Safety evaluation of 3-month effects of microneedle patches prepared from hyaluronic acid in mice

Dissolving Microneedles Patch: A Promising Approach for Advancing Transdermal Delivery of Antischizophrenic Drug

OBJECTIVE

Microneedles (MNs) are minimally invasive transdermal drug delivery systems capable of penetrating the stratum corneum to overcome the barrier properties. The primary objective of this research was to prepare dissolving microneedle patches (DMNP) loaded with quetiapine (QTP).

METHODS

DMNP were fabricated employing the solvent casting technique, utilizing various polymer feed ratios including polyvinyl alcohol (PVA), polyvinylpyrrolidone K30 (PVP-K30), and polylactide-co-glycolide (PLGA) polymers. The loaded DMNP with QTP underwent a comprehensive characterization process encompassing assessments for compatibility, thickness, insertion potential, morphology, thermal behavior, X-ray diffraction, ex-vivo permeation, skin irritation, and histopathological changes.

RESULTS

FTIR studies confirmed the compatibility of QTP with the microneedle patch composites. The thickness of the drug-loaded DMNP ranged from 0.67 mm to 0.97 mm. These microneedles exhibited an impressive penetration depth of 480 μm, with over 80% of the needles maintaining their original shape after piercing Parafilm-M. SEM analysis of the optimized DMNP-2 revealed the formation of sharp-tipped and uniformly surfaced needles, measuring 570 μm in length. Remarkably, the microneedles did not elicit any signs of irritation upon application of the prepared DMNP. The DMNP-2 showcased an impressive cumulative ex-vivo permeation of QTP, reaching 17.82 µg/cm2/hr. Additionally, histopathological assessment of vital organs in rabbits attested to the safety profile of the formulated microneedle patches.

CONCLUSIONS

In conclusion, the developed microneedle patch represents a promising strategy for enhancing the transdermal delivery of QTP. This innovative approach has the potential to increase patient compliance, offering a more efficient and patient-friendly method of administering QTP.

Microneedles Based on a Biodegradable Polymer-Hyaluronic Acid

Transdermal transport can be challenging due to the difficulty in diffusing active substances through the outermost layer of the epidermis, as the primary function of the skin is to protect against the entry of exogenous compounds into the body. In addition, penetration of the epidermis for substances hydrophilic in nature and particles larger than 500 Da is highly limited due to the physiological properties and non-polar nature of its outermost layer, namely the stratum corneum. A solution to this problem can be the use of microneedles, which "bypass" the problematic epidermal layer by dispensing the active substance directly into the deeper layers of the skin. Microneedles can be obtained with various materials and come in different types. Of special interest are carriers based on biodegradable and biocompatible polymers, such as polysaccharides. Therefore, this paper reviews the latest literature on methods to obtain hyaluronic acid-based microneedles. It focuses on the current advancements in this field and consequently provides an opportunity to guide future research in this area.

Fabrication and characterization of coated microneedle patches based on PEGDA for transdermal administration of metformin

Type 2 diabetes is one of the major challenges that the world is facing today. However, metformin (MET) as most type 2 diabetics' first-line oral hypoglycemic drug may cause serious side effects such as gastrointestinal irritation and nausea which reduce the patients' medication compliance. Therefore, the aim of the study was to design a safe and effective self-treatment device for the delivery of MET. Here, a kind of coated microneedle (MN) patches based on poly(ethylene glycol)diacrylate (PEGDA) were prepared by a two-step casting method and photopolymerization process for transdermal administration of MET. The needles wrapped with drug-loaded hyaluronic acid (HA) coating showed promising mechanical properties and drug delivery ability that allowed them to penetrate the skin barrier for rapid drug delivery, and they had no skin irritancy. The in vivo experiment of type 2 diabetic rats showed a satisfying hypoglycemic effect of the coated MN patches. The study shows that the prepared MN patches will be a potential method for the treatment of type 2 diabetes in the future.

Fast dissolving microneedle patch for pronounced systemic delivery of an antihyperlipidemic drug

Fast dissolving microneedles (F-dMN) are quite a novel approach delivering specific drug molecules directly into the bloodstream, bypassing the first-pass effect. The present study reported an F-dMN patch to enhance systemic delivery of simvastatin in a patient-friendly manner. The F-dMN patch was developed using polyvinyl pyrrolidone and polyvinyl alcohol and characterized using light microscopy, SEM, XRD, FTIR, mechanical strength, drug content (%), an ex-vivo penetration study, an ex-vivo drug release study, a skin irritation test, and a pharmacokinetics study. The optimized F-dMN patch exhibited excellent elongation of 35.17%, good tensile strength of 9.68  MPa, an appropriate moisture content of 5.65%, and good penetrability up to 560 µm. Moreover, it showed 93.4% of the drug content within the needles and 81.75% in-vitro release. Histopathological findings and a skin irritation study proved that the F-dMN patch was biocompatible and did not cause any sort of irritation on animal skin. Pharmacokinetic parameters of F-dMN patches were improved (Cmax 6.974 µg/ml, tmax 1 hr and AUC 19. 518 µg.h/ml) as compared to tablet Simva 20 mg solution (Cmax 2.485 µg/ml, tmax 1.4 hr and AUC 11.199 µg.h/ml), thus confirming bioavailability enhancement. Moreover, stability studies confirmed the stability of the developed F-dMN patch, as investigated by axial needle fracture force and drug content.

Progress in the preparation and evaluation of glucose-sensitive microneedle systems and their blood glucose regulation

Glucose-sensitive microneedle systems (GSMSs) as an intelligent strategy for treating diabetes can well solve the problems of puncture pain, hypoglycemia, skin damage, and complications caused by the subcutaneous injection of insulin. According to the various functions of each component, herein, therapeutic GSMSs are reviewed based on three parts (glucose-sensitive models, diabetes medications, and microneedle body). Moreover, the characteristics, benefits, and drawbacks of three types of typical glucose-sensitive models (phenylboronic acid based polymer, glucose oxidase, and concanavalin A) and their drug delivery models are reviewed. In particular, phenylboronic acid-based GSMSs can provide a long-acting drug dose and controlled release rate for the treatment of diabetes. Moreover, their painless, minimally invasive puncture also greatly improves patient compliance, treatment safety, and potential application prospects.

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.