title: Potential of microneedles in enhancing delivery of photosensitising agents for photodynamic therapy.
abstract: Photodynamic therapy can be used in the treatment of pre-malignant and malignant diseases. It offers advantages over other therapies currently used in the treatment of skin lesions including avoidance of damage to surrounding tissue and minimal or no scarring. Unfortunately, systemic delivery of photosensitising agents can result in adverse effects, such as prolonged cutaneous photosensitivity; while topical administration lacks efficacy in the clearance of deeper skin lesions and those with a thick overlying keratotic layer. Therefore, enhancement of conventional photosensitiser delivery is desired. However, the physicochemical properties of photosensitising agents, such as extreme hydrophilicity or lipophilicity and large molecular weights make this challenging. This paper reviews the potential of microneedles as a viable method to overcome these delivery-limiting physicochemical characteristics and discusses the current benefits and limitations of solid, dissolving and hydrogel-forming microneedles. Clinical studies in which microneedles have successfully improved photodynamic therapy are also discussed, along with benefits which microneedles offer, such as precise photosensitiser localisation, painless application and reduction in waiting times between photosensitiser administration and irradiation highlighted.
authors.affiliation: School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK.
authors.forename: Mary-Carmel
authors.initials: MC
authors.lastname: Kearney
authors.affiliation: School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Brown
authors.affiliation: School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK.
authors.forename: Maelíosa T C
authors.initials: MT
authors.lastname: McCrudden
authors.affiliation: School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK.
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Brady
authors.affiliation: School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK. Electronic address: r.donnelly@qub.ac.uk.
authors.forename: Ryan F
authors.initials: RF
authors.lastname: Donnelly
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D044085:Microfluidics / Q000295:instrumentation*; D008845:Microinjections / Q000295:instrumentation*; D008904:Miniaturization; D009339:Needles; D010778:Photochemotherapy / Q000295:instrumentation*; D017319:Photosensitizing Agents / Q000008:administration & dosage* / Q000627:therapeutic use*
chemical_list: D017319:Photosensitizing Agents
keywords: Microneedle; Photodynamic therapy; Photosensitiser; Preformed photosensitisers