Homogeneous nanoparticles to enhance the efficiency of a hydrophobic drug, antihyperlipidemic probucol, characterized by solid-state NMR.

A low absorption in the gastrointestinal tract of hydrophobic pharmaceutical compounds in use today considerably limits their bioavailability, and therefore they are taken in large doses in order to reach the therapeutic plasma concentration, which inevitably results in undesired side effects. In this study, we demonstrate a new nanoparticle approach to overcome this problem, and our experimental results show that this approach has a high efficiency of drug loading and is easily adaptable to industrial scale. Characterization of nanoparticles containing a cholesterol-lowering hydrophobic drug, probucol, using a variety of biophysical techniques revealed higher homogeneity of these particles compared to those prepared using other approaches. Intermolecular interactions of these nanoparticles are probed at high resolution by magic angle spinning solid-state NMR experiments.

Nanoparticle processing in the solid state dramatically increases the cell membrane permeation of a cholesterol-lowering drug, probucol.

High cholesterol levels (or hypercholesterolemia) are linked with many diseases, particularly with the risk of coronary heart diseases. Probucol is commonly used to reduce cholesterol in blood. While the effectiveness of this drug highly depends on its solubility, unfortunately, it is nearly insoluble (solubility is 5 ng/mL in water). Therefore, it is essential to develop approaches to increase its solubility and bioavailability and to enhance the efficiency of the drug. Here we show that a new method increases the solubility of probucol in water and its ability to permeate cell membranes. This new method of processing the drug in a nanoparticle utilizes the grinding of PBC probucol together with sodium dodecylsulfate and methacrylic copolymer. Solid-state NMR experiments reveal the polymorphic state of probucol and the conversion of this drug from crystalline to the amorphous state, and determine its nearness to the copolymer due to the grinding process that enables the formation of nanoparticles.

Formulation and in vitro evaluation of pentazocine transdermal delivery system.

The aim of this study was to prepare a pentazocine (PTZ) matrix-type transdermal drug delivery system (TDDS) using acrylic pressure-sensitive adhesives. Among the five Duro-Tak adhesive polymers tested (87-9301, 87-2677, 87-201A, 87-2196, 87-2852), in vitro dissolution studies demonstrated the highest PTZ release flux from the Duro-Tak 87-9301 matrix. In addition, the effects of permeation enhancers, isopropyl myristate (IPM) and glyceryl monocaprylate (GEFA-C(8)), and drug content on PTZ skin permeation from prepared patches were evaluated using Franz diffusion cells fitted with hairless mouse skin. IPM and GEFA-C(8) were found to produce effective flux of PTZ at a patch concentration of 10% w/w and 5% w/w, respectively. The PTZ flux increased linearly as the loading dose increased up to 30%, whereas no further increase in flux was observed at loading doses of 40% and 50% due to drug crystallization in the matrix. Thus, the highest skin permeation rate (24.2 microg/cm(2)/h) was achieved when 30% of PTZ was loaded in Duro-Tak 87-9301 with 10% IPM and 5% GEFA-C(8). These results demonstrate the feasibility of a novel narcotic-antagonist analgesic matrix-type TDDS for PTZ.