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
- Authors:
- 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
- Authors:
- 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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