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.

Development of morin/hydroxypropyl-ß-cyclodextrin inclusion complex: Enhancement of bioavailability, antihyperalgesic and anti-inflammatory effects.

Morin is a flavonoid has been reported with several pharmacological effects such as, antioxidant, anti-inflammatory, anticancer, antidiabetic, etc. However, morin has low solubility in water, which decreases the bioavailability and limits its clinical application. In this way, to improve the pharmaceutical properties, morin was complexed in hydroxypropyl-ß-cyclodextrin (HP-ß-CD) and its oral bioavailability and anti-inflammatory effects were evaluated. Initially, a phase solubility study was performed, which showed that HP-ß-CD would be the better cyclodextrin for the formation of complexes with morin. The morin/HP-ß-CD inclusion complex (1:1) was prepared by freeze-drying method. The sample obtained was characterized by DSC, FTIR, PXRD, SEM and 1H NMR techniques, evidencing the formation of morin/HP-ß-CD inclusion complex. In addition, complexation efficiency (98.3%) and loading content (17.63%), determined by HPLC demonstrated that morin was efficiently complexed in HP-ß-CD. In vitro dissolution study confirmed that morin/HP-ß-CD inclusion complex increased the solubility and dissolution rate of morin. The oral bioavailability of the morin/HP-ß-CD complex and free morin were evaluated through a pharmacokinetic study in rat plasma. The oral bioavailability of morin complexed with HP-ß-CD was increased by 4.20 times compared with the free morin. Hyperalgesia induced by carrageenan and carrageenan-induced pleurisy were carried out in mice to evaluate the antihyperalgesic and anti-inflammatory activities of free morin and inclusion complex. Morin/HP-ß-CD inclusion complex showed antihyperalgesic effect in inflammatory pain model and anti-inflammatory effect decreasing leukocyte migration and TNF-α levels at a lower dose than free morin. Therefore, the morin/HP-ß-CD inclusion complex improved the solubility, dissolution rate, oral bioavailability, antihyperalgesic and anti-inflammatory effects of morin. In this way, the morin/HP-ß-CD inclusion complex exhibits potential for development of new pharmaceutical product for future clinical applications.