Miller R, Rheeders M
S Afr Med J. 1984 Jun 30;65(26):1045-8.
The absorption of theophylline from two commercial products labelled as having sustained-release properties (Theo-dur; Rio-Ethicals; and Euphyllin Retard; Byk-Gulden) was compared with that of a solution of theophylline (Alcophyllin syrup; Propan-Lipworth) in a multiple-dose study in smokers. As regards bioavailability, results for Theo-dur and Euphyllin Retard tables were statistically indistinguishable from that for the standard, but both products showed significantly slower absorption as reflected by longer times to attain peak concentration and lower peak concentrations. Theo-dur exhibits better sustained-release properties than Euphyllin Retard as judged from the peak/trough ratio and the persistence of concentrations from 6 hours to 12 hours after administration. Assuming linear pharmacokinetics and projecting to therapeutic doses, Euphyllin Retard results in much wider fluctuations between peak and trough concentrations (18,9 and 9,8 micrograms/ml) than does Theo-dur (13,8 and 10,2 micrograms/ml), and this product might be more acceptable in smokers if given in an 8-hourly schedule.
在一项针对吸烟者的多剂量研究中，对两种标记具有缓释特性的市售产品（茶喘平；Rio-Ethicals；和优菲林缓释片；Byk-Gulden）中茶碱的吸收情况与茶碱溶液（Alcophyllin糖浆；Propan-Lipworth）进行了比较。在生物利用度方面，茶喘平和优菲林缓释片的结果与标准品在统计学上无显著差异，但两种产品的吸收均明显较慢，表现为达到峰值浓度的时间更长且峰值浓度更低。从峰谷比以及给药后6小时至12小时浓度的持续性判断，茶喘平的缓释特性优于优菲林缓释片。假设为线性药代动力学并推算至治疗剂量，优菲林缓释片导致的峰谷浓度波动（18.9和9.8微克/毫升）比茶喘平（13.8和10.2微克/毫升）大得多，如果按每8小时给药一次，该产品在吸烟者中可能更容易接受。
