Inosine monophosphate dehydrogenase (IMPDH); de novo purine synthesis

Inosine monophosphate dehydrogenase is a crucial enzyme that T and B lymphocytes use for the de novo production of guanosine nucleotides [1].

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Mycophenolic acid, the active metabolite of mycophenolate mofetil, is a non-competitive, reversible inhibitor of inosine monophosphate dehydrogenase (IMPDH). Inhibition of IMPDH blocks the de novo synthesis of guanosine nucleotides which are necessary substrates for DNA and RNA synthesis. Unlike other cell types which can use the salvage pathway, B and T lymphocytes are dependent upon the de novo pathway for the generation of guanosine. Data from in vitro studies indicate that mycophenolic acid and/or mycophenolate mofetil inhibit mixed lymphocyte responses and human peripheral blood lymphocyte proliferation induced by a variety of mitogens and antigens. Mycophenolic acid decreases intracellular pools of guanosine triphosphate (GTP) and deoxyguanosine triphosphate (dGTP) in mitogen-stimulated human peripheral blood monocytes or T lymphocytic cell lines but has no effect on GTP concentrations in human neutrophils [2].

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Aims: Nucleotide depletion induced by the immunosuppressant mycophenolate mofetil (MMF) has been shown to exert neuroprotective effects. It remains unclear whether nucleotide depletion directly counteracts neuronal demise or whether it inhibits microglial or astrocytic activation, thereby resulting in indirect neuroprotection.
Methods: Effects of MMF on isolated microglial cells, astrocyte/microglial cell co-cultures and isolated hippocampal neurones were analysed by immunocytochemistry, quantitative morphometry, and elisa.
Results: We found that: (i) MMF suppressed lipopolysaccharide-induced microglial secretion of interleukin-1β, tumour necrosis factor-α and nitric oxide; (ii) MMF suppressed lipopolysaccharide-induced astrocytic production of tumour necrosis factor-α but not of nitric oxide; (iii) MMF strongly inhibited proliferation of both microglial cells and astrocytes; (iv) MMF did not protect isolated hippocampal neurones from excitotoxic injury; and (v) effects of MMF on glial cells were reversed after treatment with guanosine.
Conclusions: Nucleotide depletion induced by MMF inhibits microglial and astrocytic activation. Microglial and astrocytic proliferation is suppressed by MMF-induced inhibition of the salvage pathway enzyme inosine monophosphate dehydrogenase. The previously observed neuroprotection after MMF treatment seems to be indirectly mediated, making this compound an interesting immunosuppressant in the treatment of acute central nervous system lesions [4].

In an ACI-to-Lewis rat heterotopic cardiac transplant model, treatment of Mycophenolate mofetil at doses of 20 mg/kg and 40 mg/kg leads to a prolongation of graft survival, with median survival time (MST) of 14.5 days and 18.5 days, respectively. In bleomycin (BLM)-induced scleroderma mouse model, Mycophenolate mofetil reduces inflammatory-cell infiltration, tissue hydroxyproline content and dermal thickness.

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Mycophenolate mofetil has been shown to have efficacy in several animal models of transplantation (including cardiac, hepatic, pancreatic islet and renal). Mycophenolate mofetil was effective in preventing rejection or reversing ongoing rejection in rodent cardiac and canine renal allograft transplantation. However, the drug was only marginally effective in concordant and was ineffective in discordant cardiac xenograft transplantation. In the rat renal allograft model, mycophenolate mofetil effectively attenuated functional, morphological and immunohistological changes (significant reductions in proteinuria, glomerulosclerosis, arterial obliteration, macrophage and lymphocyte infiltration and expression of adhesion molecules and cytokines) associated with chronic rejection. The drug has also been shown to inhibit antibody production in rats and in humans. In rodent studies, mycophenolate mofetil was associated with the induction of donor-specific tolerance to grafted atrial tissue after cardiac allograft transplantation and to grafted thyroid tissue or injected spleen cells after pancreatic islet allograft transplantation [2].

