INVESTIGADORES
VIDALES Ana Maria
artículos
Título:
Effect of the drug/excipient ratio in matrix type controlled release systems: computer simulation study
Autor/es:
VILLALOBOS, R.; GANEM, A.; CORDERO, S.; VIDALES, A M; DOMINGUEZ, A.
Revista:
DRUG DEVELOPMENT AND INDUSTRIAL PHARMACY
Editorial:
Taylor & Francis
Referencias:
Año: 2005 vol. 31 p. 535 - 543
ISSN:
0363-9045
Resumen:
The main objective of this work is to study the drug release
behavior from inert matrix systems by using computer simulation. This study
allowed us to propose a new statistical method to evaluate the drug percolation
threshold as a function of the exposed surface area of the device. The matrix
system was simulated as a simple cubic lattice. The sites of the lattice were
randomly occupied at various drugexcipient ratios. By simulating a diffusive
process, the drug was delivered from the matrix system. The obtained release
profiles were fitted to two different models: near the excipient percolation
threshold, the square root of the time was well fitted, whereas close to (but
above) the drug percolation threshold, the power law described accurately the
release data. A relationship between the initial drug load and the amount of
drug trapped inside the matrix system at infinite time was found. This
relationship was conveniently described by an error function. Percolation
thresholds in the matrix systems were determined from the latter relationship
by using a nonlinear regression method. The assessment of percolation
thresholds depends on the exposed surface area of the matrix systems.
Moreover, estimated percolation thresholds were in agreement with the
predicted values stated in the percolation theory.