Vitamin c

• 1. S.BAVADHAARINI

2. CHEMICAL STRUCTURE Water soluble versatile vitamin Hexose derivative-monosaccharides Acid-enolic hydroxyl groups Strong reducing agent 3. BIOSYNTHESIS AND METABOLISM URONIC ACID CYCLE 4. SOURCES Sources:Citrus fruits(oranges,lemons),black currants;tomatoes,potato,green chillies,cabbage etc.,- Human milk-(25-50mg/dl) 5. ABSORPTION Completely absorbed from GIT Distribution both extra & intracellularly Daily intake-60-70 mg/day Plasma-0.8mg /dl Metabolites diketogluconic acid excreted in urine 6. BIOCHEMICAL FUNCTIONS Collagen formation: Post translational modification- stabilisation and formation of collagen triple helix Bone formation Synthesis of serotonin (tryptophan)and homogentisic acid (tyrosine) 7. Iron & Hb metabolism:Enhances absorption of ferrous form of iron;helps in Met Hb Hb bile pigments Maturation of erythrocytes 8. Strong antioxidant spares vit A, vit E&B-complex from oxidation Hydroxylation of glycine &carnitine Synthesis of Igs& phagocytic action of leukocytes Reduces risk of cataract ,cancer & coronary heart diseases Biosynthesis of adrenal steroids,catecholamines,oxytocin&vasopressin 9. DEFICIENCY SYMPTOMS SCURVY Capillary fragility Sore gums;loose teeth Swollen joints &brittle bones Fragile blood vessels Impaired wound healing 10. Anaemia & growth retardation Immunocompetence Subperiosteal & petechial haemorrhages 11. THERAPEUTIC USES For Scurvy:0.5-1.5g/day For Anaemia:vit c + ferrous salts (vitamin c) Injection, USP, 250 mg/mL is available in 2 mL ampules, in cartons of 25. Prophylaxis:50-100 mg/day Post-operatively:500mg daily Rapid healing of bed sores & chronic leg ulcers UTI-acidify urine -1g TDS-QID Used in common cold to cancer bt with inconsistent results 12. ADVERSE EFECTS Risk of urinary oxalate stones formation High doses cytotoxic On stoppage of therapy-Rebound scurvy Transient mild soreness may occur at the site of intramuscular or subcutaneous injection. Too-rapid intravenous administration of the solution may cause temporary faintness or dizziness 13. DRUGINTERACTIONS Limited evidence suggests that ascorbic acid may influence the intensity and duration of action of bishydroxycoumarin General Precautions Too-rapid intravenous injection is to be avoided. Laboratory Tests: Diabetics taking more than 500 mg vitamin C daily may obtain false readings of their urinary glucose test. No exogenous vitamin C should be ingested for 48 to 72 hours before amine-dependent stool occult blood tests are conducted because possible false-negative results may occur. 14. Usage in Pregnancy It is also not known whether Ascorbic Acid (vitamin c) Injection can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Ascorbic Acid Injection should be given to a pregnant woman only if clearly needed. CONTRAINDICATIONS Contraindicated in those persons who have shown hypersensitivity to any component of this preparation.