EFFECT OF INCORPORATION OF GELATIN, AN INTERACTIVE POLYMER ON THE MATRIX STABILITY AND RELEASE OF FENTHION FROM CROSS-LINKED MATRICES OF CARBOXYMETHYLCELLULOSE

Controlled release formulations of fenthion (10 and 20%) were prepared with sodium carboxymethylcellulose and an interactive polymer, gelati n below its isoelectric point followed by crosslinking with cupric ion . The formulations were analysed in the laboratory to monitor the phys ical integrity of the matrices and release profile of fenthion in wate r. The matrix stability up to 39 weeks with the crosslinked carboxymet hylcellulose matrices was enhanced to 55 weeks when gelatin was incorp orated. The average release rate and apparent diffusion coefficient of fenthion from these matrices fluctuated between 5.15 and 11.91 mg/wee k and 4.00 X 10(-9) and 2.01 x 10(-8) cm2/s, respectively. The analysi s of the release profiles indicated that the release pattern of fenthi on from crosslinked carboxymethylcellulose matrices exhibited a Fickia n release pattern and those that contained gelatin exhibited non-Ficki an release characteristics. These biodegradable monolithic formulation s may find useful applications in mosquito control programs with reduc ed environmental impact.