title: Simultaneous determination of caffeine, 8-chlorotheophylline, and chlorphenoxamine hydrochloride in ternary mixtures by ratio-spectra zero-crossing first-derivative spectrophotometric and chemometric methods.
abstract: A ratio-spectra zero-crossing first-derivative spectrophotometric method and 2 chemometric methods have been used for the simultaneous determination of ternary mixtures of caffeine (A), 8-chlorotheophylline (B), and chlorphenoxamine hydrochloride (C) in bulk powder and dosage forms. In the ratio-spectra zero-crossing first-derivative spectrophotometric technique (1DD), calibration curves were linear in the range of 4-20 microg/mL for A, B, and C (r = 0.9992, 0.9994, and 0.9976, respectively). The measurements were carried out at 212, 209.2, and 231.4 nm for A, B, and C, respectively. The detection limits for A, B, and C were calculated to be 0.24, 0.34, and 0.13 microg/mL, and the percentage recoveries were 99.1 +/- 0.89, 100.1 +/- 0.95, and 100.1 +/- 1.0, respectively. Two chemometric methods, namely, the partial least-squares (PLS) model and the principal component regression (PCR) model, were also used for the simultaneous determination of the 3 drugs in the ternary mixture. A training set consisting of 15 mixtures containing different ratios of A, B, and C was used. The concentration used for the construction of the PLS and PCR models varied between 4 and 25 microg/mL for each drug. These models were used after their validation for the prediction of the concentrations of A, B, and C in mixtures. The detection limits for A, B, and C were calculated to be 0.13, 0.15, and 0.14 microg/mL, respectively, and the percent recoveries were found to be 99.8 micro 0.96, 99.9 micro 0.94, and 99.9 micro 1.18, respectively, for both methods. The 3 proposed procedures are rapid, simple, sensitive, and accurate. No preliminary separation steps or resolution equations are required; thus, they can be applied to the simultaneous determination of the 3 drugs in commercial tablets and suppositories or in quality-control laboratories.
authors.affiliation: Cairo University, Faculty of Pharmacy, Department of Analytical Chemistry, Kasr El-Aini St, PO Box 11562, Cairo, Egypt.
authors.forename: Khadiga M
authors.initials: KM
authors.lastname: Kelani
mesh_terms: D002110:Caffeine / Q000032:analysis*; D002138:Calibration; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D000431:Ethanol / Q000032:analysis; D005021:Ethylamines / Q000032:analysis*; D015233:Models, Statistical; D025341:Principal Component Analysis; D012044:Regression Analysis; D012996:Solutions; D013053:Spectrophotometry; D013488:Suppositories; D013607:Tablets; D013678:Technology, Pharmaceutical / Q000379:methods*; D013806:Theophylline / Q000031:analogs & derivatives* / Q000032:analysis; D013997:Time Factors
chemical_list: D004338:Drug Combinations; D005021:Ethylamines; D012996:Solutions; D013488:Suppositories; D013607:Tablets; D002110:Caffeine; D000431:Ethanol; C100100:chlorphenoxamine; D013806:Theophylline; C030093:8-chlorotheophylline