Prelamin-F

Uses

Chromium is an ingredient found in a variety of supplements and vitamins.

Indicated for use as a supplement to intravenous solutions given for total parenteral nutrition (TPN), to maintain chromium serum levels and to prevent depletion of endogenous stores and subsequent deficiency symptoms .

Copper is a transition metal found in a variety of supplements and vitamins, including intravenous solutions for total parenteral nutrition (TPN).

For use in the supplementation of total parenteral nutrition and in contraception with intrauterine devices .

Prophylaxis of megaloblastic anaemia in pregnancy, Supplement for women of child-bearing potential, Folate-deficient megaloblastic anaemia, Prophylaxis of neural tube defect in pregnancy

Effective for:

• Vitamin A deficiency. Taking vitamin A by mouth is effective for preventing and treating symptoms of vitamin A deficiency. Vitamin A deficiency can occur in people with protein deficiency, diabetes, over-active thyroid, fever, liver disease, cystic fibrosis, or an inherited disorder called abetalipoproteinemia.

Possibly Effective for:

• Breast cancer. Premenopausal women with a family history of breast cancer who consume high levels of vitamin A in their diet seem to have reduced risk of developing breast cancer. It is not known if taking vitamin A supplements has the same benefit.
• Cataracts. Research suggests that high intake of vitamin A in the diet is linked to a lower risk of developing cataracts.
• Diarrhea related to HIV. Taking vitamin A along with conventional medicines seems to decrease the risk of death from diarrhea in HIV-positive children with vitamin A deficiency.
• Malaria. Taking vitamin A by mouth seems to decrease malaria symptoms in children less than 3 years-old living in areas where malaria is common.
• Measles. Taking vitamin A by mouth seems to reduce the risk of measles complications or death in children with measles and vitamin A deficiency.
• Precancerous lesions in the mouth (oral leukoplakia). Research suggests that taking vitamin A can help treat precancerous lesions in the mouth.
• Recovery from laser eye surgery (photoreactive keratectomy). Taking vitamin A by mouth along with vitamin E seems to improve healing after laser eye surgery.
• Complications after pregnancy. Taking vitamin A seems to reduce the risk of diarrhea and fever after pregnancy in malnourished women.
• Complications during pregnancy. Taking vitamin A by mouth seems to reduce the risk of death and night blindness during pregnancy in malnourished women.
• Eye disease affecting the retina (retinitis pigmentosa). Research suggests that taking vitamin A can slow the progression of an eye disease that causes damage to the retina.

Vitamin D is an ingredient found in a variety of supplements and vitamins.

Vitamin D is indicated for use in the treatment of hypoparathyroidism, refractory rickets (also known as vitamin D resistant rickets), and familial hypophosphatemia .

Zinc is an essential element commonly used for the treatment of patients with documented zinc deficiency.

Zinc can be used for the treatment and prevention of zinc deficiency/its consequences, including stunted growth and acute diarrhea in children, and slowed wound healing. It is also utilized for boosting the immune system, treating the common cold and recurrent ear infections, as well as preventing lower respiratory tract infections .

Prelamin-F is also used to associated treatment for these conditions: Mineral supplementationEmergency Contraception, IUD, Trace Element Deficiency, Dietary supplementationAnaemia folate deficiency, Folate deficiency, Iron Deficiency (ID), Iron Deficiency Anemia (IDA), Latent Iron Deficiency, Neural Tube Defects (NTDs), Vitamin Deficiency, Methotrexate toxicity, Nutritional supplementationDeficiency, Vitamin A, Deficiency, Vitamin D, Degenerative Retinal Disorders, Disorder of the Epithelium, Disorder of the Mesoderm, Inner ear disorder, Vitamin Deficiency, Vitamin E Deficiency, Nutritional supplementationDeficiency, Vitamin DCandidiasis, Common Cold, Diaper Dermatitis, Diaper Rash, Eye redness, Iron Deficiency (ID), Ocular Irritation, Skin Irritation, Sunburn, Wilson's Disease, Zinc Deficiency, Dietary and Nutritional Therapies, Dietary supplementation

