59
Views
1
CrossRef citations to date
0
Altmetric
Original

Analysis of nano drug carriers towards optimum release rate

&
Pages 243-252 | Published online: 09 Jul 2009
 

Abstract

The aim of this paper is to determine which polymer shape (sphere, hemisphere, cylinder, tablet, cuboid, tetrahedron or octahedron) is best for zero kinetics drug delivery and for sustained nanoparticle release. We applied the Carslaw and Jaeger heat diffusion equations of a sphere with same order of its effective surface area to volume ratio as a reference, to predict how drug delivery would occur in other shapes. The assumption of the heat diffusion analogy in the present study of negligible drug particles is sensible since the drug at nano scale is tiny and thus nearly ‘massless’. From tests involving changing the micro-carrier configuration, we can confirm that shape is an important factor to consider when examining drug release rates, to achieve zero-order design. The preliminary analysis suggests that a hemisphere shape is more promising in achieving zero-order drug release rate, followed by a tablet shape of L = 2Rs, 3Rs, a tetrahedron, a cylindrical shape with L = 3Rs, 2Rs, a sphere, a cuboid shape with L = 3Rs, 2Rs, and finally an octahedron. This is due to the larger effective surface area, given the same parameters and surrounding conditions. In other words, a hemisphere shape reaches zero order in the shortest possible time and thus permits sustained zero-order particle release rate. Based on the ratio between the surface area of a micro-carrier and its volume, we further derived the drug release equation of cylinder/tablet shaped micro-carrier. By introducing h as an index of the similarity of the drug release rate to a desirable zero-order drug release rate, we obtained a relationship between different length/radius (L/R) values of cylinder/tablet shapes and the index h. From this relationship, we find the best L/R ratio that can achieve a drug release process most similar to a zero-order drug release process. Future work is to include optimization of the lipid matrixes.

Reprints and Corporate Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

To request a reprint or corporate permissions for this article, please click on the relevant link below:

Academic Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

Obtain permissions instantly via Rightslink by clicking on the button below:

If you are unable to obtain permissions via Rightslink, please complete and submit this Permissions form. For more information, please visit our Permissions help page.