title: Synergic effects of polymeric additives on dissolution and crystallization of acetaminophen.
abstract: OBJECTIVE
  To study how polymeric additives interact with the crystal surface of acetaminophen, and why they have different effects on drug crystallization and dissolution.
  
  
  METHODS
  The effects of different polymers on the etching patterns, crystallization and intrinsic dissolution rate (IDR) of acetaminophen have been studied.
  
  
  RESULTS
  Some polymers have shown clear consistency in their effects on the etching patterns, crystallization and IDR of acetaminophen. For example, hydroxypropyl cellulose (HPC), hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP), not only changed the etching patterns of the acetaminophen (010) face, but also inhibited acetaminophen crystallization significantly. Some polymers, like 2-hydroxyethyl cellulose (HEC), poly(vinyl alcohol) (PVA) and poly(ethylene glycol) (PEG) only had limited effects on the IDR and etching patterns, and no significant inhibitory effects on crystallization.
  
  
  CONCLUSIONS
  Even though some polymeric additives have no structural similarity to acetaminophen, they still can affect dissolution and crystallization of acetaminophen due to the synergic effects of their neighboring subunits during surface adsorption. The effects of polymeric additives on crystallization and dissolution of acetaminophen are affected not only by the specific interactions between adsorbed polymer molecules and crystal surface, but also by the mobility of the functional groups involved in the specific interactions.
authors.affiliation: Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, Indiana 47907-1336, USA. hwen03@yahoo.com
authors.forename: Hong
authors.initials: H
authors.lastname: Wen
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Morris
authors.forename: Kinam
authors.initials: K
authors.lastname: Park
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage / Q000737:chemistry*; D000327:Adsorption; D003460:Crystallization; D006860:Hydrogen Bonding; D011108:Polymers / Q000008:administration & dosage / Q000737:chemistry*; D012995:Solubility
chemical_list: D011108:Polymers; D000082:Acetaminophen