SVIBOR - Papers quoted in CC - project code: 3-01-136


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Papers quoted in Current Contents on project 3-01-136

Quoted papers: 11
Other papers: 23
Total: 34

Title: Determination of drug absorption rate by iterative deconvolution without reference to intravenous data -Theory of method

Jovanović, Veljko (18926)
FrancetiĆ, Igor
Journal: Acta Pharmaceutica
Number: 1
ISSN: 1330-0075
Volume: 44
Year: 1994
Pages: from 27 to 44
Number of references: 23
Language: engleski
Summary: A deconvolution method for calculating drug absorption rate without references to intravenous data is described. The method is based on two-compartment open model and involves estimation of the ai exponents describing iv drug disposition rate and k21 constant (first order mass rate constant associated with the movements of drug from compartment 2 to compartment 1). It was demonstrated that estimation of ai exponents could be done on the basis of the analysis of the part of plasma drug concentration after oral administration, C1*(t), when the absorption process is finished (t>Tf). Constant k21 for the calculation of drug absorption, i(t), could be selected from data on the iterative deconvolution of the C1*(t). The mathematical background of the iterative deconvolution was analyzed with simulated data obtained by convolution of a triangle input. In condition of inaccurate estimation of ai exponents, the proposed method of iterative deconvolution exhibits a high degree of robustness. The same characteristics of robustness are noticed when a response is not a consequence of an input into a two-compartment model. Iterative deconvolution provides data on the absorption process expressed in one litre of serum. In case that drug is eliminated by urine, the absorption rate could be expressed in mg per hour. The method will be a useful tool for studying the bioavailability and absorption of drugs.
Keywords: deconvolution, absorption rate

Title: Relation between Intestinal Calcium and Strontium Absorption

Jovanović, Veljko (18926)
Đurović, Srđan
Journal: Collegium Antropologicum (Supplement)
ISSN: 0350-6134
Volume: 18
Year: 1994
Pages: from 79 to 85
Number of references: 8
Language: engleski
Summary: For the determination of calcium absorption recently it were proposed that stable strontium could be applied. In the present work we analyze resemblance between Ca and Sr absorption. The present study is aimed to gives an simple method of the estimation of true Sr absorption based on the Sr content in one blood sample.The investigation is based on data obtained after an oral administration of 152 mg (1.9 mmol) of Sr in healthy subjects. One of the subject is chosen for a more detailed study including administration of 100 mg (2.5 mmol) of elemental Ca and radioactive 47Ca isotope. To the same subject 85Sr is intravenously adminis- tered. According to the elaborated THEORETICAL MODEL entire con- tent of absorbed tracer is positioned in a pool, V(t), which is time dependent. Specific radioactivity in this pool is equal to serum specific radioactivity,o.s(t). So the absorp- tion can be calculated as the product of serum radioactivity and a time depending Ca-pool.As a golden standard for absorption estimation, numerical deconvolution method is ap- plied using KONDEK computer numerical deconvolution pro- gram. The difference between Sr and Ca pool was within limits of experimental error. Both pools have time dependent values. The present investigation demonstrated that the concept of an expanding Ca -pool can be used in description of serum radioactivity after oral administration, and the same concept could be suitable for the description of exchange process between strontium in serum and bone mineral.The authors believe that presented models permit accurate estimation of Sr absorption. They pointed out that from methodological viewpoint the Sr absorption test is not an expensive one and anticipate that Sr absorption test will become a method of choice for population studies of Ca absorption.
Keywords: Calcium, Strontium, Intestinal absorption

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