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The copolymerization and terpolymerization of leucine‐N‐carboxyanhydride, β‐benzyl aspartate‐ N‐carboxyanhydride, and valine‐N‐carboxyanhydride in dioxane, initiated with triethylamine, were investigated to determine the random nature of the terpolymer composition for potential applications as targeting drug delivery carriers. 1H NMR was used to obtain the actual monomer compositions of the polymers. The reactivity ratio of each monomer was determined with Fineman–Ross, Kelen–Tüdös, and nonlinear least‐squares curve‐ fitting methods. The product of the estimated reactivity ratios from the monomers in the binary copolymerizations indicated that random polymers were predominantly formed. On the basis of the reactivity ratios determined from the binary copolymers, Alfrey–Goldfinger equations were used to estimate the compositions of the terpolymers. There was no statistical difference between the actual monomer compositions and the calculated compositions of the terpolymers; this validated the reactivity ratios estimated by Fineman–Ross, Kelen–Tüdös, and nonlinear least‐squares curve‐ fitting methods. Therefore, the poly(leucine‐β‐Bzl‐ aspartate‐valine) synthesized in this study was primarily a random terpolymer. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 317–325, 2004

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The study describes the development of stealth solid lipid nanoparticles (SLNs) as colloidal carriers for silibinin, a drug with very low solubility. Stealth SLNs were constituted mainly of bioacceptable and biodegradable lipids, such as stearic acid and surfactant Brij 78 (polyoxyethylene 20 stearyl ether) and can incorporate amounts of silibinin up to 7.55%. Stealth-loaded SLNs were in the nanometer size range. Thermal analysis (differential scanning calorimetry) showed that silibinin was dispersed in the stealth SLNs at an amorphous state. Release of silibinin from stealth SLNs was very slow. Stealth SLNs were stable without precipitation of silibinin on storage conditions and can be proposed for their parenteral administration.

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