Sarheed Omar, Rasool Bazigha K Abdul
Department of Pharmaceutics, RAK College of Pharmaceutical Sciences, Ras Al-Khaimah Medical and Health Sciences University, Ras Al-Khaimah, UAE.
Open Biomed Eng J. 2011;5:14-24. doi: 10.2174/1874120701105010014. Epub 2011 Mar 15.
It has now been known for over a decade that low frequency ultrasound can be used to effectively enhance transdermal drug penetration - an approach termed sonophoresis. Mechanistically, acoustic cavitation results in the creation of defects in the stratum corneum that allow accelerated absorption of topically applied molecules. The aim of this study was to develop an optimised sonophoresis protocol for studying transdermal drug delivery in vitro. To this end, caffeine was selected as a model hydrophilic drug while porcine skin was used as a model barrier. Following acoustic validation, 20kHz ultrasound was applied for different durations (range: 5 s to 10 min) using three different modes (10%, 33% or 100% duty cycles) and two distinct sonication procedures (either before or concurrent with drug deposition). Each ultrasonic protocol was assessed in terms of its heating and caffeine flux-enhancing effects. It was found that the best regimen was a concurrent 5 min, pulsed (10% duty cycle) beam of SATA intensity 0.37 W/cm(2). A key insight was that in the case of pulsed beams of 10% duty cycle, sonication concurrent with drug deposition was superior to sonication prior to drug deposition and potential mechanisms for this are discussed.
十多年来，人们已经知道低频超声可用于有效增强经皮给药——这种方法被称为超声透入疗法。从机制上讲，声空化会导致角质层产生缺陷，从而加速局部应用分子的吸收。本研究的目的是开发一种优化的超声透入疗法方案，用于体外研究经皮给药。为此，选择咖啡因作为亲水性模型药物，使用猪皮作为屏障模型。经过声学验证后，使用三种不同模式（10%、33%或100%占空比）和两种不同的超声处理程序（在药物沉积之前或与药物沉积同时进行），对20kHz超声施加不同的持续时间（范围：5秒至10分钟）。根据其加热和咖啡因通量增强效果对每个超声方案进行评估。结果发现，最佳方案是同时进行5分钟、占空比为10%、声强为0.37W/cm²的脉冲波束。一个关键的发现是，对于占空比为10%的脉冲波束，与药物沉积同时进行超声处理优于在药物沉积之前进行超声处理，并讨论了其潜在机制。
