FKBP12; calcineurin; macrocyclic lactone

Activation of NO synthase, IL-2 gene transcription, cell degranulation, and apoptosis are among the calcium-dependent processes that are inhibited by tacrolimus monohydrate (FK506 monohydrate, Fujimycin monohydrate, FR900506 monohydrate). By binding to FKBPs inside the hormone receptor complex and inhibiting degradation, tacrolimus also increases the effects of progesterone and glucocorticoids. The drug might increase TGFβ-1 gene expression in a manner similar to what has been seen for CsA. Tacrolimus inhibits T cell growth in response to T cell receptor ligation[1]. The treatment of MH3924A cells with a low dosage of Tacrolimus (FK506, 10 μg/L) does not greatly impact their ability to proliferate (P=0.135). Treatment with increasing concentrations of Tacrolimus (100-1,000 μg/L) dramatically increases (P<0.01) the proliferation of MH3924A cells. AMD3100 treatment, at any dose (10, 50, or 100 μg/L), does not appear to affect the proliferation of MH3924A cells (P>0.05). However, the in vitro proliferation of MH3924A cells is boosted (P<0.01)[3] when different doses of AMD3100 are coupled with 100 μg/L Tacrolimus.

Mice treated with Dextran sulfate sodium (DSS) from Days 10 to 16 or 23 are given Tacrolimus to study the therapeutic effect on the progression and maintenance of colitis. In comparison to normal animals, the control group treated with DSS exhibited a substantial reduction in colon length and an increase in colon weight at Days 17 and 24. Furthermore, the control group's colon weight per unit length is more than twice as high as the normal group's. While Tacrolimus treatment for 7 or 14 days considerably suppresses increases in colon weight per unit length in rats treated with DSS as compared to the control group, the colon shortening is not actually restored by this treatment. Furthermore, as indicated by the inhibitory percentages (59% vs. 28%), the inhibitory effect of tacrolimus on increases in colon weight per unit length is more pronounced with a 14-d treatment than a 7-d treatment[4].

Tacrolimus (FK506) inhibits calcium-dependent events, such as IL-2 gene transcription, NO synthase activation, cell degranulation, and apoptosis. Tacrolimus also potentiates the actions of glucocorticoids and progesterone by binding to FKBPs contained within the hormone receptor complex, preventing degradation. The agent may enhance expression of the TGFβ-1 gene in a fashion analogous to that demonstrated for CsA. T cell proliferation in response to ligation of the T cell receptor is inhibited by Tacrolimus. Treatment with a low concentration of Tacrolimus (FK506,10 μg/L) does not significantly affect the proliferation of MH3924A cells (P=0.135). Upon treatment with higher concentrations of Tacrolimus (100-1,000 μg/L), the proliferation of MH3924A cells is significantly enhanced (P<0.01). However, when different concentrations of AMD3100 are combined with 100 μg/L Tacrolimus, the in vitro proliferation of MH3924A cells is increased (P<0.01).

Tacrolimus, formerly known as FK506, is a macrolide antibiotic with immunosuppressive properties. Although structurally unrelated to cyclosporin A (CsA), its mode of action is similar. It exerts its effects principally through impairment of gene expression in target cells. Tacrolimus bonds to an immunophilin, FK506 binding protein (FKBP). This complex inhibits calcineurin phosphatase. The drug inhibits calcium-dependent events, such as interleukin-2 gene transcription, nitric oxide synthase activation, cell degranulation, and apoptosis. Tacrolimus also potentiates the actions of glucocorticoids and progesterone by binding to FKBPs contained within the hormone receptor complex, preventing degradation. The agent may enhance expression of the transforming growth factor beta-1 gene in a fashion analogous to that demonstrated for CsA. T cell proliferation in response to ligation of the T cell receptor is inhibited by tacrolimus. Type 1 T helper cells appear to be preferentially suppressed compared with type 2 T helper cells. T cell-mediated cytotoxicity is impaired. B cell growth and antibody production are affected indirectly by the suppression of T cell-derived growth factors necessary for these functions. Antigen presentation appears to be spared. The molecular events affected by tacrolimus continue to be discovered[1].

