title: Continuous Preparation of 1:1 Haloperidol-Maleic Acid Salt by a Novel Solvent-Free Method Using a Twin Screw Melt Extruder.
abstract: Salts are generally prepared by acid-base reaction in relatively large volumes of organic solvents, followed by crystallization. In this study, the potential for preparing a pharmaceutical salt between haloperidol and maleic acid by a novel solvent-free method using a twin-screw melt extruder was investigated. The pH-solubility relationship between haloperidol and maleic acid in aqueous medium was first determined, which demonstrated that 1:1 salt formation between them was feasible (pHmax4.8; salt solubility 4.7 mg/mL). Extrusion of a 1:1 mixture of haloperidol and maleic acid at the extruder barrel temperature of 60 °C resulted in the formation of a highly crystalline salt. The effects of operating temperature and screw configuration on salt formation were also investigated, and those two were identified as key processing parameters. Salts were also prepared by solution crystallization from ethyl acetate, liquid-assisted grinding, and heat-assisted grinding and compared with those obtained by melt extrusion by using DSC, PXRD, TGA, and optical microscopy. While similar salts were obtained by all methods, both melt extrusion and solution crystallization yielded highly crystalline materials with identical enthalpies of melting. During the pH-solubility study, a salt hydrate form was also identified, which, upon heating, converted to anhydrate similar to that obtained by other methods. There were previous reports of the formation of cocrystals, but not salts, by melt extrusion.1H NMR and single-crystal X-ray diffraction confirmed that a salt was indeed formed in the present study. The haloperidol-maleic acid salt obtained was nonhygroscopic in the moisture sorption study and converted to the hydrate form only upon mixing with water. Thus, we are reporting for the first time a relatively simple and solvent-free twin-screw melt extrusion method for the preparation of a pharmaceutical salt that provides material comparable to that obtained by solution crystallization and is amenable to continuous manufacturing and easy scale up.
authors.affiliation: Department of Chemical and Materials Engineering, National Central University , 300 Jhong-Da Road, Jhong-Li District, Taoyuan City 32001, Taiwan R.O.C.|Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University , 8000 Utopia Parkway, Queens, New York 11439, United States.
authors.forename: Hung Lin
authors.initials: HL
authors.lastname: Lee
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University , 8000 Utopia Parkway, Queens, New York 11439, United States.
authors.forename: Jaydip M
authors.initials: JM
authors.lastname: Vasoya
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University , 8000 Utopia Parkway, Queens, New York 11439, United States.
authors.forename: Marilia de Lima
authors.initials: ML
authors.lastname: Cirqueira
authors.affiliation: Department of Chemical and Materials Engineering, National Central University , 300 Jhong-Da Road, Jhong-Li District, Taoyuan City 32001, Taiwan R.O.C.
authors.forename: Kuan Lin
authors.initials: KL
authors.lastname: Yeh
authors.affiliation: Department of Chemical and Materials Engineering, National Central University , 300 Jhong-Da Road, Jhong-Li District, Taoyuan City 32001, Taiwan R.O.C.
authors.forename: Tu
authors.initials: T
authors.lastname: Lee
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University , 8000 Utopia Parkway, Queens, New York 11439, United States.
authors.forename: Abu T M
authors.identifier: 0000-0002-2596-715X
authors.initials: AT
authors.lastname: Serajuddin
mesh_terms: D000085:Acetates / Q000737:chemistry; D002626:Chemistry, Pharmaceutical / Q000379:methods; D003460:Crystallization / Q000379:methods; D004339:Drug Compounding / Q000379:methods; D006220:Haloperidol / Q000737:chemistry*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008298:Maleates / Q000737:chemistry*; D012995:Solubility; D012996:Solutions / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D013696:Temperature; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D000085:Acetates; D008298:Maleates; D012996:Solutions; D012997:Solvents; C007650:ethyl acetate; C030272:maleic acid; D006220:Haloperidol
keywords: cogrinding; eutectic formation; haloperidol; haloperidol−maleic acid salt; maleic acid; melt crystallization; pharmaceutical salt; twin-screw melt extrusion