1. Calculation of partial components of bioavailability in slow release formulations using model-independent methods
- Author
-
José M. Lanao, M.T. Vicente, and M.L. Sayalero
- Subjects
Pharmacokinetics ,Laplace transform ,Stereochemistry ,Chemistry ,Slow Release Formulation ,Pharmaceutical Science ,Function (mathematics) ,Deconvolution ,Biological system ,Dosage form ,Convolution ,Bioavailability - Abstract
In certain slow release formulations the total dose of drug is subdivided into at least two fractions with different release capacities; these may display different degrees of bioavailability. In this type of formulation, calculation of the amount of biavailability by conventional methods does not permit one to differentiate the contribution of the different dose fractions to the total bioavailability of the formulation. This paper develops a model-independent method that permits optimization of the different components of bioavailability regarding amount and rate, combining convolution/deconvolution methods as well as non-linear regression. The method calculates bioavailability parameters by optimization of a prescribed input function in the form of a Laplace transform using the MULTI(FILT) program. The serum level curve after the administration of a slow release formulation is used as a response function obtained by convolution between a prescribed input function and a weighting function expressed as a polyexponential. The method was tested using simulated serum level data with added random error. In all cases the bioavailability parameters were calculated with good precision.
- Published
- 1995