Absorption, Distribution and Excretion
Absorption of tacrolimus from the gastrointestinal tract after oral administration is incomplete and variable. The absolute bioavailability in adult kidney transplant patients is 17±10%; in adults liver transplant patients is 22±6%; in healthy subjects is 18±5%. The absolute bioavailability in pediatric liver transplant patients was 31±24%. Tacrolimus maximum blood concentrations (Cmax) and area under the curve (AUC) appeared to increase in a dose-proportional fashion in 18 fasted healthy volunteers receiving a single oral dose of 3, 7, and 10 mg. When given without food, the rate and extent of absorption were the greatest. The time of the meal also affected bioavailability. When given immediately after a meal, mean Cmax was reduced 71%, and mean AUC was reduced 39%, relative to the fasted condition. When administered 1.5 hours following the meal, mean Cmax was reduced 63%, and mean AUC was reduced 39%, relative to the fasted condition.
In man, less than 1% of the dose administered is excreted unchanged in urine. When administered IV, fecal elimination accounted for 92.6±30.7%, urinary elimination accounted for 2.3±1.1%.
2.6 ± 2.1 L/kg [pediatric liver transplant patients]
1.07 ± 0.20 L/kg [patients with renal impairment, 0.02 mg/kg/4 hr dose, IV]
3.1 ± 1.6 L/kg [Mild Hepatic Impairment, 0.02 mg/kg/4 hr dose, IV]
3.7 ± 4.7 L/kg [Mild Hepatic Impairment, 7.7 mg dose, PO]
3.9 ± 1.0 L/kg [Severe hepatic impairment, 0.02 mg/kg/4 hr dose, IV]
3.1 ± 3.4 L/kg [Severe hepatic impairment, 8 mg dose, PO]
0.040 L/hr/kg [healthy subjects, IV]
0.172 ± 0.088 L/hr/kg [healthy subjects, oral]
0.083 L/hr/kg [adult kidney transplant patients, IV]
0.053 L/hr/kg [adult liver transplant patients, IV]
0.051 L/hr/kg [adult heart transplant patients, IV]
0.138 ± 0.071 L/hr/kg [pediatric liver transplant patients]
0.12 ± 0.04 (range 0.06-0.17) L/hr/kg [pediatric kidney transplant patients]
0.038 ± 0.014 L/hr/kg [patients with renal impairment, 0.02 mg/kg/4 hr dose, IV]
0.042 ± 0.02 L/hr/kg [Mild Hepatic Impairment, 0.02 mg/kg/4 hr dose, IV]
0.034 ± 0.019 L/hr/kg [Mild Hepatic Impairment, 7.7 mg dose, PO]
0.017 ± 0.013 L/hr/kg [Severe hepatic impairment, 0.02 mg/kg/4 hr dose, IV]
0.016 ± 0.011 L/hr/kg [Severe hepatic impairment, 8 mg dose, PO]
The aim of this study was to assess tacrolimus levels in breast milk and neonatal exposure during breastfeeding. An observational cohort study was performed in two tertiary referral high-risk obstetric medicine clinics. Fourteen women taking tacrolimus during pregnancy and lactation, and their 15 infants, 11 of whom were exclusively breast-fed, were assessed. Tacrolimus levels were analyzed by liquid chromatography-tandem mass spectrometry. Samples from mothers and cord blood were collected at delivery and from mothers, infants, and breast milk postnatally where possible. All infants with serial sampling had a decline in tacrolimus level, which was approximately 15% per day (ratio of geometric mean concentrations 0.85; 95% confidence interval, 0.82-0.88; P<0.001). Breast-fed infants did not have higher tacrolimus levels compared with bottle-fed infants (median 1.3 ug/L [range, 0.0-4.0] versus 1.0 ug/L (range, 0.0-2.3), respectively; P=0.91). Maximum estimated absorption from breast milk is 0.23% of maternal dose (weight-adjusted). Ingestion of tacrolimus by infants via breast milk is negligible. Breastfeeding does not appear to slow the decline of infant tacrolimus levels from higher levels present at birth.
Maternal and umbilical cord (venous and arterial) samples were obtained at delivery from eight solid organ allograft recipients to measure tacrolimus and metabolite bound and unbound concentrations in blood and plasma. Tacrolimus pharmacokinetics in breast milk were assessed in one subject. Mean (+ or - SD) tacrolimus concentrations at the time of delivery in umbilical cord venous blood (6.6 + or - 1.8 ng ml(-1)) were 71 + or - 18% (range 45-99%) of maternal concentrations (9.0 + or - 3.4 ng ml(-1)). The mean umbilical cord venous plasma (0.09 + or - 0.04 ng ml(-1)) and unbound drug concentrations (0.003 + or - 0.001 ng ml(-1)) were approximately one fifth of the respective maternal concentrations. Arterial umbilical cord blood concentrations of tacrolimus were 100 + or - 12% of umbilical venous concentrations. In addition, infant exposure to tacrolimus through the breast milk was less than 0.3% of the mother's weight-adjusted dose. Differences between maternal and umbilical cord tacrolimus concentrations may be explained in part by placental P-gp function, greater red blood cell partitioning and higher haematocrit levels in venous cord blood.
Ten colostrum samples were obtained from six women in the immediate postpartum period (0-3 days) with a mean drug concentration of 0.79 ng/mL (range 0.3-1.9 ng/mL). The median milk:maternal plasma ratio was 0.5.
The plasma protein binding of tacrolimus is approximately 99% and is independent of concentration over a range of 5-50 ng/mL. Tacrolimus is bound mainly to albumin and alpha-1-acid glycoprotein, and has a high level of association with erythrocytes. The distribution of tacrolimus between whole blood and plasma depends on several factors, such as hematocrit, temperature at the time of plasma separation, drug concentration, and plasma protein concentration. In a US study, the ratio of whole blood concentration to plasma concentration averaged 35 (range 12 to 67). There was no evidence based on blood concentrations that tacrolimus accumulates systemically upon intermittent topical application for periods of up to 1 year. As with other topical calcineurin inhibitors, it is not known whether tacrolimus is distributed into the lymphatic system.
For more Absorption, Distribution and Excretion (Complete) data for Tacrolimus (9 total), please visit the HSDB record page.

