Bioequivalence of donepezil capsule and tablet in human / 药学学报

<p><b>AIM</b>To develop an HPLC-MS assay for determination of donepezil in human plasma and to investigate the pharmacokinetics and bioequivalence of donepezil capsule in healthy volunteers.</p><p><b>METHODS</b>A randomized crossover design was performed in 20 healthy volunteers. In the two study periods, a single 5 mg dose of either capsule or tablet was administered to each volunteer. After spiked with the internal standard (phenoprolamine) and treated with saturated sodium bicarbonate, plasma was extracted with ethyl acetate and separated with a C18 reversed phase column. LC-ESIMS was used in the selected ion monitoring (SIM) mode with target ions at m/z 380 for donepezil and m/z 344 for phenoprolamine. The fragmentor voltage was 120 V. The main pharmacokinetic parameters of donepezil and the bioequivalence of its two preparations were calculated.</p><p><b>RESULTS</b>The main pharmacokinetic parameters T1/2, Tmax and Cmax were (63 +/- 10) h, (3.3 +/- 0.4) h and (8.5 +/- 0.4) microgram.L-1 for the capsule; (57 +/- 9) h, (3.4 +/- 1.0) h and (8.1 +/- 1.0) microgram.L-1 for the tablet, respectively. The relative bioavailability of the donepezil capsule was 102% +/- 11%.</p><p><b>CONCLUSION</b>The assay was shown to be sensitive, accurate and convenient. The two preparations of donepezil were bioequivalent.</p>

Determination of finasteride in human plasma by HPLC-MS / 药学学报

<p><b>AIM</b>To develop an HPLC-MS assay for determination of finasteride in human plasma and to investigate the bioequivalence in healthy volunteers.</p><p><b>METHODS</b>After alkalization with sodium hydroxide, plasma was extracted with ethyl acetate and separated using a C18 column with a mobile phase of methanol-water (85:15). LC-ESI-MS was performed in the selected ion monitoring (SIM) mode using target ions at m/z 395 for finasteride and m/z 407 for the IS. The fragmentor voltage was 120 V. A randomized crossover design was performed in 20 healthy volunteers. In the two study periods, a single 10 mg dose of each tablet was administered to each volunteer.</p><p><b>RESULTS</b>Calibration curves were linear over the range 1-200 micrograms.L-1 (r = 0.9986). The limit of determination for finasteride in plasma was 0.05 microgram.L-1. The recovery of finasteride from plasma was in the range of 85.9%-98.7%. The results of variance analysis and two one-side t-test showed that there was no significant difference between the two formulations in the AUC and Cmax.</p><p><b>CONCLUSION</b>The assay was proved to be sensitive, accurate and convenient. The two formulations were bioequivalent.</p>