The absorption characteristics of vitamin E acetate (VEA) formulated into a dry emulsion system after its oral administration to beagle dogs were determined and compared to those of two different dosage forms (an oily mixture of the drug with cottonseed oil and an oil (drug)-in-water emulsion). The three dosage forms were administered in a crossover fashion to six nonfasting subjects, and the drug absorption was assessed from the plasma concentration of the major metabolite (free vitamin E). VEA formulated in the dry emulsion was rapidly absorbed, which suggested that a considerable amount was released as reformed emulsion droplets in the gastrointestinal tract as well as in water in vitro. Based on the analysis of variance, no significant differences in bioavailability parameters (AUC, Cmax or Tmax) were observed among the three dosage forms.

In this article we report the results of two size selection methods that are based on interfacial interaction between nanosize particles, magnetite in this case, anionic surfactants, and nonpolar solvents. It is proposed that by selecting a suitable surfactant type and/or conditions to modify the particle–particle separation distance, only smaller particles can be stabilized against aggregation and settling making a size sensitive separation possible. Using this phenomenon, an effective size selection at the nanosize level has been achieved and the preliminary results are presented here. Depending on the conditions, stable suspensions of nearly monodispersed nanoparticles of magnetite (diameter less than 10 nm and standard deviation, σ, below 0.2) were obtained from polydispersed powders (less than 40 nm in diameter and σ around 0.6) synthesized from aqueous solutions at 25 °C. Magnetization measurements of the fractions confirmed the effectiveness of the developed size selection methods.

No abstract

No abstract

No abstract