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Metabolism / Metabolites
The metabolism of tacrolimus is predominantly mediated by CYP3A4 and secondarily by CYP3A5. Tacrolimus is metabolized into 8 metabolites: 13-demethyl tacrolimus, 31-demethyl tacrolimus, 15-demethyl tacrolimus, 12-hydroxy tacrolimus, 15,31-didemethyl tacrolimus, 13,31-didemethyl tacrolimus, 13,15-didemethyl tacrolimus, and a final metabolite involving O-demethylation and the formation of a fused ring. The major metabolite identified in incubations with human liver microsomes is 13-demethyl tacrolimus. In in vitro studies, a 31-demethyl metabolite has been reported to have the same activity as tacrolimus.
Tacrolimus is extensively metabolized by the mixed-function oxidase system, primarily the cytochrome P-450 system (CYP3A). A metabolic pathway leading to the formation of 8 possible metabolites has been proposed. Demethylation and hydroxylation were identified as the primary mechanisms of biotransformation in vitro. The major metabolite identified in incubations with human liver microsomes is 13-demethyl tacrolimus. In in vitro studies, a 31-demethyl metabolite has been reported to have the same activity as tacrolimus.
Fk_506 has known human metabolites that include 13-O-Desmethyltacrolimus and 15-O-Desmethyltacrolimus.

