Dendrimer nanocomposites (DNC) are hybrid nanoparticles formed by the dispersion and immobilization of guest atoms or small clusters in dendritic polymer matrices. They have a great potential in biomedical applications due to their controlled composition, predetermined size, shape and variable surface functionalities. In this work, d=5–25 nm spherical nanoparticles composed of gold and poly(amidoamine) (PAMAM) dendrimers have been selected to demonstrate this nanoparticle based concept. {Au(0)n-PAMAM} gold dendrimer nanocomposites with a well-defined size were synthesized and imaged by transmission electron microscopy both in vitro and in vivo. DNC have also the potential to be used for imaging and drug delivery vehicles either by utilizing bioactive guests or through the incorporation of radioactive isotopes, such as Au-198.

Dendrimer nanocomposites (DNC) are hybrid nanoparticles formed by the dispersion and immobilization of guest atoms or small clusters in dendrimer matrices. They have a great potential in biomedical applications due to their controlled composition, predetermined size, shape and surface functionalities. In this work, nanocomposites of gold and poly(amidoamine) dendrimers {Au(0) n -PAMAM} have been selected to demonstrate this nanoparticle based concept. {Au(0) n -PAMAM} gold dendrimer nanocomposites with a well-defined size have been synthesized and imaged by TEM both in vitro and in vivo. Dendrimer nanocomposites have also the potential to be used as drug delivery vehicles either utilizing bioactive guests or incorporating radioactive isotopes. Radioactive dendrimer nanocomposites, e.g. {198-Au}, can be delivered to the tumor either by means of injecting the active nanoparticles directly into the tumor microvasculature or by intravenous injection. Both specific or non-specific targeting can be utilized in this process to achieve appropriate transfer.

Polyamidoamine (PAMAM) dendrimers have steadily grown in popularity in the past decade in a variety of disciplines, ranging from materials science to biomedicine. This can be attributed in part to their use in applications that range from computer toners to medical diagnostics. PAMAM dendrimers are safe and nonimmunogenic, and can function as highly efficient cationic polymer vectors for delivering genetic material into cells. They have been shown to be as efficient or more efficient than either cationic liposomes or other cationic polymers (e.g. polyethylenimine, polylysine) for in vitro gene transfer. This article will focus on the application of PAMAM dendrimers as a nonviral gene delivery vector from the initial discovery of this capacity to the most recent experimental findings.

Purpose. To determine the mechanism(s) by which effervescence induces penetration enhancement of a broad range of compounds ranging in size, structure, and other physiocochemical properties across rat and rabbit small intestinal epithelium.

Oral effervescent formulations were originally developed as a means to mask unpleasant tastes typically associated with drug compounds. Although these delivery systems provide a palatable saline taste, effervescence may also produce physiological changes within the body. When effervescent solutions (50 ml) were administered to a cannulated mixed breed canine, there was an increase in pressure gradient across the gastroduodenal junction resulting in an altered pattern from fasted to a ‘pseudo-fed’ state. These solutions also created an increase in total discharge volume and mean solid content when compared with controls. The results are indicative of an increase in mucosal and gastric secretions along with stripping of the mucus layer due to mechanical turbulence. In-vitro diffusion studies showed an increase in benzoic acid permeability across rabbit ileum tissue in the presence of carbon dioxide (CO2). This effect also occurred with nitrogen indicating the enhancement mechanism is not unique to the chemical entity CO2, but rather to epithelial disruption which was verified by electrophysiology measurements. In-situ rat single-pass perfusion studies also showed an increase in benzoic acid absorption with relatively rapid (20 min) tissue recovery after CO2 exposure.