ABSTRACT
Total parenteral nutrition [TPN] replaces and maintains essential nutrients in patients in whom oral or tube feedings are contraindicated or inadequate. A nutritional assessment must be carried out before initiating TPN in order to determine nutritional needs and any metabolic changes due to the patient's underlying condition, medications or concurrent therapies. In addition to carbohydrates, proteins and fats, certain amounts of micronutirents are also added to TPN solutions. These micronutrients include electrolytes, vitamins, and trace minerals. This review highlights some basic concepts regarding the use and formulation of TPNs along with their advantages and disadvantages and the importance of water soluble vitamins B[2] and B[12] in human nutrition
ABSTRACT
Formylmethylflavin [FMF] is a major intermediate product in the aerobic and anaerobic photolysis of riboflavin [RF] and is highly sensitive to light and hydrolysis. It is more sensitive to light as compared to RF. FMF is further degraded into lumichrome [LC], carboxymethylflavin [CMF] in acidic medium, and LC, CMF and lumiflavin [LF] in alkaline medium. When FMF is exposed to light it is degraded in to LC and LF via a photoreduction and CMF through photooxidation pathways. In aerobic and anaerobic conditions, RF when exposed to light is excited to singlet state [1RF] and from singlet to triplet state [3RF]. This is followed by the conversion of 3RF into a semiquinone radical [RFH] and this radical further disproportionate to form an oxidized RF and a cyclic intermediate, which is further oxidized to FMF and degradation products [LC, LF, CMF]
ABSTRACT
Vitamin B[6] [pyridoxine] is closely associated with the functions of the nervous, immune and endocrine systems. It also participates in the metabolic processes of proteins, lipids and carbohydrates. Pyridoxine deficiency may result in neurological disorders including convulsions and epileptic encephalopathy and may lead to infant abnormalities. The Intravenous administration of pyridoxine to patients results in a dramatic cessation of seizures. A number of analytical methods were developed for the determination of pyridoxine in different dosage forms, food materials and biological fluids. These include UV spectrometric, spectrofluorimetric, mass spectrometric, thin-layer and highperformance liquid chromatographic, electrophoretic, electrochemical and enzymatic methods. Most of these methods are capable of determining pyridoxine in the presence of other vitamins and complex systems in micro g quantities. The development and applications of these methods in pharmaceutical and clinical analysis mostly during the last decade have been reviewed
Subject(s)
Humans , Animals , Pyridoxine/deficiency , Chemistry Techniques, Analytical , Biomarkers/bloodABSTRACT
Vitamin A is a group of unsaturated nutritional organic compounds, that includes retinol, retinal, retinoic acid, and several provitamin A carotenoids, among which beta-carotene is the most important. Most compounds within the vitamin A family are soluble in fat and are essential for numerous processes within the body. Vitamin A [retinol] and derivatives play an essential role in metabolic functioning of the retina, the growth of bone, reproduction, and the immune response. Dietary vitamin A is derived from a variety of carotenoids found in plants. It is enriched in the liver, egg yolk and the fat component of dairy products. It is required for normal vision, reproduction, embryonic development, cell and tissue differentiation and immune function in animals and humans. Vitamin A deficiency [VAD] is also known to be involved with different specific disease conditions such as xerophthalmia, polynephritis, keratomalacia and ulceration leading to irreversible blindness along with increased susceptibility to infections and abnormalities in reproduction. Vitamin A is sensitive to light and air and its ester forms are more susceptible to oxidation. The important analytical techniques used for the analysis of the vitamin A and its derivatives are high-performance liquid chromatography [HPLC], spectrophotometry and voltammetry. These methods have been found to be accurate and precise and have been applied successfully to the analysis of drug formulations
ABSTRACT