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Biological Half-Life
The elimination half life in adult healthy volunteers, kidney transplant patients, liver transplants patients, and heart transplant patients are approximately 35, 19, 12, 24 hours, respectively. The elimination half life in pediatric liver transplant patients was 11.5±3.8 hours, in pediatric kidney transplant patients was 10.2±5.0 (range 3.4-25) hours.
In a mass balance study of IV administered radiolabeled tacrolimus to 6 healthy volunteers, ... the elimination half-life based on radioactivity was 48.1+ or - 15.9 hours whereas it was 43.5 + or- 11.6 hours based on tacrolimus concentrations. ... When administered PO, the elimination half-life based on radioactivity was 31.9 + or- 10.5 hours whereas it was 48.4 + or - 12.3 hours based on tacrolimus concentrations ... .
... A case of tacrolimus toxicity in a non-transplant patient /is presented/. ... /The/ patient's tacrolimus dose was 2.1 mg/kg/day for 4 days (therapeutic 0.03 to 0.05 mg/kg/day). Her tacrolimus elimination half-life was 16.5 hours, compared to a mean half-life in healthy volunteers of 34.2 +/- 7.7 hours. ...

Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Limited data indicate that amounts of systemically administered tacrolimus are low in breastmilk and probably do not adversely affect the breastfed infant. United States and European experts and guidelines consider tacrolimus to be probably safe to use during breastfeeding. Exclusively breastfed infants should be monitored if this drug is used during lactation, possibly including measurement of serum levels to rule out toxicity if there is a concern.
Topical tacrolimus presents a low risk to the nursing infant because it is poorly absorbed after topical application and peak blood concentrations are less than 2 mcg/L in most patients. Ensure that the infant's skin does not come into direct contact with the areas of skin that have been treated. Current guidelines allow topical tacrolimus to be applied to the nipples just after nursing, with the nipples cleaned gently before nursing. Only water-miscible cream or gel products should be applied to the breast or nipple because ointments may expose the infant to high levels of mineral paraffins via licking, so pimecrolimus cream may be preferable to tacrolimus ointment for nipple application.
◉ Effects in Breastfed Infants
One infant was exclusively breastfed during maternal tacrolimus therapy throughout gestation to at least 2.5 months of age at which time the infant was developing normally physically and neurologically. An ultrasound examination of the infant's thymus was normal.
The National Transplantation Pregnancy Registry reported data gathered from 1991 to 2011 on mothers who breastfed their infants following organ transplantation. A total of 68 mothers with transplants (mostly kidney or liver) used tacrolimus while breastfeeding a total of 83 infants. Duration of nursing ranged from 1 week to 1.5 years and follow-up of the children ranged from weeks to 16 years. There were no reports of problems in any of the infants or children. As of December 2013, a total of 92 mothers had breastfed 125 infants for as long as 26 months with no apparent adverse effects in infants.
The breastfed infants of six women who took tacrolimus during pregnancy for organ transplantation were breastfed (4 exclusive, 2 partial) for 45 to 180 days and followed for periods of 2 to 30 months. The mothers' mean daily tacrolimus dosage during breastfeeding was 9.6 mg daily (range 4.5 to 15 mg daily). Four mothers were also taking azathioprine 100 to 150 mg daily, one was taking diltiazem, and one was taking prednisolone 15 mg and aspirin 75 mg daily. None of the infants had any clear tacrolimus-related side effects, although one had transient thrombocytosis that resolved despite continued breastfeeding. Developmental milestones were normal and no pattern of infections was noted.
Two mothers with systemic lupus erythematosus were reported who took tacrolimus 3 mg daily during pregnancy and lactation as well as prednisolone 30 or 40 mg daily. Three years after birth, both children were healthy. The durations of lactation were not stated.
In a case series of women who had liver transplants over a 25-year period, one woman breastfed (extent not stated) her infant while taking tacrolimus. No neonatal complications were noted.
A mother with a liver transplant was maintained on belatacept 10 mg/kg monthly, slow-release tacrolimus (Envarsus and Veloxis) 2 mg daily, azathioprine 25 mg daily, and prednisone 2.5 mg daily. She breastfed her infant for a year (extent not stated). The infant’s growth and cognitive milestones were normal.
An Australian case series reported 3 women with heart transplants who had a total of 5 infants, all of whom were breastfed (extent not stated) during maternal tacrolimus therapy. Daily dosages ranged from 3 to 13 mg daily. No adverse infant effects were reported up to the times of discharge.
A woman with rheumatoid arthritis refractory to etanercept took sarilumab 200 mg every two weeks during pregnancy until 37 weeks of gestation. She was also taking prednisolone 10 mg and tacrolimus 3 mg daily. She delivered a healthy infant at 38 weeks of gestation and breastfed her infant. Prednisolone was continued postpartum, tacrolimus was restarted at 7 days postpartum, and sarilumab was restarted at 28 days postpartum. The mother continued to breastfeed until 6 months postpartum. The infant was vaccinated with multiple live vaccines after reaching six months old, including the Bacille-Calmette-Guerin vaccine, with no adverse effects.
A woman with a heart transplant took tacrolimus alone throughout pregnancy and postpartum while breastfeeding her infant (extent not stated) for one year. The child had normal weight gain, normal motor development, and no signs of metabolic disorders or significant infections. The age of the infant at evaluation was not stated.
◉ Effects on Lactation and Breastmilk
A study in renal transplant patients who were on a tacrolimus-based immunosuppression regimen found that women’s median serum prolactin levels were 14.4 mcg/L compared with women who were not taking tacrolimus (17.6 mcg/L). The difference was statistically significant. Median serum testosterone levels (0.121 vs 0.137 mcg/L) and serum cortisol levels (82.5 vs 105 mg/L) were also significantly lower in the tacrolimus group. The reduced prolactin may be caused by inhibition of the transcription of the human prolactin gene. Not all studies have found a reduction in serum prolactin with tacrolimus. The prolactin level in a mother with established lactation may not affect her ability to breastfeed.