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Mycophenolate mofetil is an ester prodrug of the active immunosuppressant mycophenolic acid. It is a noncompetitive, selective and reversible inhibitor of inosine monophosphate dehydrogenase, an important enzyme in the de novo synthesis of guanosine nucleotides in T and B lymphocytes. Mycophenolate mofetil and/or mycophenolic acid inhibit the proliferation of lymphocytes and the production of antibodies induced by a variety of mitogens and antigens. Mycophenolate mofetil is also active in several animal models of transplantation and has produced effects in animals that indicate that it may inhibit the chronic rejection process. Mycophenolate mofetil has been compared with azathioprine or placebo in 3 large, randomised, double-blind, multicentre trials as part of combination immunosuppression therapy with cyclosporin and corticosteroids. Compared with either placebo or azathioprine (1 to 2 mg/kg/day or 100 to 150 mg/day), mycophenolate mofetil 2 or 3 g/day was associated with a significantly lower proportion of patients experiencing acute rejection or treatment failure during the first 6 months after transplantation. Mycophenolate mofetil also tended to be associated with a lower proportion of patients who required a full course of antirejection therapy. However, the proportion of patients who died or who had graft loss was similar between all of the treatment groups. There are currently no data regarding the effects of mycophenolate mofetil on long term patient or graft survival, which are important clinical outcomes in assessing its place in the management of renal transplantation. Clinical trials are also needed to evaluate mycophenolate mofetil in specific patient populations (e.g. repeat renal transplant patients or highly sensitised patients), to determine its efficacy in alternative immunosuppressive protocols and to investigate its use in the transplantation of other solid organs. In summary, mycophenolate mofetil appears to be an attractive new agent in the prevention of graft rejection in renal transplant recipients that has shown superior efficacy to azathioprine. Although long term clinical outcome data are required, mycophenolate is a potentially important advance in transplant immunosuppression [2].

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Background: T lymphocytes induce the transformation of fibroblasts into myofibroblasts, the main mediators of fibrogenesis. The inosine 5'-monophosphate dehydrogenase inhibitor mycophenolate mofetil (MMF) and the anti-CD25 monoclonal antibody daclizumab (DCZ) have been reported to suppress the proliferation of T lymphocytes.
Aim: To evaluate the preventive effects of MMF and DCZ in early stages of bleomycin (BLM)-induced scleroderma.
Methods: This study involved five groups of Balb/c mice (n = 10 per group). Mice in four of the groups were injected subcutaneously (SC) with BLM [100 μg/day in 100 μL phosphate-buffered saline (PBS)] for 4 weeks; the remaining (control) group received only 100 μL PBS. Three of the BLM-treated groups also received either intraperitoneal MMF 50 or 150 mg/kg/day, or SC DCZ 100 μg/week. At the end of the fourth week, all mice were killed, and blood and tissue samples were obtained for further analysis.
Results: In the BLM-treated group, increases were seen in inflammatory-cell infiltration, α-smooth muscle actin-positive (α-SMA+) fibroblastic cell count, tissue hydroxyproline content, and dermal thickness. Dermal fibrosis was histopathologically prominent. In BLM-treated mice also given MMF or DCZ, inflammatory-cell infiltration, tissue hydroxyproline content and dermal thickness were decreased. In the MMF groups, decreases were also noted in α-SMA+ fibroblastic cell count.
Conclusion: In this BLM-induced dermal fibrosis model, MMF and DCZ treatments prevented the development of dermal fibrosis. Further studies are needed to evaluate whether targeting T lymphocytes is effective in resolving pre-existing fibrosis in human scleroderma [5].

Analyses of microglial and astrocytic apoptosis and proliferation [4]
Microglial cells or astrocytes treated with Mycophenolate MofetilMMF or incubated in culture medium were used to determine the possible toxic concentration range of Mycophenolate Mofetil/MMF. Apoptotic cells were visualized by immunocytochemical demonstration of activated caspase-3. Proliferation studies on microglial cells were performed in astrocyte/microglial cell co-cultures because significant microglial proliferation was only obtained in the presence of astrocytes. Stimulation of isolated microglial cells with LPS or macrophage-colony stimulating factor alone did not induce significant proliferative activity (data not shown). To analyse proliferation of microglial cells bromo-desoxy-uridine (BrdU; 0.01 mM) was added to the culture medium for 16 h prior to fixation. Foetal calf serum (1–10%) or corticotrophin releasing factor (CRF, 10 µM) for 48 h were used to stimulate proliferation in isolated astrocyte cultures, and BrdU (0.01 mM) was added 16 h prior to fixation. The proliferation index was calculated as the percentage of proliferating cells related to the total number of cells.

