ABSTRACT
<p><b>AIM</b>To study the effect of lidocaine-dodecanol binary eutectic system on the transdermal permeation of lidocaine.</p><p><b>METHODS</b>Binary eutectic mixture of different proportions of lidocaine and dodecanol were prepared and the patch containing the binary eutectic mixture was developed. The solubilities of pure lidocaine and lidocaine from the binary eutectic system were determined in pH 7.9 phosphate buffer. The transdermal flux of lidocaine from the patches containing the binary eutectic system and pure lidocaine were measured using Franz-type single diffusion cell.</p><p><b>RESULTS</b>The melting point of the lidocaine-dodecanol binary eutectic system was markedly lower than that of pure lidocaine. The steady state transdermal flux of lidocaine from the patch of the binary eutectic system was six times as much as that of pure lidocaine patch.</p><p><b>CONCLUSION</b>The lidocaine-dodecanol binary eutectic system could produce high thermodynamic activity of the drug and the high driving force for transdermal permeation of lidocaine.</p>
Subject(s)
Animals , Administration, Cutaneous , Anesthetics, Local , Pharmacokinetics , Dodecanol , Chemistry , Drug Combinations , Drug Stability , Guinea Pigs , Lidocaine , Pharmacokinetics , Skin Absorption , SolubilityABSTRACT
<p><b>AIM</b>To determine clonidine in rabbit plasma by LC-MS.</p><p><b>METHODS</b>The LC-MS system consisted of Waters Alliance 2790 HPLC and Micromass ZQ-4000 MS. The HPLC was performed by using XTerra C18 (150 mm x 2.1 mm ID, 5 microm). The mobile phase, consisting of acetonitrile/ammonium hydrogen carbonate solution, was maintained to a flow-rate of 0.2 mL x min(-1) and the linear gradient elution was adopted. Mass spectrum was obtained by using electrospray ionization interface and the m/z of SIM was 230.</p><p><b>RESULTS</b>The average recovery was high and the method was reproducible. The calibration curve showed good linearity in the range of 1 - 80 microg x L(-1), the lowest limit of detection was 0.05 microg x L(-1). The Cmax, AUC0-t, and Tmax value of the pharmacokinetics parameter were (27 +/- 9) microg x L(-1), (5,352 +/- 1,121) microg x L(-1), (79 +/- 17) h.</p><p><b>CONCLUSION</b>The results demonstrated that the method had high sensitivity, good selectivity, accuracy and precision. It is used to determine the clonidine concentration in plasma. The transdermal patch can deliver clonidine to the surface of rabbit skin stably for periods of up to 1 week after a single application.</p>