Sintesis dan Karakterisasi Hidrogel P(SPE-ko-NIPAM) yang Bersifat Responsif Terhadap Temperatur serta Potensinya sebagai Penghantar Bahan Aktif Farmasi = Synthesis and Characterization of Hydrogel P(SPE-ko-NIPAM) Responsive to Temperature and Its Potential as Entrapment of Active Pharmaceutical Ingredients