen, trimethoprim and atenolol gave rise to 10.6, 12.2 and 83.1% drug release, respectively, in normal, fasted, gastric fluids. Diffusion layer pH of trimethoprim and atenolol in pH 2 media was determined to be pH 6.3 and 10.3, respectively. Upon increasing capsule-fill load using microcrystalline cellulose as a diluent, a significant reduction in premature gastric release was observed. However, including mannitol as a diluent was only effective at decreasing premature drug release at a low drug-to-diluent ratio. Systematic in vitro screening of enteric capsule fills needs to be conducted to ensure that drug product performance is not compromised.

Intra- and inter-subject variability in gastric pH following a low-fat, low-calorie meal.

Food can alter drug bioavailability through gastric pH changes. Time spent at gastric pH ranges is reported here, including variability data following ingestion of a light, mixed, 260 kcal meal. pH data was obtained for 20 healthy subjects undergoing SmartPill™ wireless motility capsule investigations on three separate visits. Gastric phase pH was sorted into pH < 2, 2-3, 3-4, 4-5 and > 5. All visits and all subjects were pooled to determine median time (25-75th percentiles) in minutes. Gastric emptying time was 176 (137-205) min with the majority of time, 111 (67 - 163), spent at pH < 2. Times spent at pH 2-3 and 3-4 were similar: 17 (5.7 - 35.6) and 18 (7.2-29.3). Time spent at pH 4-5 was 9 (1.3-20.6) and at pH > 5 was 0.7 (0-4.4). Intra-subject variability as determined by robust coefficient of variation (RCV)% was 30 % for pH < 2, 57 % for pH 2-3, 71 % for pH 3-4, 106 % for pH 4-5 and 144 % for pH > 5. Inter-subject variability RCV% was 49 % for pH < 2, 89 % for pH 2-3, 54 % for pH 3-4, 97 % for pH 4-5 and 148 % for pH > 5. Inter-subject variability can be up to approximately twofold higher than intra-subject variability at the lower pH ranges.

A dual pH and microbiota-triggered coating (Phloral™) for fail-safe colonic drug release.

Enteric-coated dosage forms are widely used for targeting the ileo-colonic region of the gastrointestinal (GI) tract. However, accurate targeting is challenging due to intra- and inter-individual variability in intestinal paramaters such as fluid pH and transit times, which occasionally lead to enteric coating failure. As such, a unique coating technology (Phloral™), which combines two independent release mechanisms - a pH trigger (Eudragit® S; dissolving at pH 7) and a microbiota-trigger (resistant starch), has been developed, offering a fail-safe approach to colonic targeting. Here, we demonstrate that the inclusion of resistant starch in the coating does not affect the pH mediated drug release mechanism or the robustness of the coating in the upper GI tract. In order to make the resistant starch more digestible by bacterial enzymes, heat treatment of the starch in the presence of butanol was required to allow disruption of the crystalline structure of the starch granules. Under challenging conditions of limited exposure to high pH in the distal small intestine fluid and rapid transit through the colon, often observed in patients with inflammatory bowel disease, particularly in ulcerative colitis, this dual-trigger pH-enzymatic coating offers a revolutionary approach for site specific drug delivery to the large intestine.

Community pharmacists' understanding and perceptions of FDA therapeutic equivalence standards.

