Microneedles for drug delivery: trends and progress

In recent years there has been a surge in the research and development of microneedles, a transdermal delivery system that combines the technology of transdermal patches and hypodermic needles. The needles are in the hundreds of micron length range and therefore allow relatively little or no pain. For example, biodegradable microneedles have been researched in the literature and have several advantages compared to solid or hollow microneedles, as they produce non-sharp waste and can be designed to allow rapid or slow release of drugs. However they also pose a disadvantage as successful insertion into the stratum corneum layer of the skin relies on sufficient mechanical strength of the biodegradable material. This review looks at the various technologies developed in microneedle research and shows the rapidly growing numbers of research papers and patent publications since the first invention of microneedles (using time series statistical analysis). This provides the research and industry communities a valuable synopsis of the trends and progress being made in this field

A compendium of current developments on polysaccharide and protein-based microneedles

Microneedles (MNs), i.e. minimally invasive three-dimensional microstructures that penetrate the stratum corneum inducing relatively little or no pain, have been studied as appealing therapeutic vehicles for transdermal drug delivery. Over the last years, the fabrication of MNs using biopolymers, such as polysaccharides and proteins, has sparked the imagination of scientists due to their recognized biocompatibility, biodegradability, ease of fabrication and sustainable character. Owing to their wide range of functional groups, polysaccharides and proteins enable the design and preparation of materials with tunable properties and functionalities. Therefore, these biopolymer-based MNs take a revolutionary step offering great potential not only in drug administration, but also in sensing and response to physiological stimuli. In this review, a critical and comprehensive overview of the polysaccharides and proteins employed in the design and engineering of MNs will be given. The strategies adopted for their preparation, their advantages and disadvantages will be also detailed. In addition, the potential and challenges of using these matrices to deliver drugs, vaccines and other molecules will be discussed. Finally, this appraisal ends with a perspective on the possibilities and challenges in research and development of polysaccharide and protein MNs, envisioning the future advances and clinical translation of these platforms as the next generation of drug delivery systems.publishe

A Review Article on Transdermal Drug Delivery System Based On- Microneedles

Every drug delivery system should work toward preserving the drug\u27s appropriate dose and facilitating its full metabolism within the body. Transdermal delivery of very large ionic and hydrophilic molecules is made possible by the microneedle array. Studies on the effectiveness of microneedles have been conducted extensively. Soon, the market for commercial microneedle-based goods will grow, and they may eventually have a major impact on clinical medicine. This article provides an overview of microneedles, discussing their history, many varieties, current state, potential applications, and recent technological developments

A COMPREHENSIVE REVIEW ON MICRONEEDLES - AN ARCHETYPE SWING IN TRANSDERMAL DRUG DELIVERY

Transdermal drug delivery is the non-invasive delivery of medications through the skin surface into the systemic circulation. The advantage of transdermal drug delivery system is that it is painless technique of administration of drugs. The advantage of transdermal drug delivery system is that it is painless technique of administration of drugs. Transdermal drug delivery system can improve the therapeutic efficacy and safety of the drugs because drug delivered through the skin at a predetermined and controlled rate. Due to the various biomedical benefits, it has attracted many researches. The barrier nature of stratumcorneum poses a danger to the drug delivery. By using microneedles, a pathway into the human body can be recognized which allow transportation of macromolecular drugs such as insulin or vaccine. These microneedles only penetrate outer layers of the skin, exterior sufficient not to reach the nerve receptors of the deeper skin. Thus the microneedles supplement is supposed painless and reduces the infection and injuries. Researches from the past few years showed that microneedles have emerged as a novel carrier and considered to be effective for safe and improved delivery of the different drugs. Microneedles development is created a new pathway in the drug delivery field. This review focus on new advances in transdermal drug delivery system using various carriers emphasizing mostly on the potential role of microneedles as transdermal system

3D printed microneedle patches using stereolithography (SLA) for intradermal insulin delivery

3D printed microneedle arrays were fabricated using a biocompatible resin through stereolithography (SLA) for transdermal insulin delivery. Microneedles were built by polymerising consecutive layers of a photopolymeric resin. Thin layers of insulin and sugar alcohol or disaccharide carriers were formed on the needle surface by inkjet printing. The optimization of the printing process resulted in superior skin penetration capacity of the 3D printed microneedles compared to metal arrays with minimum applied forces varying within the range of 2 to 5 N. Micro-CT analysis showed strong adhesion of the coated films on the microneedle surface even after penetration to the skin. In vivo animal trials revealed fast insulin action with excellent hypoglycaemia control and lower glucose levels achieved within 60 min, combined with steady state plasma glucose over 4 h compared to subcutaneous injections