How Prelamin-F works

Chromium is an essential nutrient involved in the metabolism of glucose, insulin and blood lipids. Its role in potentiating insulin signalling cascades has been implicated in several studies. Chromium upregulates insulin-stimulated insulin signal transduction via affecting effector molecules downstream of the insulin receptor (IR). IR-mediated signalling pathway involves phoshorylation of multiple intracellular domains and protein kinases, and downstream effector molecules . Upon activation by ligands, intracellular β-subunit of IR autophosphorylates and activates tyrosine kinase domain of the IR, followed by activation and phosphorylation of regulatory proteins and downstream signalling effectors including phosphatidylinositol 2-kinase (PI3K). PI3K activates further downstream reaction cascades to activate protein kinase B (Akt) to ultimately promote translocation of glucose transporter-4 (Glut4)-vesicles from the cytoplasm to the cell surface and regulate glucose uptake . Chromium enhances the kinase activity of insulin receptor β and increases the activity of downstream effectors, pI3-kinase and Akt.

Under insulin-resistant conditions, chromium also promotes GLUT-4 transporter translocation that is independent of activity of IR, IRS-1, PI3-kinase, or Akt; chromium mediates cholesterol efflux from the membranes via increasing fluidity of the membrane by decreasing the membrane cholesterol and upregulation of sterol regulatory element-binding protein . As a result, intracellular GLUT-4 transporters are stimulated to translocate from intracellular to the plasma membrane, leading to enhanced glucose uptake in muscle cells . Chromium attenuates the activity of PTP-1B in vitro, which is a negative regulator of insulin signaling. It also alleviates ER stress that is observed to be elevated the suppression of insulin signaling. ER stress is thought to activate c-Jun N-terminal kinase (JNK), which subsequently induces serine phosphorylation of IRS and aberration of insulin signalling . Transient upregulation of AMPK by chromium also leads to increased glucose uptake .

Copper is absorbed from the gut via high affinity copper uptake protein and likely through low affinity copper uptake protein and natural resistance-associated macrophage protein-2 . It is believed that copper is reduced to the Cu1+ form prior to transport. Once inside the enterocyte, it is bound to copper transport protein ATOX1 which shuttles the ion to copper transporting ATPase-1 on the golgi membrane which take up copper into the golgi apparatus. Once copper has been secreted by enterocytes into the systemic circulation it remain largely bound by ceruloplasmin (65-90%), albumin (18%), and alpha 2-macroglobulin (12%).

Copper is an essential element in the body and is incorporated into many oxidase enzymes as a cofactor . It is also a component of zinc/copper super oxide dismutase, giving it an anti-oxidant role. Copper defiency occurs in Occipital Horn Syndrome and Menke's disease both of which are associated with impaired development of connective tissue due to the lack of copper to act as a cofactor in protein-lysine-6-oxidase. Menke's disease is also associated with progressive neurological impairment leading to death in infancy. The precise mechanisms of the effects of copper deficiency are vague due to the wide range of enzymes which use the ion as a cofactor.

Copper appears to reduce the viabilty and motility of spermatozoa . This reduces the likelihood of fertilization with a copper IUD, producing copper's contraceptive effect . The exact mechanism of copper's effect on sperm are unknown.

Folic acid, as it is biochemically inactive, is converted to tetrahydrofolic acid and methyltetrahydrofolate by dihydrofolate reductase (DHFR). These folic acid congeners are transported across cells by receptor-mediated endocytosis where they are needed to maintain normal erythropoiesis, synthesize purine and thymidylate nucleic acids, interconvert amino acids, methylate tRNA, and generate and use formate. Using vitamin B12 as a cofactor, folic acid can normalize high homocysteine levels by remethylation of homocysteine to methionine via methionine synthetase.

Vision:Vitamin A (all-trans retinol) is converted in the retina to the 11-cis-isomer of retinaldehyde or 11-cis-retinal. 11-cis-retinal functions in the retina in the transduction of light into the neural signals necessary for vision. 11-cis-retinal, while attached to opsin in rhodopsin is isomerized to all-trans-retinal by light. This is the event that triggers the nerve impulse to the brain which allows for the perception of light. All-trans-retinal is then released from opsin and reduced to all-trans-retinol. All-trans-retinol is isomerized to 11-cis-retinol in the dark, and then oxidized to 11-cis-retinal. 11-cis-retinal recombines with opsin to re-form rhodopsin. Night blindness or defective vision at low illumination results from a failure to re-synthesize 11-cis retinal rapidly.
Epithelial differentiation: The role of Vitamin A in epithelial differentiation, as well as in other physiological processes, involves the binding of Vitamin A to two families of nuclear retinoid receptors (retinoic acid receptors, RARs; and retinoid-X receptors, RXRs). These receptors function as ligand-activated transcription factors that modulate gene transcription. When there is not enough Vitamin A to bind these receptors, natural cell differentiation and growth are interrupted.