[1]. Mode of action of Tacrolimus (FK506): molecular and cellular mechanisms. Ther Drug Monit. 1995 Dec;17(6):584-91.

[2]. Tacrolimus ameliorates dextran sulfate sodium-induced colitis in mice: implication of interferon-γ and interleukin-1β suppression. Biol Pharm Bull. 2011;34(12):1823-7.

[3]. mTOR inhibitors rescue premature lethality and attenuate dysregulation of GABAergic/glutamatergic transcription in murine succinate semialdehyde dehydrogenase deficiency (SSADHD), a disorder of GABA metabolism. J Inherit Metab Dis. 2016 Nov;39(6):877-886.

[4]. Tacrolimus promotes hepatocellular carcinoma and enhances CXCR4/SDF 1α expression in vivo. Mol Med Rep. 2014 Aug;10(2):585-92.

Tacrolimus hydrate is a hydrate that is the monohydrate form of tacrolimus. It has a role as an immunosuppressive agent. It contains a tacrolimus (anhydrous).
A macrolide isolated from the culture broth of a strain of Streptomyces tsukubaensis that has strong immunosuppressive activity in vivo and prevents the activation of T-lymphocytes in response to antigenic or mitogenic stimulation in vitro.
See also: Tacrolimus (annotation moved to). Therapeutic Uses
Immunosuppressive Agents
Prograf is indicated for the prophylaxis of organ rejection in patients receiving allogeneic kidney transplants. It is recommended that Prograf be used concomitantly with azathioprine or mycophenolate mofetil (MMF) and adrenal corticosteroids. /Included in US product label/
Prograf is indicated for the prophylaxis of organ rejection in patients receiving allogeneic liver transplants. It is recommended that Prograf be used concomitantly with adrenal corticosteroids. Therapeutic drug monitoring is recommended for all patients receiving Prograf. /Included in US product label/
Prograf is indicated for the prophylaxis of organ rejection in patients receiving allogeneic heart transplants. It is recommended that Prograf be used concomitantly with azathioprine or mycophenolate mofetil (MMF) and adrenal corticosteroids. /Included in US product label/
For more Therapeutic Uses (Complete) data for Tacrolimus (13 total), please visit the HSDB record page.

