title: Analysis of diltiazem in Lipoderm transdermal gel using reversed-phase high-performance liquid chromatography applied to homogenization and stability studies.
abstract: A simple and novel method for the extraction and quantification of diltiazem hydrochloride was developed and applied to homogenization and stability studies. The method used solid phase extraction coupled with reversed-phase high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection. Validation showed inter-day recoveries ranging from 84.00 to 96.52% with relative standard deviations ranging from 12.01 to 15.94%. Intra-day recoveries ranged from 67.95 to 106.1% with relative standard deviations less than 5%. The method showed excellent linearity from 50 to 250 mg/ml in undiluted gel (R2 = 0.996). The homogenization study showed good homogenization using both 50 and 100 depression techniques. Diltiazem was stable at a concentration of 246 mg/ml for 30 days and at a concentration of 99.6 mg/ml for 60 days no matter the storage conditions explored in this study.
authors.affiliation: North Carolina State University, College of Veterinary Medicine, Center for Chemical Toxicology Research and Pharmacokinetics, 4700 Hillsborough St. Raleigh, NC 27606, USA. jib@cctrp.ncsu.edu
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Buur
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Baynes
authors.forename: James L
authors.initials: JL
authors.lastname: Yeatts
authors.forename: Gigi
authors.initials: G
authors.lastname: Davidson
authors.forename: Teresa C
authors.initials: TC
authors.lastname: Defrancesco
mesh_terms: D002121:Calcium Channel Blockers / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004110:Diltiazem / Q000032:analysis*; D004355:Drug Stability; D005782:Gels; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D012015:Reference Standards; D015203:Reproducibility of Results
chemical_list: D002121:Calcium Channel Blockers; D005782:Gels; D004364:Pharmaceutical Preparations; D004110:Diltiazem