Animals and experimental protocols [5]
Fifty specific‐pathogen‐free female Balb/c mice, 6 weeks old and weighing 20–25 g, were used for the experimental procedures.
Defined areas of the lower back skins of the mice were shaved for subcutaneous injections. Mice in the control group received 100 μL/day phosphate‐buffered saline (PBS) subcutaneously (SC) to the shaved back skin. To induce dermal fibrosis, the remaining four groups received BLM 100 μg dissolved in 100 μL PBS and sterilized by filtration (0.2 μm filter) to the shaved skin on the back. Two groups of these BLM‐treated mice were also injected either intraperitoneally with MMF 50 or 150 mg/kg/day dissolved in 100 μL and 300 μL saline containing 0.4% Tween 80 and 0.9% benzyl alcohol, respectively, and a third BLM‐treated group was given DCZ 100 μg (100 μL) SC once weekly.

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Dissolved in 0.5% methylcellulose water; 40 mg/kg; i.v. administration
Lewis rats with abdominal vascularized heterotopic cardiac transplantation

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Clinical Efficacy [2]
Initial noncomparative trials helped to determine the efficacy of mycophenolate mofetil and provided the appropriate dosage regimens for use in larger clinical trials. Three randomised, double-blind, multicentre trials have been conducted comparing mycophenolate mofetil with either placebo or azathioprine as part of combination therapy (with cyclosporin and corticosteroids) for the prevention of renal transplant rejection. Acute rejection or treatment failure (premature withdrawal from the study for any reason) during the first 6 months after transplantation occurred in significantly fewer patients receiving mycophenolate mofetil 2 or 3 g/day (range 30.3 to 38.8%) than either placebo (56.0%), or azathioprine 1 to 2 mg/kg/day (47.6%) or 100 to 150 mg/day (50%). The proportion of patients who required full courses of antirejection therapy (corticosteroids and/or anti-lymphocyte therapy) during the first 6 months post-transplant also tended to be lower in patients who received mycophenolate mofetil (range 21.1 to 31%) than either placebo (51.8%) or azathioprine (44.5 and 46%) recipients although the differences were not statistically significant. There were no differences between any of the treatment groups in terms of graft loss or patient survival at 6 or 12 months. There are currently no data on the effect of mycophenolate mofetil on long term patient or renal graft survival. Subgroup analysis of one multicentre study revealed that African-Americans receiving mycophenolate mofetil 3 g/day tended to have a lower rate of biopsy-proven acute rejection and/or treatment failure than those receiving 2 g/day. The use of mycophenolate mofetil in children is limited to a single report involving 14 patients. Data regarding the use of mycophenolate mofetil in the treatment of acute rejection are limited but initial results are promising. In patients with biopsy-proven rejection, mycophenolate mofetil 3 g/day was associated with a significantly lower frequency of subsequent biopsy-proven rejection or treatment failure than high dose intravenous corticosteroids (29 vs 51%).

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Dosage and Administration [2]
The initial recommended dosage of mycophenolate mofetil for the prevention of renal transplant rejection is lg twice daily to be initiated within 72 hours of transplantation as part of a combination regimen with cyclosporin and corticosteroids. Although dosages of up to 3 g/day have been used, they were less well tolerated than 2 g/day and there was no difference in clinical efficacy between these dosages. In patients with glomerular filtration rate <25 ml/min (1.5 L/h)/ 1.73m dosages should not exceed 2 g/day. Dosage adjustments in patients with delayed graft function are not required.