Most individuals naturally generate adequate amounts of vitamin D through ordinary dietary intake of vitamin D (in some foods like eggs, fish, and cheese) and natural photochemical conversion of the vitamin D3 precursor 7-dehydrocholesterol in the skin via exposure to sunlight.

Conversely, vitamin D deficiency can often occur from a combination of insufficient exposure to sunlight, inadequate dietary intake of vitamin D, genetic defects with endogenous vitamin D receptor, or even severe liver or kidney disease . Such deficiency is known for resulting in conditions like rickets or osteomalacia, all of which reflect inadequate mineralization of bone, enhanced compensatory skeletal demineralization, resultant decreased calcium ion blood concentrations, and increases in the production and secretion of parathyroid hormone . Increases in parathyroid hormone stimulates the mobilization of skeletal calcium and the renal excretion of phosphorus . This enhanced mobilization of skeletal calcium leads towards porotic bone conditions .

Ordinarily, while vitamin D3 is made naturally via photochemical processes in the skin, both itself and vitamin D2 can be found in various food and pharmaceutical sources as dietary supplements. The principal biological function of vitamin D is the maintenance of normal levels of serum calcium and phosphorus in the bloodstream by enhancing the efficacy of the small intestine to absorb these minerals from the diet . At the liver, vitamin D3 or D2 is hydroxylated to 25-hydroxyvitamin D and then finally to the primary active metabolite 1,25-dihydroxyvitamin D in the kidney via further hydroxylation . This final metabolite binds to endogenous vitamin d receptors, which results in a variety of regulatory roles - including maintaining calcium balance, the regulation of parathyroid hormone, the promotion of the renal reabsorption of calcium, increased intestinal absorption of calcium and phosphorus, and increased calcium and phosphorus mobilization of calcium and phosphorus from bone to plasma to maintain balanced levels of each in bone and the plasma .

Zinc has three primary biological roles: catalytic, structural, and regulatory. The catalytic and structural role of zinc is well established, and there are various noteworthy reviews on these functions. For example, zinc is a structural constituent in numerous proteins, inclusive of growth factors, cytokines, receptors, enzymes, and transcription factors for different cellular signaling pathways. It is implicated in numerous cellular processes as a cofactor for approximately 3000 human proteins including enzymes, nuclear factors, and hormones .

Zinc promotes resistance to epithelial apoptosis through cell protection (cytoprotection) against reactive oxygen species and bacterial toxins, likely through the antioxidant activity of the cysteine-rich metallothioneins .

In HL-60 cells (promyelocytic leukemia cell line), zinc enhances the up-regulation of A20 mRNA, which, via TRAF pathway, decreases NF-kappaB activation, leading to decreased gene expression and generation of tumor necrosis factor-alpha (TNF-alpha), IL-1beta, and IL-8 .

There are several mechanisms of action of zinc on acute diarrhea. Various mechanisms are specific to the gastrointestinal system: zinc restores mucosal barrier integrity and enterocyte brush-border enzyme activity, it promotes the production of antibodies and circulating lymphocytes against intestinal pathogens, and has a direct effect on ion channels, acting as a potassium channel blocker of adenosine 3-5-cyclic monophosphate-mediated chlorine secretion. Cochrane researchers examined the evidence available up to 30 September 2016 .

Zinc deficiency in humans decreases the activity of serum thymulin (a hormone of the thymus), which is necessary for the maturation of T-helper cells. T-helper 1 (Th(1)) cytokines are decreased but T-helper 2 (Th(2)) cytokines are not affected by zinc deficiency in humans [A342417].