In the present work the photo degradation of riboflavin in the presence of acetate bulfer has been studied. The assay of riboflavin and its photoproducts in degraded solution has been carried out simultaneously using a multi component spectrometer method. Acetate buffer has been found to catalyze the photo degradation of riboflavin and the apparent first-order rate constants for the reaction at pH 4.2 in the presence of 0.125 -0.625 M acetate buffer range from 0.45 [pH 5.6] to 2.05 X 10-2 min-1. The k-pH profile for these reactions shows a maximum around pH 4.2 indicating the participation of different species of the molecule in the reaction. The decrease in the rate of the reaction after the maximum is due to a change in the redox behavior of riboflavin. The results indicate that acetate buffer at a low concentration is suitable for maintaining the pH of vitamin preparations
ABSTRACT
The photodegradation of cyanocobalamin at pH 4.0 in the presence of ascorbic acid has been studied. Hydroxocobalamin has been identified as a major degradation product of the reaction. Cyanocobalamin and hydroxocoblamin in degraded solutions have been assayed at 550 and 525nm by a two-component spectrophotometirc method in which ascorbic acid does not interfere. The apparent first-order rate constants for the photodegradation of cyanocoblaamin at pH 4.0 are in the range of 2.21-2.70 x 10-3 min-1. These values indicate that the photodegradation of cyanocobalamin is enhanced in the presence of ascorbic acid by mutual interaction and needs protective measures to control the degradation of the vitamin
ABSTRACT
Riboflavin [Vitamin B2]is the precursor in the biosynthesis of the coenzymes flavin mononucleotide [FMN] and flavin adenine dinucleotide [FAD]. The metabolic functions of riboflavin are carried out by these coenzymes, which participate in numerous vital oxidation-reeducation processes. Flavoproteins catalyze dehydrogenations, hydroxylation, oxidative decarboxylations, dioxygenatiosn and reducations of oxygen to hydrogen peroxide reactions. The powerful anti-oxidant activity of the vitamin is derived from its role as a precursor to FMN and FAD. A major protective role against lipid peroxides is provided by the glutathione redox cycle. Glutathione peroxidase breaks down reactive lipid peroxides. The enzyme requires y-Glutamyl-L-cysteine-glysine [GSH]that is generated from its oxidizing form glutathione disulfide [GSSG] by the FAD containing enzyme glutathione reductase. The administration of riboflavin may be helpful in certain inborn errors of metabolism. The riboflavin deficiency may have a beneficial role in malaria. The clinical analysis of riboflavin is largely carried out by high-performance liquid chromatographic methods [HPLC]
ABSTRACT
alpha-Tocopherol [vitamin E] is a lipid-soulde antioxidant. Its deficiency symptoms depend on alpha -tocopherol content, uptake and utilization. Vitamin E concentrations are dependents on its unoxidised state in the body Vitamin E deficiency has been related with cognitive impairment and Alzheimer's disease. The low concentration of serum a-tocopherol and ascorbic acid may lead to inflammatory and cardiovascular diseases. The determination of alpha -tocopherol in clinical samples has largely been carried out by UV spectrophotometry and high-performance liquid chromatography
ABSTRACT
The major biochemical role of nicotinamide [vitamin 63] is its involvement in redox reactions and energy metabolism. The biological forms of nicotinamide are nicotinamide adenine dinucleotide [NAD] and nicotinamide adenine dinucleotide phosphate [NADP] coenzymes. Nicotinamide is a component of vitamin B-complex and is used in combination with other vitamin B compounds in pharmaceutical preparations. Several analytical methods have been used for the assay of nicotinamide in commercial products. These methods include high-performance liquid cinematography [HPLC], mass spectrometry in the multiple reaction modes [LC/UV/MS/MRM], liquid chromatographic-isotope detection mass spectrometry [LC/DMS], and planner chromatography-multiple detection by electro-spray mass spectrometry [ES/MS], capillary zone electrophoresis [CZE], thin-layer chromatography [TLC]-densitometry, differential pulse polarography and cyclic voltametry. The clinical analysis of nicotinamide involves the application of liquid chromatography-tandem mass spectrometry [LC-MS/MS], high-performance liquid chromatography [HPLC] and capillary electrochromatgraphy
ABSTRACT
Vitamin D [mainly ergocalciferol and cholecalciferol] and their metabolites exist in a complex environment in biological systems. The identification and determination of the individual vitamin Ds in these systems require specific methods. The purified components of vitamin D can be determined by UV spectrometry and colorimetry. However the best method for the separation and determination of ergocalciferol and cholecalciferol and their metabolites is high-performance liquid chromatography. This technique in combination with mass spectrometry [LC-MS] can be used for the simultaneous separation and identification of vitamin D components and metabolites. The technique is also useful for the identification of vitamin D in steroidal mixture
