A Comprehensive Review of Microneedles: Types, Materials, Processes, Characterizations and Applications

Abstract

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.

Microneedle-Based Natural Polysaccharide for Drug Delivery Systems (DDS): Progress and Challenges

“…Each type of microneedle has its own benefits and limitation for delivery of the drug at the target site. However, some researchers classified microneedles based on the fabrication method [73]. As the characteristics of microneedles vary by type, an appropriate microneedle design should be selected based on drug dose, the onset of action, delivery period, delivery efficiency, packaging, cutting waste, and patch wear time (Tables 1 and 2).…”

“…Each type of mi for delivery of the drug at the target site. Ho dles based on the fabrication method [73]. A type, an appropriate microneedle design sho of action, delivery period, delivery efficienc time (Tables 1 and 2).…”

Potential of Microneedle Systems for COVID-19 Vaccination: Current Trends and Challenges

“…Each study has been undertaken with the aim of providing a formulation with optimum values for Young’s modulus, Poisson’s ratio, ultimate tensile stress, dissolution kinetics, and polymer adsorption rate. Moreover, there are a good number of articles (e.g., [ 47 , 222 , 315 , 316 , 317 ]) that discuss the varied types of materials usually used to fabricate MNs.…”

Recent Advances in Polymer Microneedles for Drug Transdermal Delivery: Design Strategies and Applications

“…Moreover, for long‐term medication, the oral administration will impact the vital organs, such as stomach, liver, and kidneys. [ 5–7 ] In addition, some patients often forget to take medicines, or stop taking medicines when their symptoms improve, which reduces the compliance of patients with oral medicines. The injection route mainly includes intramuscular, subcutaneous, intravenous, and intradermal injection.…”