The change of Th(1) to Th(2) function leads to cell-mediated immune dysfunction. Because IL-2 production (Th(1) cytokine) is decreased, this causes decreased activity of natural-killer-cell (NK cell) and T cytolytic cells, normally involved in killing viruses, bacteria, and malignant cells [A3424].

In humans, zinc deficiency may lead to the generation of new CD4+ T cells, produced in the thymus. In cell culture studies (HUT-78, a Th(0) human malignant lymphoblastoid cell line), as a result of zinc deficiency, nuclear factor-kappaB (NF-kappaB) activation, phosphorylation of IkappaB, and binding of NF-kappaB to DNA are decreased and this results in decreased Th(1) cytokine production .

In another study, zinc supplementation in human subjects suppressed the gene expression and production of pro-inflammatory cytokines and decreased oxidative stress markers [A3424]. In HL-60 cells (a human pro-myelocytic leukemia cell line), zinc deficiency increased the levels of TNF-alpha, IL-1beta, and IL-8 cytokines and mRNA. In such cells, zinc was found to induce A20, a zinc finger protein that inhibited NF-kappaB activation by the tumor necrosis factor receptor-associated factor pathway. This process decreased gene expression of pro-inflammatory cytokines and oxidative stress markers .

The exact mechanism of zinc in acne treatment is poorly understood. However, zinc is considered to act directly on microbial inflammatory equilibrium and facilitate antibiotic absorption when used in combination with other agents. Topical zinc alone as well as in combination with other agents may be efficacious because of its anti-inflammatory activity and ability to reduce P. acnes bacteria by the inhibition of P. acnes lipases and free fatty acid levels .

Dosage

Prelamin-F dosage

Supplement for women of child-bearing potential: 0.4 mg daily.

Folate-deficient megaloblastic anaemia: 5 mg daily for 4 mth, up to 15 mg daily in malabsorption states. Continued dosing at 5 mg every 1-7 days may be needed in chronic haemolytic states, depending on the diet and rate of haemolysis.

Prophylaxis of neural tube defect in pregnancy: 4 or 5 mg daily starting before pregnancy and continued through the 1st trimester.

Prophylaxis of megaloblastic anaemia in pregnancy: 0.2-0.5 mg daily.

Vitamin A deficiency For severe deficiency with corneal changes: 500,000 unit/day for 3 days, followed by 50,000 unit/day for 2 wk and then 10,000-20,000 unit/day for 2 mth as follow-up therapy.

For cases without corneal changes: 10,000-25,000 unit/day until clinical improvement occurs (usually 1 -2 wk).

May be taken with or without food.

Side Effects

GI disturbances, hypersensitivity reactions; bronchospasm.

Hypervitaminosis A characterised by fatigue, irritability, anorexia, weight loss, vomiting and other Gl disturbances, low-grade fever, hepatosplenomegaly, skin changes, alopoecia, dry hair, cracking and bleeding lips, SC swelling, nocturia, pains in bones and joints.

Toxicity

Oral LD50 for Cr (VI) is 135 - 175 mg/kg in mouse and 46 - 113 mg/kg in rat . Oral LD50 for Cr (III) in rat is >2000 mg/kg . LD50 of chromium (III) oxide in rats is reported to be > 5g/kg . Other LD50 values reported for rats include: 3.5 g/kg (CI 3.19-3.79 g/kg) for chromium sulphate; 11.3 g/kg for chromium (III) acetate; 3.3 g/kg for chromium nitrate; and 1.5 g/kg for chromium nitrate nonahydrate .

Acute overdose of chromium is rare and seriously detrimental effects of hexavalent chromium are primarily the result of chronic low-level exposure . In case of overdose with minimal toxicity following acute ingestion, treatment should be symptomatic and supportive . There is no known antidote for chromium toxicity.

Hexavalent chromium is a Class A carcinogen by the inhalation route of exposure and Class D by the oral route . The oral lethal dose in humans has been estimated to be 1-3 g of Cr (VI); oral toxicity most likely involves gastrointestinal bleeding rather than systemic toxicity . Chronic exposure may cause damage to the following organs: kidneys, lungs, liver, upper respiratory tract . Soluble chromium VI compounds are human carcinogens. Hexavalent chromium compounds were mutagenic in bacteria assays and caused chromosome aberrations in mammalian cells. There have been associations of increased frequencies of chromosome aberrations in lymphocytes from chromate production workers . In human cells in vitro, Cr (VI) caused chromosomal aberrations, sister chromatid exchanges and oxidative DNA damage .