Transdermal Microneedles for Insulin Delivery

Diabetes is a chronic metabolic disease that occurs when there is a deficiency in the production of insulin by the pancreas or when the body cannot effectively use the insulin it produces. Therefore, the treatment of diabetes aims to control the levels of glucose in the blood, which involves many different approaches, including insulin therapy many times. To date, even though many strategies have been proposed as alternative administration routes for insulin, subcutaneous injections still the most common administration route. To overcome the disadvantages imposed by the daily subcutaneous injections of insulin and to increase patient compliance, this thesis aimed to develop stable coated microneedles for rapid transdermal delivery of insulin. For that, polymeric microneedles made of a biocompatible resin class I were developed using 3D printing technology and studied along with a commercial metallic microneedle. The penetration studies showed that the 3D printed MNs presented superior penetration capacity compared to the metallic microneedles. To apply specific doses of insulin on the microneedles, an Inkjet printing technology was used. The SEM revealed the formation of fine layers on the microneedles without loss of insulin during the coating process. Moreover, Micro-CT showed that the films stayed onto the MNs surfaces during the piercing. In order to address the challenges with insulin instability, different polymers and sugars were used as drug carriers to preserve insulin integrity during the coating process as well as to form uniform coating layers and facilitate rapid release rates. Circular dichroism and Raman spectroscopy demonstrated that most of the carriers maintained the secondary structure of insulin in its native form in the films. Moreover, X-ray diffraction analysis revealed that the insulin-carriers tended to originate amorphous films. The release studies using Franz cell diffusion showed that insulin is quickly released from the coated microneedles within 30 min. Furthermore, the animal studies showed that the coated 3D printed microneedles promoted a similar initial profile release to the SC injections, followed by a more sustained release pattern for all tested insulins (bovine, aspart and glargine)

REVIEW ON TRANSDERMAL MICRONEEDLE-BASED DRUG DELIVERY

Drug delivery research extensively studies methods to transport proteins, deoxyribonucleic acid (DNA), genes, antibodies, and vaccines efficiently and safely to human bodies in recent years. This review comprehensively covers the developments in microneedle-based drug delivery, their configurations, design, fabrication, and operation. The factors surrounding the mechanical strength of microneedle-based transdermal patches (MNTP's) have also been reviewed. MNTP's can eliminate limitations of conventional drug delivery systems. Microneedle-based transdermal delivery approach will offer a self-management, patient-friendly, and efficient administration route for drug delivery

Advances in transdermal insulin delivery

Insulin therapy is necessary to regulate blood glucose levels for people with type 1 diabetes and commonly used in advanced type 2 diabetes. Although subcutaneous insulin administration via hypodermic injection or pump-mediated infusion is the standard route of insulin delivery, it may be associated with pain, needle phobia, and decreased adherence, as well as the risk of infection. Therefore, transdermal insulin delivery has been widely investigated as an attractive alternative to subcutaneous approaches for diabetes management in recent years. Transdermal systems designed to prevent insulin degradation and offer controlled, sustained release of insulin may be desirable for patients and lead to increased adherence and glycemic outcomes. A challenge for transdermal insulin delivery is the inefficient passive insulin absorption through the skin due to the large molecular weight of the protein drug. In this review, we focus on the different transdermal insulin delivery techniques and their respective advantages and limitations, including chemical enhancers-promoted, electrically enhanced, mechanical force-triggered, and microneedle-assisted methods

The clinical and translational prospects of microneedle devices, with a focus on insulin therapy for diabetes mellitus as a case study

Microneedles have the clinical advantage of being able to deliver complex drugs across the skin in a convenient and comfortable manner yet haven’t successfully transitioned to medical practice. Diabetes mellitus is a complicated disease, which is commonly treated with multiple daily insulin injections, contributing to poor treatment adherence. Firstly, this review determines the clinical prospect of microneedles, alongside considerations that ought to be addressed before microneedle technology can be translated from bench to bedside. Thereafter, we use diabetes as a case study to consider how microneedle-based-technology may be successfully harnessed. Here, publications referring to insulin microneedles were evaluated to understand whether insertion efficiency, angle of insertion, successful dose delivery, dose adjustability, material biocompatibility and therapeutic stability are being addressed in early stage research. Moreover, over 3,000 patents from 1970-2019 were reviewed with the search term ‘“microneedle” AND “insulin”’ to understand the current status of the field. In conclusion, the reporting of early stage microneedle research demonstrated a lack of consistency relating to the translational factors addressed. Additionally, a more rational design, based on a patient-centred approach is required before microneedle-based delivery systems can be used to revolutionise the lives of people living with diabetes following regulatory approval