Microneedle Mediated Transdermal Delivery of Protein, Peptide and Antibody Based Therapeutics: Current Status and Future Considerations
The success of protein, peptide and antibody based therapies is evident – the biopharmaceuticals market is predicted to reach $388 billion by 2024, and more than half of the current top 20 blockbuster drugs are biopharmaceuticals. However, the intrinsic properties of biopharmaceuticals has restricted the routes available for successful drug delivery. While providing 100% bioavailability, the intravenous route is often associated with pain and needle phobia from a patient perspective, which may translate as a reluctance to receive necessary treatment. Several non-invasive strategies have since emerged to overcome these limitations. One such strategy involves the use of microneedles (MNs), which are able to painlessly penetrate the stratum corneum barrier to dramatically increase transdermal drug delivery of numerous drugs. This review reports the wealth of studies that aim to enhance transdermal delivery of biopharmaceutics using MNs. The true potential of MNs as a drug delivery device for biopharmaceuticals will not only rely on acceptance from prescribers, patients and the regulatory authorities, but the ability to upscale MN manufacture in a cost-effective manner and the long term safety of MN application. Thus, the current barriers to clinical translation of MNs, and how these barriers may be overcome are also discussed.
Microneedle (MN) arrays consist of multiple micro-projections assembled on one side of a supporting base, ranging in height from 25 to 900 μm. MN arrays effectively bypass the stratum corneum barrier by creating temporary microscopic aqueous channels within the epidermis, through which drug molecules can diffuse into the dense microcirculation, present in the dermis. MNs were first conceptualised by Gerstel and Place in 1971, but were not practically realised until 1998, when manufacturing capabilities and microfabrication techniques became more advanced. Today, MN technology has developed further and they are traditionally placed in five different categories: solid, coated, hollow, dissolving and hydrogel-forming. (Pharm Res. 2020; 37(6): 117.)