Copper toxicity is belevied to be due to fenton-type redox reactions occuring with high copper concentrations which produce damaging reactive oxygen species .

IPR-MUS LD₅₀ 85 mg/kg,IVN-GPG LD₅₀ 120 mg/kg, IVN-MUS LD₅₀ 239 mg/kg, IVN-RAT LD₅₀ 500 mg/kg, IVN-RBT LD₅₀ 410 mg/kg

Acute toxicity to vitamin A can occur when adults or children ingest >100x or >20x the RDA, respectively, over a period of hours or a few days. The RDA for vitamin A differs depending on age and sex and can range from 300 - 900 μg retinol activity equivalents (RAE) per day. Symptoms of acute systemic toxicity generally include mucocutaneous involvement (e.g. xerosis, cheilitis, skin peeling) and may involve mental status changes. Children are typically more susceptible to acute vitamin A toxicity - daily intakes of as little as 1500 IU/kg have been observed to result in toxicity.

Chronic vitamin A toxicity can develop following the long-term ingestion of high vitamin A doses. While there is a wide variation in the lowest toxic vitamin A dose, the ingestion of >25 000 IU daily for 6 years or 100,000 IU daily for 6 months is considered to be toxic. Chronic vitamin A toxicity can affect many organ systems and can lead to the development of osteoporosis and CNS effects (e.g. headaches).

The use of pharmacological or nutraceutical vitamin d and/or even excessive dietary intake of vitamin d is contraindicated in patients with hypercalcemia, malabsorption syndrome, abnormal sensitivity to the toxic effects of vitamin d, and hypervitaminosis D .

Hypersensitivity to vitamin d is one plausible etiologic factor in infants with idiopathic hypercalcemia - a case in which vitamin d use must be strictly restricted .

As vitamin d intake is available via fortified foods, dietary supplements, and clinical drug sources, serum concentrations and therapeutic dosages should be reviewed regularly and readjusted as soon as there is clinical improvement . Dosage levels are required to be individualized on an individual patient by patient basis as caution must be exercised to prevent the presence of too much vitamin d in the body and the various potentially serious toxic effects associated with such circumstances .

In particular, the range between therapeutic and toxic doses is quite narrow in vitamin d resistant rickets . When high therapeutic doses are used, progress should be followed with frequent blood calcium determinations .

When treating hypoparathyroidism, intravenous calcium, parathyroid hormone, and/or dihydrotachysterol may be required .

Maintenance of normal serum phosphorus levels by dietary phosphate restriction and/or administration of aluminum gels as intestinal phosphate binders in those patients with hyperphosphatemia as frequently seen in renal osteodystrophy is essential to prevent metastatic calcification .

Mineral oil interferes with the absorption of lipid-soluble vitamins, including vitamin d preparations .

The administration of thiazide diuretics to hypoparathyroid patients who are concurrently being treated with vitamin d can result in hypercalcemia .

At this time, no long term animal studies have been performed to evaluate vitamin potential for carcinogens, mutagenesis, or fertility .

As various animal reproduction studies have demonstrated fetal abnormalities in several species associated with hypervitaminosis D, the use of vitamin d in excess of the recommended dietary allowance during normal pregnancy should be avoided . The safety in excess of 400 USP units of vitamin d daily during pregnancy has not been established . The abnormalities observed are similar to the supravalvular aortic stenosis syndrome described in infants that is characterized by supravalvular aortic stenosis, elfin facies, and mental retardation .

In a nursing mother given large doses of vitamin D, 25-hydroxycholecalciferol appeared in the milk and caused hypercalcemia in her child. Caution is subsequently required when contemplating the use of vitamin d in a nursing woman, and the necessity of monitoring infants' serum calcium concentration if vitamin d is administered to a breastfeeding woman .

