Many research groups and pharmaceutical companies worldwide are focusing on the use of microporation devices, and microneedles (MNs) are one of them. MNs are gaining significant interest in today's ...transdermal drug delivery research and development and a wide variety of strategies for the microfabrication of MNs have been reported. It was originally started with the microfabrication of silicon MNs and the technology was later extended towards the microfabrication of metal and polymeric MN arrays. In this chapter, we have described different microfabrication techniques of MN arrays for transdermal drug delivery applications. We have described in detail the design, fabrication and materials utilised in MN fabrication. Also, an account for optimisation of the MN design is given in order to address its effective application in transdermal drug delivery.
MNs, when used to puncture the skin, will by‐pass the stratum corneum and create transient aqueous transport pathways of micron dimensions and enhance the transdermal permeability. However, for ...effective performance of these MNs in drug delivery applications, irrespective of the type (hollow or solid), material, height and density of MNs, it is imperative that these needles penetrate into the skin with the greatest possible accuracy and reproducibility. But, due to the inherent elasticity and irregular surface of the skin, it remains a major challenge for reproducible MN arrays penetration. Therefore, in order to achieve uniform and reproducible MNs penetration into the skin, an external source of assistance is required such as an applicator device. Accordingly, this chapter deals with various innovative applicator designs developed and patented by different industries, and also by researchers from academia, in the context of effective application of MN arrays for transdermal drug delivery.
Microneedle-mediated Intradermal Delivery Morrow, Desmond I. J; Singh, Thakur Raghu Raj; Woolfson, A. David ...
Microneedle-mediated Transdermal and Intradermal Drug Delivery,
2012, 2012-02-03
Book Chapter
In this chapter, we describe the use of microneedle arrays for delivery to targets within the skin itself. Breaching the skin's stratum corneum barrier raises the possibility of administration of ...vaccines, gene vectors, antibodies, photosensitisers and even nanoparticles, all of which have at least their initial effect on populations of skin cells. Intradermal vaccine delivery, in particular, holds enormous potential for improved therapeutic outcomes for patients, particularly those in the developing world. Various vaccine‐delivery strategies have been employed and here we discuss each one in turn. We also describe how photodynamic therapy can be enhanced using microneedles, and explore the potential of intradermal nanoparticle deposition using microneedles.
Microporation of skin results in breaching the skin's stratum corneum barrier, thereby enhancing delivery of drugs of different physicochemical properties. However, application of microneedles (MNs) ...can be associated with the sensation of pain, erythema or both. Furthermore, by creating microchannels across the skin's stratum corneum, its barrier property is compromised, thus increasing the risk of invasion of exogenous materials (for example microorganisms), depending upon the MN dimensions. Additionally, the nature of material used in MN fabrication is also an integral component for its clinical application. In this chapter we discuss various clinical and safety parameters essential for widespread application of MNs.
Transdermal Delivery Applications Morrow, Desmond I. J; Singh, Thakur Raghu Raj; Woolfson, A. David ...
Microneedle-mediated Transdermal and Intradermal Drug Delivery,
2012, 2012-02-03
Book Chapter
To date, transdermal delivery has been restricted to a relatively small number of drugs with specific physicochemical properties. In this chapter, we examine the potential role of microneedle ...technology in broadening the range of compounds that can be delivered percutaneously. Particular attention is paid to reviewing how the physicochemical properties of a drug substance influence its penetration through microneedle‐induced micropores. In addition, we discuss the various microneedle systems that have been employed to deliver drugs across the skin. We also highlight the primary hurdles that must be overcome so that these relatively sophisticated drug delivery systems can become commercially available.
Microneedles: Current Status and Future Perspectives Morrow, Desmond I. J; Singh, Thakur Raghu Raj; Woolfson, A. David ...
Microneedle-mediated Transdermal and Intradermal Drug Delivery,
2012, 2012-02-03
Book Chapter
In this final chapter, we describe the use of microneedle arrays for emerging applications, such as drug delivery into the eye, extraction of blood or skin interstitial fluid for therapeutic drug ...monitoring purposes, delivery of active cosmaceutical ingredients and direct effects on skin. We also consider the activities of industry and look towards the future, with the focus on commercial and clinical application of microneedle technology and the barriers which may need to be overcome to make this a reality.
Transdermal Drug Delivery Morrow, Desmond I. J; Singh, Thakur Raghu Raj; Woolfson, A. David ...
Microneedle-mediated Transdermal and Intradermal Drug Delivery,
2012, 2012-02-03
Book Chapter
The skin is the largest single organ of the human body and acts as a barrier to the external environment. This chapter describes the detailed structure of the skin and explains the issues involved in ...using intact, healthy skin as a portal for systemic drug delivery. The stratum corneum, due to its unique and highly organised structure, is identified as the primary barrier to transdermal drug delivery, with passive drug diffusion along a concentration gradient being the primary method of permeation across the barrier. This, in turn, dictates the need for conventional transdermal drug delivery to employ drugs with sufficient lipophilicity to allow permeation via an intercellular pathway through the lipids of the stratum corneum. The alternative pathway, through skin appendages, is also described, along with its limitations as a major route for nonfacilitated transdermal delivery.
Given the advantages of transdermal delivery for the patient, there is a clear need to extend the utility of the transdermal route such that it is accessible for a wider range of pharmacologically active agents. Due to the limitations imposed by conventional transdermal systems, notably the restriction to lipophilic permeants, a range of facilitation technologies are described that may be used to overcome the skin barrier in cases where the required drug does not have ideal physicochemical properties for passive permeation through the skin barrier. Technologies considered include cryopneumatic and photopneumatic approaches, sonophoresis (low‐frequency ultrasound), iontophoresis, electroporation, jet injection and microneedles.
Intro Singh, Thakur Raghu Raj; Donnelly, Ryan F; Morrow, Desmond I. J ...
Microneedle-mediated Transdermal and Intradermal Drug Delivery,
2012
Book Chapter
Intro Singh, Thakur Raghu Raj; Donnelly, Ryan F; Morrow, Desmond I. J ...
Microneedle-Mediated Transdermal and Intradermal Drug Delivery,
2012
Book Chapter
