title: RP-HPLC assay of doxycycline in human saliva and gingival crevicular fluid in patients with chronic periodontal disease.
abstract: A reversed-phased HPLC method with fluorescence detection was optimized and validated for determination of DOXY in human saliva and gingival crevicular fluid (GCF) with tetracycline as internal standard. Single step extraction with acetonitrile for both types of samples was performed. The separation was achieved at Zorbax Extend-C18 analytical column at 30°C. Mobile phase was consisted of an aqueous phase containing magnesium acetate, ammonium acetate, Na₂EDTA, triethyl-ammonium acetate buffered to pH 7.5 with ammonium hydroxide solution and acetonitrile. The volume ratio of the buffered water mixture of salts and acetonitrile was 86:14. Fluorescence detector was set at λex=380 nm and λem=520 nm. Under the optimized experimental conditions, good linearity was found in the range of 5.0-250.0 ng/mL for GCF with LOD of 1.63 ng/mL and LOQ of 4.93 ng/mL and 20.0-500.0 ng/mL for saliva with LOD of 6.36 ng/mL and LOQ of 19.28 ng/mL. This method was successfully applied for determination of DOXY in saliva and GCF obtained from patients with chronic periodontal disease.
authors.affiliation: Department of Pharmacy, University of Niš, Faculty of Medicine, Bulevar dr Zorana Đinđića 81, 18000 Niš, Serbia. mdenic84farm@gmail.com
authors.forename: Marko S
authors.initials: MS
authors.lastname: Denić
authors.forename: Slavica M
authors.initials: SM
authors.lastname: Sunarić
authors.forename: Ljiljana G
authors.initials: LG
authors.lastname: Kesić
authors.forename: Ivan Z
authors.initials: IZ
authors.lastname: Minić
authors.forename: Radmila R
authors.initials: RR
authors.lastname: Obradović
authors.forename: Marija S
authors.initials: MS
authors.lastname: Denić
authors.forename: Milica S
authors.initials: MS
authors.lastname: Petrović
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002908:Chronic Disease; D004318:Doxycycline / Q000032:analysis* / Q000627:therapeutic use; D005883:Gingival Crevicular Fluid / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D010510:Periodontal Diseases / Q000188:drug therapy*; D015203:Reproducibility of Results; D012463:Saliva / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D004318:Doxycycline