University Hospital Prince of Asturias, University of Alcalá, Madrid, Spain.
Curr Drug Deliv. 2012 May;9(3):231-42. doi: 10.2174/156720112800389098.
Hearing aids or cochlear implants constitute almost exclusively the treatment options currently available to patients suffering from sensorineural hearing loss and related conditions, such as noise-induced hearing loss, ototoxicity or autoimmune inner ear disease. While some systemic treatments exist, they generally exert adverse secondary effects and their efficacy is hampered by the blood-cochlear barrier that limits drug access to the inner ear. Hence, the new therapies that are being developed for hearing loss focus on strategies for direct drug delivery to the inner ear. The passive and active methods for local delivery can be categorized into two general groups: intratympanic or intracochlear. The intratympanic approach is a non-invasive method that preserves hearing and takes advantage of the permeability of the round window to gain access to the cochlea. However, this technique is limited by not knowing the dose of the drug that reaches the cochlea, (a handicap which might be overcome by the use of tagged drugs). While direct access to the inner ear by intracochlear administration avoids this problem, this method requires surgery. Currently, laboratory animals are being used to explore which therapeutic approaches are best suited to address this problem. These include cochleostomy and the insertion of devices that pump drugs into the inner ear without inducing cochlear damage. In this article, we review the different techniques under evaluation in animal models of deafness, and their potential use for drug delivery and treatment of human inner ear diseases.
助听器或人工耳蜗几乎是目前用于治疗感音神经性听力损失和相关疾病（如噪声性听力损失、耳毒性或自身免疫性内耳疾病）的唯一选择。虽然存在一些全身治疗方法，但它们通常会产生不良反应，并且由于血迷路屏障限制了药物进入内耳，其疗效受到阻碍。因此，目前正在开发的治疗听力损失的新疗法侧重于将药物直接递送到内耳的策略。局部给药的被动和主动方法可以分为两类：鼓室内或耳蜗内。鼓室内方法是非侵入性方法，可保留听力，并利用圆窗的通透性进入耳蜗。然而，这种技术受到不知道到达耳蜗的药物剂量的限制（可以通过使用标记药物来克服这个问题）。虽然通过耳蜗内给药直接进入内耳可以避免这个问题，但这种方法需要手术。目前，正在使用实验室动物来探索哪种治疗方法最适合解决这个问题。这些方法包括耳蜗造口术和插入将药物泵入内耳而不引起耳蜗损伤的装置。本文综述了在耳聋动物模型中评估的不同技术及其在药物输送和治疗人类内耳疾病方面的潜在用途。
