A new simple controlled release delivery system

The chemical pulping of wood without subsequent drying affords low-cost hollow fibers with microporous multilamellar cell walls saturated with water. Simple impregnation of these never-dried pulp fibers with solutions of biologically active chemicals followed by drying yields collapsed cellulose ribbons containing entrapped impregnant. The release characteristics of exemplary composites containing an analgesic (acetylsalicylic acid), a growth stimulant (alpha-naphthylacetic acid), or a herbicide (2,4-dichlorophenoxyacetic acid) are reported both for in vitro and in vivo evaluations.