Richardson C J, Blocka K L, Ross S G, Verbeeck R K
Clin Pharmacol Ther. 1985 Jan;37(1):13-8. doi: 10.1038/clpt.1985.4.
Piroxicam kinetics were studied after a single, oral, 20-mg capsule was taken by 12 young (six women, six men) and 13 elderly (seven women, six men) healthy subjects. Plasma samples were drawn for 216 hr after dosing. Plasma protein binding was studied in vitro by equilibrium dialysis and piroxicam concentrations were measured by HPLC with ultraviolet detection. The apparent volume of distribution was smaller in elderly women (7.8 +/- 0.4 l) than in young men (11.3 +/- 0.3 l) and elderly men (10.8 +/- 0.8 l). There were no such differences when the apparent volume of distribution was normalized for total body weight. There was a strong correlation between total body weight and apparent volume of distribution in all subjects (r = 0.83). Plasma protein binding of piroxicam ranged from 98.90% to 99.54% bound and was not affected by age or sex. Piroxicam body clearance in elderly women (0.026 +/- 0.002 ml/min/kg) was approximately 33% lower than in young women (0.039 +/- 0.003 ml/min/kg). This difference was reflected in different t1/2s of 61.7 and 44.9 hr. Predicted steady-state plasma piroxicam concentrations were 5.7 micrograms/ml in young women, 5.4 micrograms/ml in young men, 5.7 micrograms/ml in elderly men, and 9.3 micrograms/ml in elderly women. The high value in elderly women results from the lower piroxicam body clearance and total body weight. Our data suggest that healthy elderly women eliminate piroxicam at a slower rate than healthy young women. The clinical significance of these data needs to be assessed in patients.
对12名年轻（6名女性，6名男性）和13名老年（7名女性，6名男性）健康受试者口服一粒20毫克胶囊后的吡罗昔康动力学进行了研究。给药后采集血浆样本216小时。通过平衡透析体外研究血浆蛋白结合情况，并用带紫外检测的高效液相色谱法测量吡罗昔康浓度。老年女性的表观分布容积（7.8±0.4升）比年轻男性（11.3±0.3升）和老年男性（10.8±0.8升）小。当将表观分布容积按总体重进行标准化时，不存在此类差异。所有受试者的总体重与表观分布容积之间存在很强的相关性（r = 0.83）。吡罗昔康的血浆蛋白结合率在98.90%至99.54%之间，不受年龄或性别的影响。老年女性的吡罗昔康体内清除率（0.026±0.002毫升/分钟/千克）比年轻女性（0.039±0.003毫升/分钟/千克）低约33%。这种差异反映在不同的半衰期上，分别为61.7小时和44.9小时。预测的稳态血浆吡罗昔康浓度在年轻女性中为5.7微克/毫升，在年轻男性中为5.4微克/毫升，在老年男性中为5.7微克/毫升，在老年女性中为9.3微克/毫升。老年女性中的高值是由于吡罗昔康体内清除率和总体重较低。我们的数据表明，健康老年女性清除吡罗昔康的速度比健康年轻女性慢。这些数据的临床意义需要在患者中进行评估。