ABSTRACT
Folic acid is a water-soluble vitamin, which is involved in hematopoiesis and the synthesis of amino acids and DNA. It is widely used for the treatment of megaloblastic anemia. Tetrahydrofolic acid is the fully reduced form of folic acid and is the parent compound of a variety of coenzymes that serve as carriers of one-carbon groups in metabolic reactions. The daily use of supplemental folic acid periconceptionally significantly reduces the risk of neural tube defects. The genetic polymorphisms affecting the structure-function of folate-related enzymes have been associated with the increased risk of birth defects and chronic diseases including vascular diseases and different types of cancers. Therapeutic use of folic acid has been found to greatly reduce the prevalence of these diseases
ABSTRACT
The resin based filling materials were introduced in dentistry at the end of the 1940s. Poor color stability, low stiffness, lack of adhesion to tooth structure were the major drawback of this class of restorative material. Polymerization shrinkage is one of the challenges wh1th needs improvement of this material to many methods were developed. Light curing units which were the major breakthrough and the energy efficiency of the different light sources have also been discussed
ABSTRACT
Pharmaceutical care is a necessary element of health care system and is provided for the direct benefit of the patient. Community pharmacists are considered the professionals of choice in this area as they are in direct contact with a large number of populations. In order to properly implement the concept of pharmaceutical care, it is necessary to first fulfill the legal requirements as those are directly related to the sales of drugs. The current scenario of pharmacies / medical stores in terms of legal aspects was investigated by carrying out a field survey. A questionnaire was prepared and distributed to 250 local pharmacies and medical stores at various locations of Karachi. The questionnaire contained some basic information in terms of the presence of pharmacist, qualification of non-pharmacist, presence of a valid license, availability of compounding facility in the pharmacy, whether the selling of non-OTC drugs is on prescription or without prescription, storage facility of drugs, disposal of expired drugs and awareness of drug act, 1976 and related rules. Out of 250 visited medical stores and pharmacies, 160 participated in the survey, whose results are summarized in the study
ABSTRACT
Thiamine is a component of vitamin B-complex and is used in the treatment of beriberi. The active form of the vitamin is thiamine pyrophosphate [TPP] which serves as a co-enzyme in various biochemical reactions. It is commercially available in the form of vitamin B-complex and multivitamin preparations. The clinical analysis of the vitamin and its esters is carried out by spectrophotometric, fluorimetric, high performance liquid chromatographic and flow-injection turbidimetric methods. The rates of catabolism and loss of thiamine indicate that in the absence of the vitamin, functional and clinical abnormalities occur in humans within a few weeks period. Thiamine absorption takes place in the intestine by two parallel mechanisms, i.e., saturable active transport and simple diffusion. The bioavailability of thiamine can be assessed by determining maximal thiamine concentration [Cmax] and its time [tmax] in plasma and hemolysates, the area under concentration time curve [AUC], and thiamine excretion in 24-hr urine
ABSTRACT
The present review describes the biochemical importance of cyanocobalamin [vitamin B12] and its role in the biosynthesis of adenosylcobamide and methylcobamide co-enzymes which perform important functions in human metabolism. Cyanocobalamin deficiency is a significant public health problem particularly among the elderly. It has been reported that the prevalence of vitamin B12 deficiency may be as high as 30-40% among the elderly due to food B12 malabsorption. Various analytical methods have been used for the clinical assay of cyanocobalamin in biological samples. These include microbiological, radioisotope, spectrophotometric and chromatographic methods