Few researches are directed at drug delivery systems for b-lapachone (b-lap), a powerful anticancer agent but with limited pharmaceutical use. To overcome its limitations, we investigated controlled delivery systems of b-lap in simulated gastric fluids in vitro from chitosan (CS) and alginate (AL) hydrogel beads with purpose for oral administration. The AL-CS hydrogel beads were formed by coacervation and were characterized by morphology, swelling ratio, and their physicochemical properties. The hydrogel beads, with sizes of roughly 1 mm, presented good stability, and low porosity. The in vitro drug release profile was in good agreement with kinetics profiles and the Fickian model indicating diffusion as the release mechanism, with low burst effect, especially in an acid medium and allowing a prolonged release of $ 72 h (pH 1.2; k 2 ¼ 0.19 6 0.04) and (pH 7.4; k 2 ¼ 0.20 6 0.01). The beads were resistant to the acid medium and may be an alternative for b-lap therapy of colorectal cancer. V C 2012Wiley Periodicals, Inc. J Appl Polym Sci 126: E408-E417, 2012

Food sharing with immatures is an important and relatively well studied aspect of infant care in many cooperative species. A key point that has not yet been fully addressed, however, is how increasing the difficulty of obtaining food influences the willingness of breeders and helpers to provision immature offspring. We used captive golden headed lion tamarins (Leontopithecus chrysomelas) to examine how breeders and helpers differ in provisioning juvenile individuals according to the level of difficulty of obtaining food. The level of difficulty in obtaining food was varied by placing the food inside tubes that allowed access only by adults. When food acquisition became more difficult, food sharing with juveniles and breeding females increased significantly. Begging calls by breeding females and juveniles increased during the experimental condition, which probably led to increases in food sharing. Breeders and helpers did not differ in their contribution to provisioning when food was easily available, nor did they differ in their contribution when food was difficult to obtain. Breeding males in callitrichids have a prominent role in transferring food to offspring, but contrary to our expectations, they did not increase food transfer in the experimental condition. An unexpected result was the increased investment of the breeding female into her current offspring when the level of difficulty of obtaining food was higher. We suggest that breeding lion tamarin females are not as constrained by reproductive costs as breeding females of other callitrichids. Degree of reproductive skew is hypothesized as a factor affecting the contribution of breeders and helpers to offspring care in cooperative breeding mammals, though we suggest that more studies are needed to validate such a generalization.