Recent approaches for enhancing the performance of dissolving microneedles in drug delivery applications

Dissolving microneedles (dMNs) are promising versatile drug delivery systems for the transdermal delivery of numerous drugs, enabling their use in a wide range of biomedical and pharmaceutical applications. Being made of water-soluble polymers, dMNs own several advantages, including fast dissolution and short application time which enhance patients’ compliance and minimize the damage to skin tissue. Moreover, they possess no biohazard risk as they leave no sharp waste behind.

For these reasons, the research on dMNs has increased dramatically in recent years. The formulation of successful dMNs requires a well-defined pre-set design, considering the goal and the payloads that will be used. Every aspect of formulation as patch design, needles geometry, polymer composition, method of formation and payloads, has a direct effect on the mechanical properties of the MNs, affecting their administration and efficacy. Thus, there is the need to understand how each factor affects the final formulation and how to optimize each MN. Taking this into consideration, this review serves as a guide for dMN formulation, discussing the different setbacks of each step and possible strategies to overcome them, improving their administration, and enhancing the loading of various molecules and their controlled release.

Table 1. Common polymers for the preparation of dissolving MNs.^a

Polymer	Other compositions	Loaded bioactive agent	MNs application	Ref.
HA		Magnesium ascorbyl phosphate		[30]
		Methotrexate	Treatment of psoriasis	[31]
	MN-combined with bacterial nanocellulose as the back layer.	Rutin (model drug)		[32]
		Green tea extract	Wound healing	[33]
		Adenosine	Improve skin wrinkles, dermal density, and elasticity	[34]
	Sodium hyaluronate/ composite MNs chitosan	Ovalbumin (model antigen)	Intradermal immunization	[35]
	MNs containing curcumin-loaded micelles	Curcumin		[36]
		Insulin	Diabetes	[37]
	MNs loaded with near-infrared responsive PEGylated gold nanorod	Doxorubicin	Human epidermoid cancer therapy	[38]
		5-Aminolevulinic Acid	Photodynamic therapy of superficial tumors	[39]
		Sumatriptan Succinate	Migraine	[40]
		Gentamicin	Neonatal sepsis	[41]
	Alginate and hyaluronate	Insulin	Diabetes	[42]
		Insulin	Diabetes	[43]
		IgG	Intradermal protein delivery	[44]
PVP	Copolymer polyvinylpyrrolidone-co-methacrylic acid (PVP-MAA)	Allergen extracts	Skin allergy test	[45]
		mRNA		[46]
		Sinomenine hydrochloride	Anti-inflammatory	[47]
		Fluorescein sodium and fluorescein isothiocyanate–dextrans (model drugs)	Intraocular drug delivery	[16]
	Chitosan nanoparticles-loaded MNs	A model antigen, ovalbumin (OVA), and an adjuvant, CpG oligodeoxynucleotides (CpG).		[48]
Cellulose derivatives	CMC	Ovalbumin	Vaccination	[49]
	CMC	Lidocaine	Anesthesia	[50]
	CMC /powder-carrying MNs	Finasteride	Androgenetic alopecia	[51]
	HPC	Cyclosporin A		[52]
	HPMC/PVP	Alpha-Arbutin		[53]
Chitosan		Bovine serum albumin	Transdermal Delivery of Macromolecules	[54]
		Vascular endothelial growth factor (VEGF)	Wound healing	[55]
	Chitosan MNs and a poly(l-lactide-co-d,l-lactide) (PLA) supporting array	Ovalbumin	Vaccination	[56]
	Thiolated chitosan MNs	Tacrolimus	Immunosuppression	[57]
		Meloxicam	Pain management in cattle	[58]
		Ovalbumin	Vaccination	[59]
		Luteinizing Hormone-releasing Hormone	Androgen Deprivation Therapy for lethal prostate cancer	[60]
Alginate	Alginate and maltose	Insulin	Diabetes	[61]
		Bovine Serum Albumin		[62]
	Glucose-responsive gold nanocluster-loaded MNs	Insulin	Diabetes	[63]
silk fibroin		Insulin	Diabetes	[64]
		Chemotherapeutic agents (thrombin and temozolomide) and targeted drug (bevacizumab)		[65]
		Influenza vaccine	Vaccination	[66]
PVA		Doxorubicin	Cancer	[67]
	PVA/PVP	Bovine serum albumin	Macromolecules delivery	[68]
	PVA/PVP	Insulin	Diabetes	[69]
	Cholecalciferol nanosuspension-loaded MNs (PVA or PVP)	Cholecalciferol	Loading of hydrophobic drug	[70]
	PVA/maltose microneedle	Sinomenine hydrochloride	Rheumatoid arthritis	[71]

Download the full study as PDF here: Recent approaches for enhancing the performance of dissolving microneedles in drug delivery applications

or read it here

Tomás Bauleth-Ramos, Nesma El-Sayed, Flavia Fontana, Maria Lobita, Mohammad-Ali Shahbazi, Hélder A. Santos, Recent approaches for enhancing the performance of dissolving microneedles in drug delivery applications, Materials Today, 2023, ISSN 1369-7021,
https://doi.org/10.1016/j.mattod.2022.12.007.

See also two other interesting artices on microneedles published lately:

excipients formulation