Microneedles as an alternative technology for transdermal drug delivery systems: a patent review.

Introduction: The most conventional drug delivery systems exist with limitations such as drug degradation, toxicity and low bioavailability. Also, hypodermic injections can cause pain, compromising patient compliance. Due to this, transdermal drug delivery systems can minimize several problems associated with conventional drug delivery. The development of microneedle arrays is an approach which allows drug delivery through the skin by improving safety, efficacy, and bioavailability. Hence, several studies have been searching for new ways of treatment using microneedle devices for transdermal drug delivery.Areas covered: All patents were analyzed from European Patent Office and World Intellectual Property Organization databases that reported microneedle arrays using the combined keywords 'microneedle' or 'microneedles' and 'drug delivery systems'. A total of 233 patents were analyzed, out of which 47 selected were microneedle devices for clinical applications.Expert opinion: In past years, there has been a crescent of advances in the development of microneedles as a drug delivery system by researchers and pharmaceutical companies. The authors observed patents related to manufacture of dissolving, hydrogel-forming, solid, hollow, and coated microneedles for ocular and transdermal drug delivery. Finally, the authors noticed patents about new microneedle technologies with potential therapeutic application in several clinical conditions confirmed in clinical tests.