title: Blood sampling without blood draws for in vivo pharmacokinetic studies in rats.
abstract: OBJECTIVE
  Pharmacokinetic (PK) studies in rats typically involve removal of serial blood samples following dosing. This research illustrates the development of a fast in vivo microextraction technique that has the potential to partly replace current sampling techniques based on blood draws, especially in the case of small animals.
  
  
  METHODS
  The proposed sampling procedure is based on solid phase microextraction (SPME), an approach that has continued to revolutionize sampling and sample preparation ever since its discovery a decade ago. In vivo microextraction is faster than conventional methods, interferes minimally with the investigated system, minimizes errors associated with sample preparation and limits exposure of lab personnel to hazardous biological samples.
  
  
  RESULTS
  Here we show the successful application of fast microextraction during a full PK study with diazepam in rats. The results were found to correlate very well with a standard analytical method. Three calibration strategies--external, standard on the fiber, and double extraction--were employed to correlate the amount extracted with the in vivo concentration.
  
  
  CONCLUSIONS
  Our results demonstrate the unique advantages of this technique and highlight its utility as a valuable new tool for fast bioanalysis in support of in vivo sampling and PK studies, particularly during the early drug discovery process. This approach can be used not only for drugs, but also for other exogenous or endogenous compounds.
authors.affiliation: School of Pharmacy, Memorial University of Newfoundland, St. John's, NL, Canada.
authors.forename: Florin Marcel
authors.initials: FM
authors.lastname: Musteata
authors.forename: Inés
authors.initials: I
authors.lastname: de Lannoy
authors.forename: Brad
authors.initials: B
authors.lastname: Gien
authors.forename: Janusz
authors.initials: J
authors.lastname: Pawliszyn
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000818:Animals; D014151:Anti-Anxiety Agents / Q000097:blood* / Q000493:pharmacokinetics*; D019540:Area Under Curve; D002021:Buffers; D002138:Calibration; D003975:Diazepam / Q000097:blood* / Q000493:pharmacokinetics*; D006207:Half-Life; D006863:Hydrogen-Ion Concentration; D008140:Lorazepam / Q000737:chemistry; D008297:Male; D008657:Metabolic Clearance Rate; D010710:Phosphates / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000737:chemistry; D052617:Solid Phase Microextraction / Q000379:methods*; D012996:Solutions / Q000737:chemistry; D013678:Technology, Pharmaceutical
chemical_list: D000097:Acetonitriles; D014151:Anti-Anxiety Agents; D002021:Buffers; D010710:Phosphates; D012996:Solutions; D012965:Sodium Chloride; D008140:Lorazepam; D003975:Diazepam; C032159:acetonitrile