Adverse reactions associated with the use of vitamin d are primarily linked to having hypervitaminosis D occurring [FDA Lanel]. In particular, hypervitaminosis D is characterized by effects specific effects on specific organ systems. At the renal system, hypervitaminosis D can cause impairment of renal function with polyuria, nocturne, polydipsia, hypercalciuria, reversible asotemia, hypertension, nephrocalcinosis, generalized vascular calcification, or even irreversible renal insufficiency which may result in death . Elsewhere, hypervitaminosis D can also cause CNS mental retardation . At the level of soft tissues, it can widespread calcification of the soft tissues, including the heart, blood vessels, renal tubules, and lungs . In the skeletal system, bone demineralization (osteoporosis) in adults can occur while a decline in the average rate of linear growth and increased mineralization of bones, dwarfism, vague aches, stiffness, and weakness can occur in infants and children . Finally, hypervitaminosis D can also lead to nausea, anorexia, and constipation at the gastrointestinal level as well as mild acidosis, anemia, or weight loss via metabolic processes .

The LD(50) in animals is unknown .

According to the Toxnet database of the U.S. National Library of Medicine, the oral LD50 for zinc is close to 3 g/kg body weight, more than 10-fold higher than cadmium and 50-fold higher than mercury .

The LD50 values of several zinc compounds (ranging from 186 to 623 mg zinc/kg/day) have been measured in rats and mice .

Precaution

Treatment resistance may occur in patients with depressed haematopoiesis, alcoholism, deficiencies of other vitamins. Neonates.

Cholestatic jaundice; fat-malabsorption conditions. Monitor patients closely for toxicity. Liver impairment and children.

Interaction

Antiepileptics, oral contraceptives, anti-TB drugs, alcohol, aminopterin, methotrexate, pyrimethamine, trimethoprim and sulphonamides may result to decrease in serum folate contrations. Decreases serum phenytoin concentrations.

Decreased absorption with neomycin. Increased risk of hypervitaminosis A with synthetic retinoids eg, acitretin, isotretinoin and tretinoin. Increased risk of toxicity when used with alcohol.

Volume of Distribution

Absorbed chromium is distributed to all tissues of the body and its distribution in the body depends on the species, age, and chemical form . Circulating Cr (III) following oral or parenteral administration of different compounds can be taken up by tissues and accumulates in the liver, kidney, spleen, soft tissue, and bone .

Tetrahydrofolic acid derivatives are distributed to all body tissues but are stored primarily in the liver.

A pharmacokinetic study was done in rats to determine the distribution and other metabolic indexes of zinc in two particle sizes. It was found that zinc particles were mainly distributed to organs including the liver, lung, and kidney within 72 hours without any significant difference being found according to particle size or rat gender .

Elimination Route

Chromium compounds are both absorbed by the lung and the gastrointestinal tract. Oral absorption of chromium compounds in humans can range between 0.5% and 10%, with the hexavalent (VI) chromium more easily absorbed than the trivalent (III) form . Absorption of chromium from the intestinal tract is low, ranging from less than 0.4% to 2.5% of the amount consumed . Vitamin C and the vitamin B niacin is reported to enhance chromium absorption .

Most hexavalent Cr (VI) undergoes partial intragastric reduction to Cr (III) upon absorption, which is an action mainly mediated by sulfhydryl groups of amino acids . Cr (VI) readily penetrates cell membranes and chromium can be found in both erythrocytes and plasma after gastrointestinal absorption of Cr (IV). In comparison, the presence of chromium is limited to the plasma as Cr (III) displays poor cell membrane penetration . Once transported through the cell membrane, Cr (VI) is rapidly reduced to Cr (III), which subsequently binds to macromolecules or conjugate with proteins. Cr (III) may be bound to transferrin or other plasma proteins, or as complexes, such as glucose tolerance factor (GTF).

Copper absorption varies inversely with intake. Absorption range is 12-65%.

Folic acid is absorbed rapidly from the small intestine, primarily from the proximal portion. Naturally occurring conjugated folates are reduced enzymatically to folic acid in the gastrointestinal tract prior to absorption. Folic acid appears in the plasma approximately 15 to 30 minutes after an oral dose; peak levels are generally reached within 1 hour.

Readily absorbed from the normal gastrointestinal tract

Vitamin D3 and D2 are readily absorbed from the small intestine (proximal or distal) .