BACKGROUND: Pharmacists need to demonstrate knowledge of and have confidence in Food and Drug Administration (FDA) therapeutic equivalence (TE) standards to improve acceptance of generic medicines amongst patients and other healthcare professionals. OBJECTIVE: To evaluate community pharmacists' understanding, interpretation and perceptions of the FDA TE standards to identify if further education is needed on this topic. METHODS: An anonymous, 13-item survey was piloted and then distributed by e-mail to a random sample of 287 Indiana community pharmacists. The 5-min survey included demographic, knowledge-based, and perception-based questions on FDA TE criteria that participants were given one week to complete. Participants completed the survey using a Web-based survey tool (Qualtrics). RESULTS: 192 pharmacists completed the survey achieving a response rate of 66.9%. Only 7.3% of respondents correctly identified FDA bioequivalence criteria for approval of generic drug products. Two questions presented TE codes from the Orange Book and asked respondents to identify if a pair of drug products were therapeutically equivalent: 62.6% and 61.0% of respondents answered correctly. However, 89.4% of respondents correctly indicated that the Orange Book is the location of FDA TE evaluations. 74.9% of responding pharmacists indicated a positive perception of the rigor of FDA approval standards associated with generic medications and 66.0% believed that generic drug products made by different manufacturers are of similar quality. CONCLUSIONS: The results suggest that community pharmacists need additional education on the interpretation of TE codes and FDA bioequivalence criteria for approval of generic drug products. The safety and efficacy of generics are often questioned by patients and physicians. It is important for pharmacists to be knowledgeable of FDA TE standards as they are experts in medicines and need to be confident with the criteria to effectively convey them to patients and healthcare professionals.

A Simulated Stomach Duodenum Model Predicting the Effect of Fluid Volume and Prandial Gastric Flow Patterns on Nifedipine Pharmacokinetics From Cosolvent-Based Capsules.

Nifedipine is a Biopharmaceutics Classification System class II drug displaying large variability in absorption even when administered as immediate-release soft gelatin capsules of a cosolvent formulation. This in vitro study sought to understand the reasons behind variability in nifedipine absorption, how it can be minimized, and if it can be predicted using in vitro models. A dynamic in vitro simulated stomach duodenum model was used to explore drug concentration-time profiles of nifedipine soft gelatin capsules under conditions simulating how patients take their medicines. Specifically, the effect of prandial gastric emptying patterns and fluid volume administration (250 mL vs. 50 mL water) were investigated. Significant supersaturation of nifedipine was observed. While administration of large and small water volumes gave rise to a similar Cmax and area under the curve (AUC∞), the coefficient of variation in AUC was 4.8% and 49%, respectively, which can be attributed to differences in precipitation kinetics. Fasting and fed gastric emptying patterns also gave rise to a similar AUC; however, Cmax was significantly lower in the fed state. These trends are consistent with previously published in vivo results in healthy volunteers. The simulated stomach duodenum provides a good discriminative screening tool for predicting trends in drug concentration profiles of Biopharmaceutics Classification System class II drugs.

Gut instincts: explorations in intestinal physiology and drug delivery.

We need to look beyond our gut instincts to use information on "simple" intestinal physiological parameters as they have been presented to us in the past. Here we present a discussion on such parameters, old and new, and ask how much we really understand them. Behaviour of drugs and delivery systems in the intestine depends on many physiological factors including fluid volume, fluid composition, transit, motility, bacteria and pH, which are further influenced by food, gender and age. These are often considered well understood, but their true variability and idiosyncrasies are not fully appreciated or utilised in intestinal dosage form design or in vitro testing. There are still many unknowns in these areas. The distal gut especially has been neglected, and the influence of disease is often ignored. As pharmaceutics moves forward into the molecular era an understanding of the role of cellular mechanisms of transporters and metabolic enzymes is important, but the basics must not be forgotten. This discussion on intestinal physiology is utilised to address those areas which require further research and understanding, and new technologies are highlighted. Better understanding of the fundamental information available can open new avenues for research and pave the way for the future of gastrointestinal drug delivery.

Impairment of the in vitro drug release behaviour of oral modified release preparations in the presence of alcohol.