Absorption, Distribution and Excretion
Mycophenolate mofetil is rapidly absorbed in the small intestine. The maximum concentration of its active metabolite, MPA, is attained 60 to 90 minutes following an oral dose. The average bioavailability of orally administered mycophenolate mofetil in a pharmacokinetic study of 12 healthy patients was 94%. In healthy volunteers, the Cmax of mycophenolate mofetil was 24.5 (±9.5)μg/mL. In renal transplant patients 5 days post-transplant, Cmax was 12.0 (±3.82) μg/mL, increasing to 24.1 (±12.1)μg/mL 3 months after transplantation. AUC values were 63.9 (±16.2) μg•h/mL in healthy volunteers after one dose, and 40.8 (±11.4) μg•h/mL, and 65.3 (±35.4)μg•h/mL 5 days and 3 months after a renal transplant, respectively. The absorption of mycophenolate mofetil is not affected by food.
A small amount of drug is excreted as MPA in the urine (less than 1%). When mycophenolate mofetil was given orally in a pharmacokinetic study, it was found to be 93% excreted in urine and 6% excreted in feces. Approximately 87% of the entire administered dose is found to be excreted in the urine as MPAG, an inactive metabolite.
The volume of distribution of mycophenolate mofetil is 3.6 (±1.5) to 4.0 (±1.2) L/kg.
Plasma clearance of mycophenolate mofetil is 193 mL/min after an oral dose and 177 (±31) mL/min after an intravenous dose.
/Absorption/ is rapid and extensive after oral administration.
In 12 healthy volunteers, the mean absolute bioavailability of oral mycophenolate mofetil relative to intravenous mycophenolate mofetil (based on MPA AUC) was 94%. The area under the plasma-concentration time curve (AUC) for MPA appears to increase in a dose-proportional fashion in renal transplant patients receiving multiple doses of mycophenolate mofetil up to a daily dose of 3 g.
Protein binding: To plasma albumin: High (97% for mycophenolic acid (MPA) at concentration ranges normally seen in stable renal transplant patients). At higher mycophenolic acid glucuronide (MPAG) concentrations (e.g., in patients with renal impairment or delayed graft function), binding of MPA may be decreased as a result of competition between MPA and MPAG for binding sites.
The mean (+/-SD) apparent volume of distribution of MPA in 12 healthy volunteers is approximately 3.6 (+/-1.5) and 4.0 (+/-1.2) L/kg following intravenous and oral administration, respectively. MPA, at clinically relevant concentrations, is 97% bound to plasma albumin. MPAG is 82% bound to plasma albumin at MPAG concentration ranges that are normally seen in stable renal transplant patients; however, at higher MPAG concentrations (observed in patients with renal impairment or delayed renal graft function), the binding of MPA may be reduced as a result of competition between MPAG and MPA for protein binding. Mean blood to plasma ratio of radioactivity concentrations was approximately 0.6 indicating that MPA and MPAG do not extensively distribute into the cellular fractions of blood.
For more Absorption, Distribution and Excretion (Complete) data for MYCOPHENOLATE MOFETIL (9 total), please visit the HSDB record page.

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Metabolism / Metabolites
After both oral and intravenous administration mycophenolate mofetil is entirely metabolized by liver carboxylesterases 1 and 2 to mycophenolic acid (MPA), the active parent drug. It is then metabolized by the enzyme glucuronyl transferase, producing the inactive phenolic glucuronide of MPA (MPAG). The glucuronide metabolite is important, as it is then converted to MPA through enterohepatic recirculation. Mycophenolate mofetil that escapes metabolism in the intestine enters the liver via the portal vein and is transformed to pharmacologically active MPA in the liver cells.N-(2-carboxymethyl)-morpholine, N-(2-hydroxyethyl)-morpholine, and the N-oxide portion of N-(2-hydroxyethyl)-morpholine are additional metabolites of MMF occurring in the intestine as a result of liver carboxylesterase 2 activity. UGT1A9 and UGT2B7 in the liver are the major enzymes contributing to the metabolism of MPA in addition to other UGT enzymes, which also play a role in MPA metabolism. The four major metabolites of MPA are 7-O-MPA-β-glucuronide (MPAG, inactive), MPA acyl-glucuronide (AcMPAG), produced by uridine 5ʹ-diphosphate glucuronosyltransferases (UGT) activities, 7-O-MPA glucoside produced via UGT, and small amounts 6-O-des-methyl-MPA (DM-MPA) via CYP3A4/5 and CYP2C8 enzymes.
Following oral and intravenous dosing, mycophenolate mofetil undergoes complete metabolism to MPA /mycophenolic acid/, the active metabolite. Metabolism to MPA occurs presystemically after oral dosing. MPA is metabolized principally by glucuronyl transferase to form the phenolic glucuronide of MPA (MPAG) which is not pharmacologically active. In vivo, MPAG is converted to MPA via enterohepatic recirculation. The following metabolites of the 2- hydroxyethyl-morpholino moiety are also recovered in the urine following oral administration of mycophenolate mofetil to healthy subjects: N-(2-carboxymethyl)-morpholine, N-(2- hydroxyethyl)-morpholine, and the N-oxide of N-(2-hydroxyethyl)-morpholine.

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Biological Half-Life
The average apparent half-life of mycophenolate mofetil is 17.9 (±6.5) hours after oral administration and 16.6 (±5.8) hours after intravenous administration.
For mycophenolic acid (MPA):Mean apparent: Approximately 17.9 hours after oral administration and 16.6 hours after intravenous administration.
Mean (+/-SD) apparent half-life and plasma clearance of MPA are 17.9 (+/-6.5) hours and 193 (+/-48) mL/min following oral administration and 16.6 (+/-5.8) hours and 177 (+/-31) mL/min following intravenous administration, respectively.

