A Review on Microneedle-Based Transdermal Drug Delivery Systems

Microneedles are minimally invasive transdermal drug delivery systems consisting of microscopic projections that penetrate the stratum corneum to facilitate drug administration. These devices range from 25-2000 μm in length and are fabricated using various materials including metals, polymers, and biodegradable substances. The fundamental classifications encompass solid microneedles that create temporary channels, coated microneedles carrying drugs on their surface, hollow microneedles enabling direct fluid transport, and dissolving microneedles that release encapsulated drugs upon degradation. The fabrication processes involve techniques such as photolithography, micromolding, and 3D printing, with each method optimized for specific microneedle designs and materials. Therapeutic applications extend across multiple domains, particularly in treating superficial cancers through various modalities including chemotherapy, photodynamic therapy, and immunotherapy. For cancer treatment, microneedles enable localized drug delivery, reducing systemic toxicity while maintaining therapeutic efficacy. In managing inflammatory skin conditions like psoriasis and atopic dermatitis, microneedles facilitate targeted delivery of anti-inflammatory agents and biologics directly to affected areas. The technology demonstrates significant potential in wound healing, particularly for diabetic and infected wounds, by delivering growth factors and antimicrobial agents precisely to the wound bed. Additional applications include aesthetic dermatology, vaccine delivery, and diagnostic sampling. Current research focuses on developing smart materials, improving drug loading capacity, and enhancing long-term stability while maintaining cost-effectiveness and patient compliance