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Purpose: Improvement of drug solubility is an important issue in pharmaceutical dosage form development.In order to enhance dissolution of poorly water-soluble drugs, solid dispersions prepared by using organic solvents have been extensively investigated.The hot-melt extrusion methods also attract much attention due to solvent-free and continuous dry-processing.This study was focused on application of newly developed aqueous poly(vinyl alcohol) derivatives (PVA copolymers) as solid dispersion matrix: the PVA copolymers, which are synthesized by co-polymerizing VA with acrylic acid and methyl methacrylate, have been developed as hard capsule and film coating materials.Methods: The PVA copolymer-based solid dispersions were prepared by two different methods i.e.,ultrasound assisted compaction (USAC) and hot-melt extrusion (HME).In USAC, the mixtures of nifedipine (NIF) as poorly soluble model drug with PVA copolymer were molded by ultrasound irradiation up to 1200 J.In HME, the mixtures of NIF PVA copolymer and glycerin were extruded by using melt indexer.Results: It was found from differential scanning calorimetry and powder X-ray diffractometry that NIF in the products from USAC existed in an amorphous state over 1000 J, leading to a high apparent solubility of 35.6 μg/mL, which was 4.5 times higher than that of original NIF crystals (8.0 μg/mL).The capability of PVA copolymer to make NIF amorphous was superior to that of polyvinylpyrrolidone (PVP).In HME, when prepared at operating temperatures above 160℃, NIF exhibited a solubility 3.7 times higher than that of NIF crystal.Conclusion: These results from the ultrasound assisted compaction and hot-melt extrusion suggested that the newly developed PVA copolymer might be efficiently applied to solid dispersion formulation with a high performance.