Recently, there has been concern by regulatory authorities of the risk of alcohol-induced dose dumping of oral modified release (MR) formulations. The aim of this work was to use in vitro dissolution methodology to investigate the vulnerability of MR products to alcohol under different physiological conditions of the upper gastrointestinal tract. A variety of dissolution scenarios with ethanol concentrations in the range of 5-40% v/v were explored. Mesalazine (5-aminosalicylic acid) was selected as the model drug and the release behaviour of three commercially available MR, monolithic and multi-particulate preparations with pH-dependent or independent release mechanisms was evaluated (Salofalk, Asacol and Pentasa). Each product was found to have a distinctive release profile and behaved differently in the scenarios screened. In the case of Pentasa, complete dose dumping occurred on exposure to 40% ethanol in acid for 2h. Asacol, however, displayed a contrarian trend with drug release being substantially delayed in small intestinal media after pre-exposure to acid/ethanol for the same duration. Salofalk underwent accelerated drug release in the presence of ethanol in the dissolution media, with unexpected trends observed between the different scenarios. For the three preparations explored, there appears to be a complex interplay between the various formulation variables and ethanol in the dissolution media. The unpredictable release profiles under the different conditions makes it necessary to screen several in vitro scenarios of ethanol exposure for each preparation before a decision is reached on its susceptibility to drug release impairment on consumption with ethanol.

LC-MS analysis to determine the biodistribution of a polymer coated ilomastat ocular implant.

Ilomastat is a matrix metalloproteinase inhibitor (MMPi) that has shown the potential to inhibit scarring (fibrosis) by mediating healing after injury or surgery. A long lasting ocular implantable pharmaceutical formulation of ilomastat is being developed to mediate the healing process to prevent scarring after glaucoma filtration surgery. The ilomastat implant was coated with water permeable and biocompatible phosphoryl choline polymer (PC1059) displayed extended slow release of ilomastat in vitro and in vivo. The ocular distribution of ilomastat from the implant in rabbits at day 30 post surgery was determined by the extraction of ilomastat and its internal standard marimastat from the ocular tissues, plasma, aqueous humour and vitreous fluid followed by capillary-flow liquid chromatography (cap-LC), the column effluent was directed into a triple quadrupole mass spectrometer operating in product scan mode. The lower limits of quantification (LLOQs) were 0.3 pg/µL for ocular fluids and plasma, and 3 pg/mg for ocular tissues. The extraction recoveries were 90-95% for ilomastat and its internal standard from ocular tissues. Ilomastat was found in ocular fluids and tissues at day 30 after surgery. The level of ilomastat was 18 times higher in the aqueous humour than vitreous humour. The concentration ranking of ilomastat in the ocular tissues was sclera > bleb conjunctiva > conjunctiva (rest of the eye) > cornea. Mass spectrometry analysis to confirm the presence of ilomastat in the ocular tissues and fluids at day 30 post-surgery establishes the extended release of ilomastat can be achieved in vivo, which is crucial information for optimisation of the ilomastat coated implant.

Methotrexate Polyglutamate Monitoring in Patients With Crohn's Disease.

Methotrexate is an efficacious immunosuppressant for induction and maintenance of remission in Crohn's disease. The goal of this pilot study was to determine whether total or individual methotrexate glutamate levels (MTXGlun ) in red blood cells correlate with disease activity and adverse events in Crohn's disease. A cross-sectional study was undertaken with 12 patients on a stable dose of 25 mg weekly methotrexate (oral or subcutaneous). Clinical disease activity was assessed by the Harvey-Bradshaw Index (HBI), and biologic disease activity was measured by inflammatory markers. Concentrations of individual MTXGlun levels were measured in red blood cells (RBCs) using high-performance liquid chromatography-mass spectrometry. No association was observed between RBC individual (MTXGlun ) or total methotrexate glutamate concentrations and clinical disease activity (HBI score) or inflammatory markers or adverse events. Although Crohn's disease patients in remission appeared to generally have higher RBC total longer-chain methotrexate polyglutamate (MTXGlu3+4+5 ) concentrations compared with those with active disease, a definitive association between RBC MTXGlu3+4+5 levels and clinical disease activity could not be established. Larger longitudinal studies in patients with diverse disease activity are needed to establish the value of MTXGlun levels as indicators of treatment efficacy and clinical outcome.