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Drug Warnings
/BOXED WARNING/ MALIGNANCIES AND SERIOUS INFECTIONS. Increased risk of development of lymphoma and other malignancies, particularly of the skin, due to immunosuppression. Increased susceptibility to bacterial, viral, fungal, and protozoal infections, including opportunistic infections. Only physicians experienced in immunosuppressive therapy and management of organ transplant patients should prescribe Prograf. Patients receiving the drug should be managed in facilities equipped and staffed with adequate laboratory and supportive medical resources. The physician responsible for maintenance therapy should have complete information requisite for the follow-up of the patient.
/BOXED WARNING/ WARNING: Long-term Safety of Topical Calcineurin Inhibitors Has Not Been Established Although a causal relationship has not been established, rare cases of malignancy (e.g., skin and lymphoma) have been reported in patients treated with topical calcineurin inhibitors, including Protopic Ointment. Therefore: Continuous long-term use of topical calcineurin inhibitors, including Protopic Ointment, in any age group should be avoided, and application limited to areas of involvement with atopic dermatitis; Protopic Ointment is not indicated for use in children less than 2 years of age; Only 0.03% Protopic Ointment is indicated for use in children 2-15 years of age.
Topical tacrolimus therapy should be avoided for malignant or premalignant skin conditions (e.g., cutaneous T-cell lymphoma (CTCL)), which may appear clinically similar to dermatitis.
Because of a potential increased risk for skin cancer, patients /using topical tacrolimus/ should be advised to limit exposure to sunlight or other UV light by wearing protective clothing and using a broad-spectrum sunscreen with a high protection factor.
For more Drug Warnings (Complete) data for Tacrolimus (42 total), please visit the HSDB record page.

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Pharmacodynamics
Tacrolimus acts by reducing peptidyl-prolyl isomerase activity by binding to the immunophilin FKBP-12 (FK506 binding protein) creating a new complex. This inhibits both T-lymphocyte signal transduction and IL-2 transcription. Tacrolimus has similar activity to cyclosporine but rates of rejection are lower with tacrolimus. Tacrolimus has also been shown to be effective in the topical treatment of eczema, particularly atopic eczema. It suppresses inflammation in a similar way to steroids, but is not as powerful. An important dermatological advantage of tacrolimus is that it can be used directly on the face; topical steroids cannot be used on the face, as they thin the skin dramatically there. On other parts of the body, topical steroid are generally a better treatment.

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Cyclosporin A and FK506 inhibit T- and B-cell activation and other processes essential to an effective immune response. In T lymphocytes these drugs disrupt an unknown step in the transmission of signals from the T-cell antigen receptor to cytokine genes that coordinate the immune response. The putative intracellular receptors for FK506 and cyclosporin are cis-trans prolyl isomerases. Binding of the drug inhibits isomerase activity, but studies with other prolyl isomerase inhibitors and analysis of cyclosporin-resistant mutants in yeast suggest that the effects of the drug result from the formation of an inhibitory complex between the drug and isomerase, and not from inhibition of isomerase activity. A transcription factor, NF-AT, which is essential for early T-cell gene activation, seems to be a specific target of cyclosporin A and FK506 action because transcription directed by this protein is blocked in T cells treated with these drugs, with little or no effect on other transcription factors such as AP-1 and NF-kappa B. Here we demonstrate that NF-AT is formed when a signal from the antigen receptor induces a pre-existing cytoplasmic subunit to translocate to the nucleus and combine with a newly synthesized nuclear subunit of NF-AT. FK506 and cyclosporin A block translocation of the cytoplasmic component without affecting synthesis of the nuclear subunit. [1]

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Antigen recognition by the T-cell receptor (TCR) initiates events including lymphokine gene transcription, particularly interleukin-2, that lead to T-cell activation. The immunosuppressive drugs, cyclosporin A (CsA) and FK-506, prevent T-cell proliferation by inhibiting a Ca(2+)-dependent event required for induction of interleukin-2 transcription. Complexes of FK-506 or CsA and their respective intracellular binding proteins inhibit the calmodulin-dependent protein phosphatase, calcineurin, in vitro. The pharmacological relevance of this observation to immunosuppression or drug toxicity is undetermined. Calcineurin, although present in lymphocytes, has not been implicated in TCR-mediated activation of lymphokine genes or in transcriptional regulation in general. Here we report that transfection of a calcineurin catalytic subunit increases the 50% inhibitory concentration (IC50) of the immunosuppressants FK-506 and CsA, and that a mutant subunit acts in synergy with phorbol ester alone to activate the interleukin-2 promoter in a drug-sensitive manner. These results implicate calcineurin as a component of the TCR signal transduction pathway by demonstrating its role in the drug-sensitive activation of the interleukin-2 promoter.[2]