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Pharmacokinetic Properties [2]
Mycophenolate mofetil is well absorbed after oral administration and is rapidly converted to the active metabolite mycophenolic acid. The area under the plasma concentration-time curve (AUC) is generally proportional to dosage; however, there is some interpatient variation in values. The AUC and peak plasma concentration (Cmax) of mycophenolic acid are approximately 50% higher in stable renal transplant patients (>3 months post-transplantation) than in patients during the immediate post-transplant period.

Mycophenolic acid is primarily eliminated (≈87%) in the urine as mycophenolic acid glucuronide; 6% is eliminated in the faeces. The mean ‘apparent’ half-life and plasma clearance of mycophenolic acid are 17.9 hours and 11.6 L/h, respectively, after oral administration.

The AUC of mycophenolic acid and its glucuronide metabolite were higher in patients with renal impairment than in patients with normal renal function following single dose administration. However, the pharmacokinetic s of mycophenolic mofetil after a single dose are not altered in patients with cirrhosis. There are limited data in children but AUC and Cmax of mycophenolic acid appear to rise with increasing age.

Protein Binding
The protein binding of mycophenolic acid, the metabolite of mycophenolate mofetil, is 97% and it is mainly bound to albumin. MPAG, the inactive metabolite, is 82% bound to plasma albumin at normal therapeutic concentrations. At elevated MPAG concentrations due to various reasons, including renal impairment, the binding of MPA may be decreased due to competition for binding.

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Mycophenolate mofetil (the morpholinoethyl ester of mycophenolic acid) inhibits de novo purine synthesis via the inhibition of inosine monophosphate dehydrogenase. Its selective lymphocyte antiproliferative effects involve both T and B cells, preventing antibody formation. Mycophenolate mofetil has immunosuppressive effects alone, but is used most commonly in combination with other immunosuppressants. Mycophenolate mofetil, in combination with cyclosporin and corticosteroids, has been studied in large, randomised clinical trials involving nearly 1500 renal allograft transplant recipients. These trials demonstrated that mycophenolate mofetil is significantly more effective in reducing treatment failure and acute rejection episodes than placebo or azathioprine. Additionally, mycophenolate mofetil may be able to reduce the occurrence of chronic rejection.
Mycophenolate mofetil is relatively well tolerated. The most common adverse effect reported is gastrointestinal intolerance; haematological aberrations have also been noted. The reversible cytostatic action of mycophenolate mofetil allows for dose adjustment or discontinuation, preventing serious toxicity or an overly suppressed immune system. Cytomegalovirus tissue invasive disease and the development of malignancies are concerns that merit evaluation in long term follow-up studies.
Mycophenolate mofetil does not cause the adverse effects typically associated with other commercially available immunosuppressant medications such as nephrotoxicity, hepatotoxicity, hypertension, nervous system disturbances, electrolyte abnormalities, skin disorders, hyperglycaemia, hyperuricaemia, hypercholesterolaemia, lipid disorders and structural bone loss.
Based on preliminary information, a positive benefit-risk ratio has been demonstrated with the use of mycophenolate mofetil in the prophylaxis of rejection in cadaveric renal allograft transplantation. Data from studies in other types of organ transplants are promising, but are too limited to draw clear conclusions. Long term follow-up studies are required to confirm these observations. Although mycophenolate mofetil is expensive, the beneficial effects on the reduction of rejection, treatment failure and related expenses suggest that it is most likely to be cost effective.[1]

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Tolerability [2]
Rates of adverse events associated with mycophenolate mofetil appear to be dose related: 2 g/day is generally better tolerated than 3 g/day. Gastrointestinal (diarrhoea, vomiting), haematological and lymphatic (leucopenia, anaemia), and infectious (sepsis, opportunistic infections) events are most common. Diarrhoea and sepsis (most commonly cytomegalovirus viraemia) were slightly more common in patients receiving mycophenolate mofetil than in those receiving azathi-oprine. There was also an increased proportion of patients with leucopenia after treatment with mycophenolate mofetil 3 g/day compared with azathioprine treatment. The overall risk of malignancies associated with mycophenolate mofetil was similar to that of azathioprine.

[1]. Preliminary risk-benefit assessment of mycophenolate mofetil in transplant rejection. Drug Saf. 1997;17(2):75-92.

