Physiological Availability of the Vitamins

Melnick, Daniel; Hochberg, Melvin; Oser, Bernard L.

doi:10.1093/jn/30.2.67

Cited by 49 publications

(6 citation statements)

References 25 publications

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“…L approximately 50 per cent of the administered vitamin. This is in accordance with the findings of Melnick et al (1945), who used fluorometric methods of analysis. There was little change in the excretion of nicotinic acid.…”

Section: Recovery Of Riboflavin and Nicotinic Acid Added To Urinesupporting

confidence: 93%

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The Microbiological Assay of Riboflavin and Nicotinic Acid in Urine

Fitzpatrick¹,

Tompsett²

1949

Journal of Clinical Pathology

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Section: Recovery Of Riboflavin and Nicotinic Acid Added To Urinesupporting

confidence: 93%

“…There was little change in the excretion of nicotinic acid. This is in accor- dance with the findings of Melnick et al (1940) and Huff and Perlzweig (1943) that, following ingestion of nicotinamide, Nl methylnicotinamide is the main metabolite excreted in the urine.…”

Section: Recovery Of Riboflavin and Nicotinic Acid Added To Urinesupporting

confidence: 81%

The Microbiological Assay of Riboflavin and Nicotinic Acid in Urine

Fitzpatrick¹,

Tompsett²

1949

Journal of Clinical Pathology

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“…His presentation started by reviewing the historical evolution of the statistical concepts adopted in BE testing. It was highlighted the fact that the first intimations of BE problems originated from multisource drug products and also inspired by vitamins, aspirin, and tolbutamide (1)(2)(3)(4)(5)(6)(7). The measures of BE were initially defined regarding rate and extent of absorption.…”

Section: Within-subject Variability: Design Determination and Demonstrmentioning

confidence: 99%

“…Various sporadic in vivo observations in the 1950s and 1960s raised the first intimations of bioequivalence (BE) with multi-source drug products (1)(2)(3)(4)(5)(6)(7). It was realized that product efficacy depends on the proportion of the drug which is ultimately absorbed (extent of absorption) from its formulation and how rapidly the drug absorption is being held (rate of absorption).…”

Section: Introductionmentioning

confidence: 99%

Bioavailability and Bioequivalence: Focus on Physiological Factors and Variability

Karalis

Macheras

Peer³

et al. 2008

Pharm Res

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This is a summary report of the EUFEPS & COST B25 conference on Bioavailability and Bioequivalence which focused on physiological factors and variability. This conference was held at The Royal Olympic Hotel in the centre of Athens (Greece) during the 1-2 of October in 2007. The issues discussed in the conference involved physiological factors affecting drug absorption, the role of pre-systemic effects on bioavailability (BA), the impact of variability in bioequivalence (BE) studies, and a final closing panel session on unresolved issues in BA/BE regulations. Several important aspects of drug absorption were highlighted. It was presented how the complexity of gastrointestinal (GI) physiology and the site dependent absorption can impact on drug BA. Similarly, the effects of food and formulation were also studied. The second session focused on integrating the complexities of GI into modeling the inter-individual variability of absorption and the prediction of first-pass metabolism from in-vitro data. The necessity to measure metabolites, the value of Biopharmaceutical Classification System (BCS), and the more recently proposed Biopharmaceutical Drug Disposition Classification System (BDDCS) were assessed as well. This session closed with presentations of pharmacokinetic software delegates. In the second day of the conference, the problem of high intra-subject variability in BE studies was analyzed. Study design considerations, the use of multiple-dose studies and the role of statistics in BE were also highlighted. Finally, the current thinking of regulatory authorities (EMEA and US-FDA) was presented. The conference closed with a last session on unresolved issues in the regulatory level.

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“…Although such effects are more likely to occur at low drug to adjuvant ratios, the possible existence of the excipient as a chemisorbed layer on the drug has been mentioned as a factor that might cause similar effects at high drug to adjuvant ratios (2). To determine whether silica gel in a tablet would influence the physiological availability of ascorbic acid, the human bioassay technique described by Melnick et al, (9) was applied to several tablet formulations. In this test, comparison is made between the extra urinary excretion of the vitamin following dosage with the test sample and that following administration of the vitamin in pure form.…”

Section: (C) Effect Of Orher Tabletmentioning

confidence: 99%