<![CDATA[Abstrak. Pada penelitian ini, matrik hidrogel berbasis karagenan dibuat dan diaplikasikan untuk mengontrol pelepasan urea. Tujuan penelitian ini adalah mempelajari pengaruh konsentrasi glutaraldehid terhadap kecepatan pelepasan urea dan menyusun model kecepatan pelepasan urea. Film karagenan dimodifikasi secara kimiawi menggunakan ikatan silang atau crosslinking dengan glutaraldehid. Larutan karagenan 7 g/100 mL dicetak menjadi lembaran dan kemudian dikeringkan sehingga diperoleh lapisan film. Film direndam dalam larutan glutaraldehid dengan konsentrasi tertentu selama 2 menit dan dilanjutkan dipanaskan pada suhu 110oC selama 20 menit. Film yang dihasilkan dicuci dengan etanol dan dikeringkan. Pengisian urea ke dalam matrik film menggunakan metode difusi. Film kering direndam dalam larutan urea 0,074 g/mL selama satu jam dan selanjutnya dikeringkan. Kecepatan pelepasan urea dari film ke dalam media air dievaluasi berdasarkan data konsentrasi urea dalam cairan sebagai fungsi waktu. Berdasarkan hasil penelitian didapatkan bahwa semakin besar konsentrasi glutaraldehid (1-5%) menyebabkan urea yang tersimpan di dalam film semakin rendah. Model matematika yang diusulkan dapat mewakili peristiwa pelepasan urea dari film. Film berbasis karagenan yang dihasilkan berpotensi sebagai matrik pengontrol pelepasan urea. Kata kunci: crosslinking, glutaraldehid, hidrogel, karagenan, urea. Abstract. Controlled Release Matrices of Urea from Carrageenan: Effect of Glutaraldehyde Concentration. In this study, carrageenan-based hydrogel matrices were prepared and applied for urea controlled release. The aim of this work was to study the effect of glutaraldehyde concentration on the rate of urea release in water. Carrageenan films were chemically modified by crosslinking with glutaraldehyde. The films were prepared by casting the aqueous carrageenan 7 g/100 mL and then followed by drying. The films obtained were immersed in certain glutaraldehyde concentration for 2 min and then heated in the oven at 110oC for 20 min. The crosslinked films were washed using ethanol and then air-dried until the weight is constant. The dried films were immersed in a urea solution (0.074g/ml) for 1 hr and then dried. The rate of urea release was determined by measuring the urea concentration in water as a function of time of release. Results showed that higher glutaraldehyde concentration (1–5%) produced films with less urea content. The proposed mathematic model of urea release from the film can represent the rate of urea release. The prepared carrageenan-based film has the potential for controlling of urea release. Keywords: carrageenan, crosslinking, glutaraldehyde, hydrogel, urea. Graphical Abstract]]>