[2]. Mycophenolate mofetil. A review of its pharmacodynamic and pharmacokinetic properties and clinical efficacy in renal transplantation. Drugs. 1996;51(2):278-298.

[3]. Effect of the inosine 5'-monophosphate dehydrogenase inhibitor BMS-566419 on rat cardiac allograft rejection. Int Immunopharmacol, 2010. 10(1): p. 91-7.

[4]. Inhibition of microglial and astrocytic inflammatory responses by the immunosuppressant mycophenolate mofetil. Neuropathol Appl Neurobiol, 2010. 36(7): p. 598-611.

[5]. Mycophenolate mofetil and daclizumab targeting T lymphocytes in bleomycin-induced experimental scleroderma. Clin Exp Dermatol, 2012. 37(1): p. 48-54.

Mycophenolate mofetil is a carboxylic ester resulting from the formal condensation between the carboxylic acid group of mycophenolic acid and the hydroxy group of 2-(morpholin-4-yl)ethanol. In the liver, it is metabolised to mycophenolic acid, an immunosuppressant for which it is a prodrug. It is widely used to prevent tissue rejection following organ transplants as well as for the treatment of certain autoimmune diseases. It has a role as an immunosuppressive agent, a prodrug, an EC 1.1.1.205 (IMP dehydrogenase) inhibitor and an anticoronaviral agent. It is a gamma-lactone, a member of phenols, an ether, a carboxylic ester and a tertiary amino compound. It is functionally related to a mycophenolic acid and a 2-(morpholin-4-yl)ethanol.
Mycophenolate mofetil, also known as MMF or CellCept, is a prodrug of mycophenolic acid, and classified as a reversible inhibitor of inosine monophosphate dehydrogenase (IMPDH). This drug is an immunosuppressant combined with drugs such as [Cyclosporine] and corticosteroids to prevent organ rejection after hepatic, renal, and cardiac transplants. It is marketed by Roche Pharmaceuticals and was granted FDA approval for the prophylaxis of transplant rejection in 1995. In addition to the above uses, mycophenolate mofetil has also been studied for the treatment of nephritis and other complications of autoimmune diseases. Unlike another immunosuppressant class, the calcineurin inhibitors, MMF generally does not cause nephrotoxicity or fibrosis. Previously, mycophenolic acid (MPA) was administered to individuals with autoimmune diseases beginning in the 1970s, but was discontinued due to gastrointestinal effects and concerns over carcinogenicity. The new semi-synthetic 2-morpholinoethyl ester of MPA was synthesized to avoid the gastrointestinal effects associated with the administration of MPA. It demonstrates an increased bioavailability, a higher efficacy, and reduced gastrointestinal effects when compared to MPA.
Mycophenolate Mofetil is the morpholinoethyl ester of mycophenolic acid (MPA) with potent immunosuppressive properties. Mycophenolate stops T-cell and B-cell proliferation through selective inhibition of the de novo pathway of purine biosynthesis. In vivo, the active metabolite, MPA, reversibly inhibits inosine 5'-monophosphate dehydrogenase, an enzyme involved in the de novo synthesis of guanine nucleotides. MPA displays high lymphocyte specificity and cytotoxicity due to the higher dependence of activated lymphocytes on both salvage and de novo synthesis of guanine nucleotides relative to other cell types. (NCI04)
Compound derived from Penicillium stoloniferum and related species. It blocks de novo biosynthesis of purine nucleotides by inhibition of the enzyme inosine monophosphate dehydrogenase (IMP DEHYDROGENASE). Mycophenolic acid exerts selective effects on the immune system in which it prevents the proliferation of T-CELLS, LYMPHOCYTES, and the formation of antibodies from B-CELLS. It may also inhibit recruitment of LEUKOCYTES to sites of INFLAMMATION.
See also: Mycophenolic Acid (has active moiety); Mycophenolate Mofetil Hydrochloride (has salt form).

