Search Results (4)

Microneedle (MN) technologies have emerged as a groundbreaking platform for transdermal and intradermal drug delivery, offering a minimally invasive alternative to oral and parenteral routes. Unlike passive transdermal systems, MNs allow the permeation of hydrophilic macromolecules, such as peptides, proteins, and vaccines, by penetrating the stratum corneum barrier without causing pain or tissue damage, unlike hypodermic needles. Recent advances in materials science, microfabrication, and biomedical engineering have enabled the development of various MN types, including solid, coated, dissolving, hollow, hydrogel-forming, and hybrid designs. Each type has unique mechanisms, fabrication techniques, and pharmacokinetic profiles, providing customized solutions for a range of therapeutic applications. The integration of 3D printing technologies and stimulus-responsive polymers into MN systems has enabled patches that combine drug delivery with real-time physiological sensing. Over the years, MN applications have grown beyond vaccines to include the delivery of insulin, anticancer agents, contraceptives, and various cosmeceutical ingredients, highlighting the versatility of this platform. Despite this progress, broader clinical and commercial adoption is still limited by issues such as scalable and reliable manufacturing, patient acceptance, and meeting regulatory expectations. Overcoming these barriers will require coordinated efforts across engineering, clinical research, and regulatory science. This review thoroughly summarizes MN technologies, beginning with their classification and drug-delivery mechanisms, and then explores innovations, therapeutic uses, and translational challenges. It concludes with a critical analysis of clinical case studies and a future outlook for global healthcare. By comparing technological progress with regulatory and commercial hurdles, this article highlights the opportunities and limitations of MN systems as a next-generation drug-delivery platform. Full article

This review systematically outlines recent advances in long-acting microneedle-based transdermal drug delivery systems. It begins by introducing the fundamental principles of microneedles (MNs) as a minimally invasive technology and categorizes them by delivery mechanism into solid, coated, dissolving, hollow, hydrogel-forming, and biodegradable types. The review then discusses the design strategies and material platforms engineered for sustained drug release. A key focus is on biodegradable synthetic polymers, such as polylactic acid (PLA), poly (lactic-co-glycolic acid) (PLGA), and polycaprolactone (PCL), and natural polymers like silk fibroin (SF) and chitosan (CS), which enable prolonged drug release through their tunable degradation rates. Furthermore, it describes the incorporation of advanced drug carriers, including liposomes and polymeric nanoparticles/microparticles, into MNs to further extend release duration and enhance drug-loading capacity. Finally, the major challenges for clinical translation are addressed, including ensuring batch-to-batch consistency in manufacturing, maintaining sterility, and the necessity for more comprehensive validation of long-term in vivo efficacy and safety. Full article

Transdermal drug delivery (TDD), which enables targeted delivery with microdosing possibilities, has seen much progress in the past few years. This allows medical professionals to create bespoke treatment regimens and improve drug adherence through real-time monitoring. TDD also increases the effectiveness of the drugs in much smaller quantities. The use of polymers in the drug delivery field is on the rise owing to their low cost, scalability and ease of manufacture along with drug and bio-compatibility. In this work, we present the design, development and characterization of a polymer-based TDD platform fabricated using additive manufacturing technologies. The system consists of a polymer based micropump integrated with a drug reservoir fabricated by 3D printing and a polymer hollow microneedle array fabricated using photolithography. To the best of our knowledge, we present the fabrication and characterization of a 3D-printed piezoelectrically actuated non-planar valveless micropump and reservoir integrated with a polymer hollow microneedle array for the first time. The integrated system is capable of delivering water at a maximum flow rate of 1.03 mL/min and shows a maximum backpressure of 1.37 kPa while consuming only 400 mW. The system has the least number of moving parts. It can be easily fabricated using additive manufacturing technologies, and it is found to be suitable for drug delivery applications. Full article

Drug delivery through the skin offers many advantages such as avoidance of hepatic first-pass metabolism, maintenance of steady plasma concentration, safety, and compliance over oral or parenteral pathways. However, the biggest challenge for transdermal delivery is that only a limited number of potent drugs with ideal physicochemical properties can passively diffuse and intercellularly permeate through skin barriers and achieve therapeutic concentration by this route. Significant efforts have been made toward the development of approaches to enhance transdermal permeation of the drugs. Among them, microneedles represent one of the microscale physical enhancement methods that greatly expand the spectrum of drugs for transdermal and intradermal delivery. Microneedles typically measure 0.1–1 mm in length. In this review, microneedle materials, fabrication routes, characterization techniques, and applications for transdermal delivery are discussed. A variety of materials such as silicon, stainless steel, and polymers have been used to fabricate solid, coated, hollow, or dissolvable microneedles. Their implications for transdermal drug delivery have been discussed extensively. However, there remain challenges with sustained delivery, efficacy, cost-effective fabrication, and large-scale manufacturing. This review discusses different modes of characterization and the gaps in manufacturing technologies associated with microneedles. This review also discusses their potential impact on drug delivery, vaccine delivery, disease diagnostic, and cosmetics applications. Full article