title: Solid phase extraction and liquid chromatographic determination of sildenafil and N-demethylsildenafil in rat serum with basic mobile phase.
abstract: HPLC method for the determination of sildenafil and its metabolite (N-demethylsildenafil) in rat serum has been developed. The technique included a solid phase extraction of the serum samples on a [poly(divinylbenzene-co-N-vinylpyrrolidone)] solid phase extraction sorbent. After conditioning, the cartridge was loaded with 0.5 mL of buffered serum containing internal standard. Elution was made with 1 mL of acetonitrile. After evaporation of the eluates to dryness and reconstitution with methanol, the samples were analyzed on Kromasil C18 column phase with phosphate buffer 0.05 M/acetonitrile: 54/46, pH 8. Detection was carried out using a photodiode array detector. For sildenafil and demethylsildenafil, full validation of the proposed method was provided (linearity range, calibration curves, average extraction efficiency; average intra-day and interday variabilities, limit of detection, limit of quantification, specificity). The proposed method was successfully utilised to quantify sildenafil and N-demethylsidenafil in rat serum for a pharmacokinetic study.
authors.affiliation: Faculté de Chimie, USTHB, B.P. No. 32, El-Alia, Bab-Ezzouar, Alger, Algeria. hguermouche@voila.fr
authors.forename: M H
authors.initials: MH
authors.lastname: Guermouche
authors.forename: K
authors.initials: K
authors.lastname: Bensalah
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000818:Animals; D002021:Buffers; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D010726:Phosphodiesterase Inhibitors / Q000097:blood* / Q000493:pharmacokinetics; D010879:Piperazines / Q000097:blood* / Q000378:metabolism / Q000493:pharmacokinetics; D011687:Purines / Q000097:blood / Q000493:pharmacokinetics; D011744:Pyrimidinones / Q000097:blood* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D000068677:Sildenafil Citrate; D013056:Spectrophotometry, Ultraviolet; D013450:Sulfones / Q000097:blood* / Q000493:pharmacokinetics
chemical_list: D000097:Acetonitriles; D002021:Buffers; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D011744:Pyrimidinones; D013450:Sulfones; C109995:UK 103320; D000068677:Sildenafil Citrate; C032159:acetonitrile