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Drug Indication
Mycophenolate mofetil is indicated in combination with other immunosuppressants to prevent the rejection of kidney, heart, or liver transplants in adult and pediatric patients ≥3 months old. Mycophenolate mofetil may also be used off-label as a second-line treatment for autoimmune hepatitis that has not responded adequately to first-line therapy. Other off-label uses of this drug include lupus-associated nephritis and dermatitis in children.
FDA Label
CellCept is indicated in combination with ciclosporin and corticosteroids for the prophylaxis of acute transplant rejection in patients receiving allogeneic renal, cardiac or hepatic transplants.
Myfenax is indicated in combination with ciclosporin and corticosteroids for the prophylaxis of acute transplant rejection in patients receiving allogeneic renal, cardiac or hepatic transplants.
Myclausen is indicated in combination with ciclosporin and corticosteroids for the prophylaxis of acute transplant rejection in patients receiving allogeneic renal, cardiac or hepatic transplants. ,
Mycophenolate mofetil Teva is indicated in combination with ciclosporin and corticosteroids for the prophylaxis of acute transplant rejection in patients receiving allogeneic renal, cardiac or hepatic transplants.

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Mechanism of Action
The active metabolite of mycophenolate, mycophenolic acid, prevents T-cell and B-cell proliferation and the production of cytotoxic T-cells and antibodies. Lymphocyte and monocyte adhesion to endothelial cells of blood vessels that normally part of inflammation is prevented via the glycosylation of cell adhesion molecules by MPA. MPA inhibits de novo purine biosynthesis (that promotes immune cell proliferation) by inhibiting inosine 5’-monophosphate dehydrogenase enzyme (IMPDH), with a preferential inhibition of IMPDH II. IMPDH normally transforms inosine monophosphate (IMP) to xanthine monophosphate (XMP), a metabolite contributing to the production of guanosine triphosphate (GTP). GTP is an important molecule for the synthesis of ribonucleic acid (RNA), deoxyribonucleic acid (DNA), and protein. As a result of the above cascade of effects, mycophenolate mofetil reduces de-novo production of guanosine nucleotides, interfering with the synthesis of DNA, RNA, and protein required for immune cell production. Further contributing to the above anti-inflammatory effects, MMF depletes tetrahydrobiopterin, causing the decreased function of inducible nitric oxide synthase enzyme, in turn decreasing the production of peroxynitrite, a molecule that promotes inflammation.
As a potent, selective, noncompetitive, and reversible, inhibitor of inosine monophosphate dehydrogenase (IMPDH), mycophenolic acid (MPA), the active metabolite /of mycophenolate mofetil/, inhibits the de novo synthesis pathway of guanosine nucleotides without being incorporated into DNA. Because T and B lymphocytes are critically dependent for their proliferation on de novo synthesis of purines, while other cell types can utilize salvage pathways, MPA has potent cytostatic effects on lymphocytes. MPA inhibit proliferative responses of T and B lymphocytes to both mitogenic and allospecific stimulation. The addition of guanosine or deoxyguanosine reverses the cytostatic effects of MPA on lymphocytes. MPA also suppresses antibody formation by B lymphocytes. MPA prevents the glycosylation of lymphocytes and monocyte glycoproteins that are involved in intercellular adhesion of these cells to endothelial cells, and may inhibit recruitment of leukocytes into sites of inflammation and graft rejection. Mycophenolate mofetil dose not inhibit the early events in the activation of human peripheral blood mononuclear cells, such as the production of interleukin-1 and interleukin-2, but does block the coupling of these events to DNA synthesis and proliferation.

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Mycophenolate mofetil (the morpholinoethyl ester of mycophenolic acid) inhibits de novo purine synthesis via the inhibition of inosine monophosphate dehydrogenase. Its selective lymphocyte antiproliferative effects involve both T and B cells, preventing antibody formation. Mycophenolate mofetil has immuno-suppressive effects alone, but is used most commonly in combination with other immunosuppressants. Mycophenolate mofetil, in combination with cyclosporin and corticosteroids, has been studied in large, randomised clinical trials involving nearly 1500 renal allograft transplant recipients. These trials demonstrated that mycophenolate mofetil is significantly more effective in reducing treatment failure and acute rejection episodes than placebo or azathioprine. Additionally, mycophenolate mofetil may be able to reduce the occurrence of chronic rejection. Mycophenolate mofetil is relatively well tolerated. The most common adverse effect reported is gastrointestinal intolerance; haematological aberrations have also been noted. The reversible cytostatic action of mycophenolate mofetil allows for dose adjustment or discontinuation, preventing serious toxicity or an overly suppressed immune system. Cytomegalovirus tissue invasive disease and the development of malignancies are concerns that merit evaluation in long term follow-up studies. Mycophenolate mofetil does not cause the adverse effects typically associated with other commercially available immunosuppressant medications such as nephrotoxicity, hepatotoxicity, hypertension, nervous system disturbances, electrolyte abnormalities, skin disorders, hyperglycaemia, hyperuricaemia, hypercholesterolaemia, lipid disorders and structural bone loss. Based on preliminary information, a positive benefit-risk ratio has been demonstrated with the use of mycophenolate mofetil in the prophylaxis of rejection in cadaveric renal allograft transplantation. Data from studies in other types of organ transplants are promising, but are too limited to draw clear conclusions. Long term follow-up studies are required to confirm these observations. Although mycophenolate mofetil is expensive, the beneficial effects on the reduction of rejection, treatment failure and related expenses suggest that it is most likely to be cost effective.[1]