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The immunosuppressive agents cyclosporin A (CsA) and FK 506 bind to distinct families of intracellular proteins (immunophilins) termed cyclophilins and FK 506-binding proteins (FKBPs). Recently, it has been shown that, in vitro, the complexes of CsA-cyclophilin and FK 506-FKBP-12 bind to and inhibit the activity of calcineurin, a calcium-dependent serine/threonine phosphatase. We have investigated the effects of drug treatment on phosphatase activity in T lymphocytes. Calcineurin is expressed in T cells, and its activity can be measured in cell lysates. Both CsA and FK 506 specifically inhibit cellular calcineurin at drug concentrations that inhibit interleukin 2 production in activated T cells. Rapamycin, which binds to FKBPs but exhibits different biological activities than FK 506, has no effect on calcineurin activity. Furthermore, excess concentrations of rapamycin prevent the effects of FK 506, apparently by displacing FK 506 from FKBPs. These results show that calcineurin is a target of drug-immunophilin complexes in vivo and establish a physiological role for calcineurin in T-cell activation.[3]

C44H71NO13

822.05

821.492

C, 64.29; H, 8.71; N, 1.70; O, 25.30

109581-93-3

Tacrolimus;104987-11-3

5282315

White to off-white solid powder

871.7ºC at 760 mmHg

127-129°

481ºC

1.73E-35mmHg at 25°C

fungus Streptomyces tsukubaensis.

4.512

4

13

7

58

1480

14

O1[C@]2(C(C(N3C([H])([H])C([H])([H])C([H])([H])C([H])([H])[C@@]3([H])C(=O)O[C@]([H])(/C(/C([H])([H])[H])=C(\[H])/[C@]3([H])C([H])([H])C([H])([H])[C@]([H])([C@@]([H])(C3([H])[H])OC([H])([H])[H])O[H])[C@]([H])(C([H])([H])[H])[C@]([H])(C([H])([H])C([C@]([H])(C([H])([H])C([H])=C([H])[H])C([H])=C(C([H])([H])[H])C([H])([H])[C@]([H])(C([H])([H])[H])C([H])([H])[C@@]([H])([C@]1([H])[C@]([H])(C([H])([H])[C@@]2([H])C([H])([H])[H])OC([H])([H])[H])OC([H])([H])[H])=O)O[H])=O)=O)O[H].O([H])[H] |c:78|

NWJQLQGQZSIBAF-MLAUYUEBSA-N

InChI=1S/C44H69NO12.H2O/c1-10-13-31-19-25(2)18-26(3)20-37(54-8)40-38(55-9)22-28(5)44(52,57-40)41(49)42(50)45-17-12-11-14-32(45)43(51)56-39(29(6)34(47)24-35(31)48)27(4)21-30-15-16-33(46)36(23-30)53-7;/h10,19,21,26,28-34,36-40,46-47,52H,1,11-18,20,22-24H2,2-9H3;1H2/b25-19+,27-21+;/t26-,28+,29+,30-,31+,32-,33+,34-,36+,37-,38-,39+,40+,44+;/m0./s1

(1R,9S,12S,13R,14S,17R,18E,21S,23S,24R,25S,27R)-1,14-dihydroxy-12-[(E)-1-[(1R,3R,4R)-4-hydroxy-3-methoxycyclohexyl]prop-1-en-2-yl]-23,25-dimethoxy-13,19,21,27-tetramethyl-17-prop-2-enyl-11,28-dioxa-4-azatricyclo[22.3.1.04,9]octacos-18-ene-2,3,10,16-tetrone;hydrate

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: This product requires protection from light (avoid light exposure) during transportation and storage.

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 (3.04 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 (3.04 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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 (Please use freshly prepared in vivo formulations for optimal results.)