Transdermal Drug Delivery Adhesion as a Critical Parameter

Abstract

Transdermal drug delivery system (TDDS), also known as "patches", are the dosage forms designed to deliver a therapeutically effective amount of drug across a patient's skin. The adhesive of the transdermal drug delivery system is very crucial to the safety, efficacy and quality of the product. Recently, it has been recognized that the skin can also serve as the port of administration for systemically active drugs. The drugs applied topically are first absorbed into the blood stream and then are transported to the target tissues. Now, it is becoming evident that the benefits of intra venous infusion can be closely duplicated by using skin as the port of drug administration to provide continuous transdermal drug infusion into the systemic circulation. One of the objectives of TDDS is the maintenance of blood concentration of drug at therapeutic level by means of controlled permeation throughout the skin during a long period of time and using only one administration. The drug input can be terminated at any point of time by just removing the patch. Rate of drug release from the TDDS is normally much greater than the amount that the skin can possibly absorb. Hence, even if there is a variation in skin permeability, a constant rate of drug input into the circulation is achieved. This article provides an overview of type of transdermal systems, role of adhesion, possible adhesion failures and the measurement of adhesion. In vitro techniques like peel adhesion, tack and shear strength are discussed. Adhesion needs to be a critical parameter for designing a transdermal drug delivery system in order to provide good quality and efficacy to the patient. This review also covers a brief outline of various components of a patch, their advantages, when the patch should be used and when their use should be avoided.

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“…A sufficient quantity (10mg) of drug dissolved in each investigated solvent at room temperature. The solubility was only determined by visual inspection 9 .…”

Extensive subcutaneous haematoma associated with transdermal analgesic patch in a haemophilia A patient with inhibitor

“…Fentanyl transdermal patches are commonly used in the treatment of chronic pain [1]. Such transdermal drug systems allow for the delivery of active ingredients via the skin over a sustained period of time and are suited for situations where persistent symptoms are experienced [2]. Excessive bleeding related to the use of transdermal patches in people living with haemophilia has not been reported previously.…”

“…This care is often carried out by expert multi-disciplinary teams based in tertiary level haemophilia treatment centres (HTCs) [1]. However, as the life expectancy of men with haemophilia increases [2], attention must shift to the challenges posed by ageing in this population, including the prevention and management of age-related comorbidities [2,3]. Collaboration with primary care clinicians is essential in addressing these challenges [3,4], but the question remains, do men with haemophilia move beyond tertiary HTCs and engage with clinicians at the primary care level to discuss health promotion and illness prevention?…”

“…For men with haemophilia, many of the same barriers may be relevant, but additional factors, unique to the experience of haemophilia, may also come into play. In particular, the lifelong and comprehensive clinical management offered by HTCs may reduce the perceived need to access primary care [2,5]. Evidence indicates a level of concern among men with haemophilia, that clinicians from other disciplines may not understand the clinical complexities of bleeding disorders [4].…”