Zinc is absorbed in the small intestine by a carrier-mediated mechanism . Under regular physiologic conditions, transport processes of uptake do not saturate. The exact amount of zinc absorbed is difficult to determine because zinc is secreted into the gut. Zinc administered in aqueous solutions to fasting subjects is absorbed quite efficiently (at a rate of 60-70%), however, absorption from solid diets is less efficient and varies greatly, dependent on zinc content and diet composition .

Generally, 33% is considered to be the average zinc absorption in humans . More recent studies have determined different absorption rates for various populations based on their type of diet and phytate to zinc molar ratio. Zinc absorption is concentration dependent and increases linearly with dietary zinc up to a maximum rate [L20902].

Additionally zinc status may influence zinc absorption. Zinc-deprived humans absorb this element with increased efficiency, whereas humans on a high-zinc diet show a reduced efficiency of absorption .

Half Life

The elimination half-life of hexavalent chromium is 15 to 41 hours .

1.9 hours

Although certain studies suggest the half-life of 1,25-hydroxyvitamin D3 may be approximately 15 hours, the half-life of 25-hydroxyvitamin D3 appears to have a half-life of about 15 days . Intriguingly however, the half-lives of any particular administration of vitamin d can vary and in general the half-lives of vitamin D2 metabolites have been demonstrated to be shorter overall than vitamin D3 half-lives with this being affected by vitamin d binding protein concentrations and genotype in particular individuals .

The half-life of zinc in humans is approximately 280 days .

Clearance

Excretion of chromium is via the kidneys ranges from 3 to 50 μg/day . The 24-hour urinary excretion rates for normal human subjects are reported to be 0.22 μg/day .

Some studies propose an estimated clearance rate for 1,25-dihydroxyvitamin D as 31 +/- 4 ml/min in healthy adults .

In one study of healthy patients, the clearance of zinc was found to be 0.63 ± 0.39 μg/min .

Elimination Route

Absorbed chromium is excreted mainly in the urine, accounting for 80% of total excretion of chromium; small amounts are lost in hair, perspiration and bile . Chromium is excreted primarily in the urine by glomerular filtration or bound to a low molecular-weight organic transporter .

Copper appears to be eliminated primarily through bile .

After a single oral dose of 100 mcg of folic acid in a limited number of normal adults, only a trace amount of the drug appeared in the urine. An oral dose of 5 mg in 1 study and a dose of 40 mcg/kg of body weight in another study resulted in approximately 50% of the dose appearing in the urine. After a single oral dose of 15 mg, up to 90% of the dose was recovered in the urine. A majority of the metabolic products appeared in the urine after 6 hours; excretion was generally complete within 24 hours. Small amounts of orally administered folic acid have also been recovered in the feces. Folic acid is also excreted in the milk of lactating mothers.

The primary excretion route of vitamin D is via the bile into the feces .

The excretion of zinc through gastrointestinal tract accounts for approximately one-half of all zinc eliminated from the body .

Considerable amounts of zinc are secreted through both biliary and intestinal secretions, however most is reabsorbed. This is an important process in the regulation of zinc balance. Other routes of zinc excretion include both urine and surface losses (sloughed skin, hair, sweat) .

Zinc has been shown to induce intestinal metallothionein, which combines zinc and copper in the intestine and prevents their serosal surface transfer. Intestinal cells are sloughed with approximately a 6-day turnover, and the metallothionein-bound copper and zinc are lost in the stool and are thus not absorbed .

Measurements in humans of endogenous intestinal zinc have primarily been made as fecal excretion; this suggests that the amounts excreted are responsive to zinc intake, absorbed zinc and physiologic need .

In one study, elimination kinetics in rats showed that a small amount of ZnO nanoparticles was excreted via the urine, however, most of the nanoparticles were excreted via the feces .

Pregnancy & Breastfeeding use

Pregnancy Category A. Adequate and well-controlled human studies have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of risk in later trimesters).

Pregnancy Category A. Adequate and well-controlled human studies have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of risk in later trimesters).

Contraindication

Undiagnosed megaloblastic anaemia; pernicious, aplastic or normocytic anaemias.

Hypervitaminosis A; pregnancy (dose exceeding RDA).

Storage Condition

Store at 15-30° C.

Innovators Monograph

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