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Compound derived from Penicillium stoloniferum and related species. It blocks de novo biosynthesis of purine nucleotides by inhibition of the enzyme inosine monophosphate dehydrogenase (IMP DEHYDROGENASE). Mycophenolic acid exerts selective effects on the immune system in which it prevents the proliferation of T-CELLS, LYMPHOCYTES, and the formation of antibodies from B-CELLS. It may also inhibit recruitment of LEUKOCYTES to sites of INFLAMMATION.
See also: Mycophenolic Acid (has active moiety); Mycophenolate Mofetil (is salt form of).

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In summary, our results indicate that MMF: (i) inhibits the secretion of TNF-α, IL-1β and NO of microglial cells; (ii) inhibits TNF-α secretion of astrocytes; (iii) suppresses the proliferation of microglial cells and astrocytes; (iv) has no direct neuroprotective effects on cultured, excitotoxically injured hippocampal neurones; and (v) acts by inhibiting glial IMPDH. Against a background of promising animal experiments and open label clinical trials on the use of MMF in various CNS disorders, MMF seems to be a promising candidate for further investigations on the treatment of acute brain and spinal cord pathologies.[4]

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MMF and DCZ, which target T lymphocytes, inhibit inflammatory activity, and thus prevent the development of skin fibrosis in early stages of a mouse model of BLM‐induced scleroderma. However, MMF is more effective at suppressing fibroblastic activation than in DCZ, and has a more prominent antifibrotic effect. These results support the assumption that T lymphocytes play an important role in the pathogenesis of scleroderma, and that suppression of T lymphocytes may be an effective strategy for treatment of human scleroderma, when started during the early stages of the disease. However, targeting T lymphocytes alone may not be an adequate treatment approach for scleroderma.[5]

C23H31NO7

433.4947

433.21

C, 63.73; H, 7.21; N, 3.23; O, 25.83

128794-94-5

Mycophenolate Mofetil-d4;1132748-21-0;Mycophenolate mofetil hydrochloride;116680-01-4

5281078

White to off-white solid powder

1.2±0.1 g/cm3

637.6±55.0 °C at 760 mmHg

95-96ºC

339.4±31.5 °C

0.0±2.0 mmHg at 25°C

1.557

3.15

1

8

10

31

646

0

O1C([H])([H])C([H])([H])N(C([H])([H])C([H])([H])OC(C([H])([H])C([H])([H])/C(/C([H])([H])[H])=C(\[H])/C([H])([H])C2C(=C3C(=O)OC([H])([H])C3=C(C([H])([H])[H])C=2OC([H])([H])[H])O[H])=O)C([H])([H])C1([H])[H]

RTGDFNSFWBGLEC-SYZQJQIISA-N

InChI=1S/C23H31NO7/c1-15(5-7-19(25)30-13-10-24-8-11-29-12-9-24)4-6-17-21(26)20-18(14-31-23(20)27)16(2)22(17)28-3/h4,26H,5-14H2,1-3H3/b15-4+

2-morpholin-4-ylethyl (E)-6-(4-hydroxy-6-methoxy-7-methyl-3-oxo-1H-2-benzofuran-5-yl)-4-methylhex-4-enoate

RS61443; Mycophenolic acid; mycophenolate mofetil; 128794-94-5; 115007-34-6; Myfenax; myclausen; Mycophenylate mofetil; Mycophenolic acid morpholinoethyl ester; Mycophenolate mofetil Teva; Mycophenolate mofetil, Cellcept, Myfortic, RS-61443;Mycophenolate mofetil (free acid);

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.5 mg/mL (5.77 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (5.77 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (5.77 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 0.5% methylcellulose:20 mg/mL

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Solubility in Formulation 5: 33.33 mg/mL (76.89 mM) in Cremophor EL (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.

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 (Please use freshly prepared in vivo formulations for optimal results.)