Predicting the Drug Release Kinetics of Matrix Tablets

In this paper we develop two mathematical models to predict the release kinetics of a water soluble drug from a polymer/excipient matrix tablet. The first of our models consists of a random walk on a weighted graph, where the vertices of the graph represent particles of drug, excipient and polymer, respectively. The graph itself is the contact graph of a multidisperse random sphere packing. The second model describes the dissolution and the subsequent diffusion of the active drug out of a porous matrix using a system of partial differential equations. The predictions of both models show good qualitative agreement with experimental release curves. The models will provide tools for designing better controlled release devices.Comment: 17 pages, 7 figures; Elaborated at the first Workshop on the Application of Mathematics to Problems in Biomedicine, December 17-19, 2007 at the University of Otago in Dunedin, New Zealan

Development and In Vitro Evaluation of a Zerumbone Loaded Nanosuspension Drug Delivery System

Zerumbone extracted from the volatile oil of rhizomes available from the Zinigiber zerumbet has promising pharmacological activity. However, it has poor aqueous solubility and dissolution characteristics. To improve this, a nanosuspension formulation of zerumbone was developed. Nanosuspensions were formulated using high-pressure homogenization (HPH) with sodium dodecyl sulphate (SDS) and hydroxypropylmethylcellulose (HPMC) as stabilizers; the formulation was optimized and freeze dried. The optimized nanosuspension product was evaluated using an optical light microscope, photon correlation spectroscopy (PCS), polydispersity index, zeta potential, SEM, differential scanning calorimetry (DSC) and FT-IR. The physical stability of the nanosuspensions was evaluated for 30 days at 4 °C, 25 °C, and 37 °C. To validate the theoretical benefit of the increased surface area, we determined an in vitro saturation solubility and dissolution profile. The mean particle size, polydispersity index and zeta potential of the zerumbone nanosuspensions stabilized by SDS versus HPMC were found to be 211 ± 27 nm vs. 398 ± 3.5 nm, 0.39 ± 0.06 vs. 0.55 ± 0.004, and −30.86 ± 2.3 mV vs. −3.37 ± 0.002 mV, respectively. The in vitro saturation solubility and dissolution revealed improved solubility for the zerumbone nanosuspension. These results suggested that the nanosuspensionlization improves the saturation solubility and dissolution profile of zerumbone, which may facilitate its use as a therapeutic agent in the future

Recent update on nanoemulgel as topical drug delivery system

Being an emerging transdermal delivery tool, nanoemulgel, has proved to show surprising upshots for the lipophilic drugs over other formulations. This lipophilic nature of majority of the newer drugs developed in this modern era resulting in poor oral bioavailability, erratic absorption, and pharmacokinetic variations. Therefore, this novel transdermal delivery system has been proved to be advantageous over other oral and topical drug delivery to avoid such disturbances. These nanoemulgels are basically oil-in-water nanoemulsions gelled with the use of some gelling agent in it. This gel phase in the formulation is nongreasy, which favors user compliance and stabilizes the formulation through reduction in surface as well as interfacial tension. Simultaneously, it can be targeted more specifically to the site of action and can avoid first-pass metabolism and relieve the user from gastric/systemic incompatibilities. This brief review is focused on nanoemulgel as a better topical drug delivery system including its components screening, formulation method, and recent pharmacokinetic and pharmacodynamic advancement in research studies carried out by the scientists all over the world. Therefore, at the end of this survey it could be inferred that nanoemulgel can be a better and effective drug delivery tool for the topical system