( MEYHYLCOBALAMINE2500 MCG, FOLIC ACID , NIACINAMIDE) & ( VITAMIN C 150 MG ) COMBIPACK
M.R.P: – 42
Methylcobalamin is a cobalamin (MeB12) used in peripheral neuropathy, diabetic neuropathy etc. It is a form of vitamin B12. This vitamer is one of two active coenzymes used by B-12 dependent enzymes in the body, and is specifically the B-12 form used by 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR), also known as methionine synthase. Methylcobalamin is notable for being one of the few examples in nature of a bona fide organometallic bond. Methylcobalamin has been studied in conjunction with sleep-wake rhythm disorders, where it appears to yield benefits, but at a low or inconsistent level. It is used in treating diseases of vitamin B12 deficiency (such as pernicious anemia), or diseases of effective B12 deficiency, such as vitamin B12 metabolic pathway pathologies. One study suggests that once absorbed, methylcobalamin may be retained in the body better than cyanocobalamin. PHARMACODYNAMICS
Mechanism of Action: –
1. Mecobalamin: – Mecobalamin is the neurologically active form of vitamin B12 and occurs as a water-soluble vitamin in the body. It is a cofactor in the enzyme methionine synthase, which functions to transfer methyl groups for the regeneration of methionine from homocysteine. In anaemia, it increases erythrocyte production by promoting nucleic acid synthesis in the bone marrow and by promoting maturation and division of erythrocytes.
2. Folic Acid: – Folic acid reduced by enzymes folate reductase and dihydrofolate reductase and forms dihydrofolic acid tetrahydrofolic acid respectively. Tetrahydrofolic acid acts as a coenzyme which mediates a number of one carbon transfer reactions by carrying a methyl group as an adduct. It involves a number of reactions such as 1).conversion of homocysteine to methionine. 2).synthesis of thymidylate which is an essential constituent of DNA from methylene-tetrahydrofolic acid. 3). Conversion of serine to glycine by tetrahydrofolic acid and forms methylene-tetrahydrofolic acid. 4).to introduce carbon units at position 2 and 8 during de novo purine synthesis requires formyl-tetrahydrofolic acid and methenyl-tetrahydrofolic acid.5).generation and utilization of \”formate pool\”. 6).For mediating formino group transfer in histidine metabolism. Folic acid is required to maintain normal erythropoiesis and nucleoprotein synthesis.
3.Niacinamide: – Niacinamidean important compound functioning as a component of the coenzyme NAD. Its primary significance is in the prevention and/or cure of blacktongue and pellagra. Most animals cannot manufacture this compound in amounts sufficient to prevent nutritional deficiency and it therefore must be supplemented through dietary intake.
4. Vitamin C: – Ascorbic Acid (vitamin C) is a water-soluble vitamin indicated for the prevention and treatment of scurvy, as ascorbic acid deficiency results in scurvy. Collagenous structures are primarily affected, and lesions develop in bones and blood vessels. Administration of ascorbic acid completely reverses the symptoms of ascorbic acid deficiency. In humans, an exogenous source of ascorbic acid is required for collagen formation and tissue repair by acting as a cofactor in the posttranslational formation of 4-hydroxyproline in -Xaa-Pro-Gly- sequences in collagens and other proteins. Ascorbic acid is reversibly oxidized to dehydroascorbic acid in the body. These two forms of the vitamin are believed to be important in oxidation-reduction reactions. The vitamin is involved in tyrosine metabolism, conversion of folic acid to folinic acid, carbohydrate metabolism, synthesis of lipids and proteins, iron metabolism, resistance to infections, and cellular respiration.
1. MECOBALAMIN: –
Absorption: – Peak plasma concentrations after 3 hr (oral); 0.9 hr (IM); 3 min (IV). • Excretion: – Via urine.
2. FOLIC ACID
Absorption: Well absorbed orally
Distribution: Widely distributed in the body and highest concentration is seen in liver. It appears in the CSF and breast milk
Metabolism: Metabolized in to N-methyl tetrahydrofolic acid in liver
Excretion: Extra drug is excreted unchanged in urine. A small portion of folate is lost by a combination of urinary and fecal excretion and oxidative cleavage of molecule. • Onset of Action for Folic Acid Oral: 20 to 30minutes I.V.: 5 minutes I.M.:10 to 20minutes • Duration of Action for Folic Acid Oral: 3 to 6 hours I.V.:3 to 6minutes I.M.:3 to 6hours
Absorption: – 70% to 90%
Protein Binding: – 25%
Metabolism: – Hepatic. Ascorbic acid is reversibly oxidised (by removal of the hydrogen from the enediol group of ascorbic acid) to dehydroascorbic acid. The two forms found in body fluids are physiologically active. Some ascorbic acid is metabolized to inactive compounds including ascorbic acid-2-sulfate and oxalic acid.
Indications for Folic Acid
1. Megaloblastic anaemia
2. Folic acid deficiency
3. Anaemias of pregnancy
4. Nutritional anaemia
6. Tropical sprue
7. Non tropical sprue Indications for Mecobalamin
Mecobalamin is primarily indicated in conditions like
1. Congenital cobalamine malabsorption,
2. Congenital intrinsic factor deficiency,
3. Homocystenemia, Methylmalonylacidurias,
4. Peripheral neuropathy,
5. Pernicious anaemia,
6. Post gastrectomy vit B-12 deficiency,
7. Transcobalamin II deficiency,
8. Vitamin B12 deficiency.
Indications for Niacinamide
1. Niacin and niacinamide are used in the prophylaxis and treatment of pellagra.
2. Niacin is used as adjunctive therapy in addition to diet and other measures to lower elevated serum cholesterol and triglycerides in patients with type II, III, IV or V hyperlipoproteinemia.
3. Niacinamide is not effective for the reduction of serum cholesterol levels.
Indications for Vitamin C 1.
Used to treat vitamin C deficiency, scurvy, delayed wound and bone healing, urine acidification, and in general as an antioxidant.
3. It has also been suggested to be an effective antiviral agent.