title: Amphiphilic amino acid copolymers as stabilizers for the preparation of nanocrystal dispersion.
abstract: The recent advance of particle size engineering in nanometer ranges has widened the formulation opportunities of relatively water-insoluble drugs. However, the 'nanoformulation' suffers from a lack of systematic understanding about the requirements of polymeric stabilizers. Furthermore, the polymers that can be used for the preparation of nanocrystals are so limited that finding a proper stabilizer for a given formulation is often difficult. In this study, amino acid copolymers whose properties can systematically be tailored are developed, and their morphological and compositional effects are investigated. Copolymers containing lysine (K) as their hydrophilic segments, and phenylalanine (F) or leucine (L) as their hydrophobic segments successfully produce stable nanocrystals (200-300 nm) in water, while copolymers of K and alanine (A) could not generate nanosized particles. Not the morphology but the hydrophobicity of copolymers seems to be a critical parameter in the preparation of drug nanocrystals by wet comminution. The effective stabilization performance of copolymers requires the hydrophobic moiety content to be higher than 15 mol%. Comminution for only 5 min is long enough for nanocrystal preparation, and the crystallinity of drug is found intact after the processing.
authors.affiliation: Department of Nano Science and Engineering, Biomaterials Research Group, Sejong University, Kwang-Jin-Gu, Gun-Ja-Dong 98, Seoul, South Korea.
authors.forename: Jonghwi
authors.initials: J
authors.lastname: Lee
authors.forename: Soo-Jeong
authors.initials: SJ
authors.lastname: Lee
authors.forename: Ji-Yeun
authors.initials: JY
authors.lastname: Choi
authors.forename: Ji Youn
authors.initials: JY
authors.lastname: Yoo
authors.forename: Cheol-Hee
authors.initials: CH
authors.lastname: Ahn
mesh_terms: D000596:Amino Acids / Q000008:administration & dosage* / Q000737:chemistry; D004355:Drug Stability; D057927:Hydrophobic and Hydrophilic Interactions; D049329:Nanostructures; D010316:Particle Size; D011108:Polymers / Q000008:administration & dosage
chemical_list: D000596:Amino Acids; D011108:Polymers