title: New approach application of data transformation in mean centering of ratio spectra method.
abstract: Most of mean centering (MCR) methods are designed to be used with data sets whose values have a normal or nearly normal distribution. The errors associated with the values are also assumed to be independent and random. If the data are skewed, the results obtained may be doubtful. Most of the time, it was assumed a normal distribution and if a confidence interval includes a negative value, it was cut off at zero. However, it is possible to transform the data so that at least an approximately normal distribution is attained. Taking the logarithm of each data point is one transformation frequently used. As a result, the geometric mean is deliberated a better measure of central tendency than the arithmetic mean. The developed MCR method using the geometric mean has been successfully applied to the analysis of a ternary mixture of aspirin (ASP), atorvastatin (ATOR) and clopidogrel (CLOP) as a model. The results obtained were statistically compared with reported HPLC method.
authors.affiliation: Pharmaceutical Analytical Chemistry, Department of Chemistry, Al-Aqsa University, P.O. Box 4051, Gaza, Palestine.
authors.forename: Mahmoud M
authors.initials: MM
authors.lastname: Issa
authors.affiliation: Analytical Chemistry, Department of Chemistry, Al-Aqsa University, P.O. Box 4051, Gaza, Palestine. Electronic address: alaaash2002@yahoo.com.
authors.forename: R'afat M
authors.initials: RM
authors.lastname: Nejem
authors.affiliation: National Institute of Research for Electrochemistry and Condensed Matter, Bucharest, Romania.
authors.forename: Raluca Ioana Stefan
authors.initials: RI
authors.lastname: Van Staden
authors.affiliation: Pharmaceutical and Medicinal Chemistry Department, Pharmaceutical and Drug Industries Research Division, National Research Center, Dokki, Giza 12662, Egypt. Electronic address: haboulenein@yahoo.com.
authors.forename: Hassan Y
authors.initials: HY
authors.lastname: Aboul-Enein
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000032:analysis*; D000924:Anticholesteremic Agents / Q000032:analysis*; D001241:Aspirin / Q000032:analysis*; D000069059:Atorvastatin / Q000032:analysis*; D000077144:Clopidogrel; D016011:Normal Distribution; D010975:Platelet Aggregation Inhibitors / Q000032:analysis*; D013053:Spectrophotometry / Q000379:methods*; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000032:analysis
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D000924:Anticholesteremic Agents; D010975:Platelet Aggregation Inhibitors; D000069059:Atorvastatin; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin
keywords: Arithmetic mean; Aspirin; Atorvastatin; Clopidogrel; Mean centering of ratio spectra – geometric mean