Preparation and characterization of flexible furosemide-loaded biodegradable microneedles for intradermal drug delivery

Abstract

Transdermal drug delivery systems are a useful and minimally invasive alternative to other drug administration routes. Biodegradable polymeric microneedles (MNs) are widely used in controlled‐release drug delivery due to their...

Hydrogel Microneedles with Programmed Mesophase Transitions for Controlled Drug Delivery

“…The insertion test was performed using eight stacked layers of Parafilm (∼140 μm each) as a skin simulant to investigate the penetration ability of the MN arrays as well as the insertion depth. − This skin-simulant model was developed and validated by Larrañeta et al, showing that the insertion profiles obtained are consistent with the insertion depths obtained with optical coherence tomography (OCT), and the force that was used in this test gave insertion profiles equivalent to those obtained using neonatal pig skin . Briefly, the obtained MNs were inserted manually into the Parafilm layers, held for 30 s, and then removed.…”

“…To further elucidate the mechanical properties and insertion capability of DEX-loaded MNs, the MNs were subjected to penetration testing using ex vivo chicken skin (Figure A). Chicken skin has been employed as a suitable simulant for human skin by numerous researchers to characterize microneedle arrays. ,− Skin penetration is characterized as a series of sequential small penetrations where the MNs gradually tear the skin, while the force increases until it reaches a plateau followed by more rapid increase, indicating successful skin piercing. − Figure B shows the force–displacement curve in which the force was normalized by the number of needles (force per a single needle) in each MN array. At the insertion point, an abrupt change in slope in the form of a small plateau is evident, and then while MNs being further inserted in the skin, the resisting force increases again due to the friction between the needles and the skin tissues, as well as the compression of the skin–MN system .…”

Rapidly Dissolving Microneedles for the Delivery of Steroid-Loaded Nanoparticles Intended for the Treatment of Inflammatory Skin Diseases

“…These peaks were attributed to the stretching vibrations of C=O and C=C (in a ring) double bond framework conjugated to C=O bonds in DEX. The characteristic peak of PLGA was identified at 1747.51 cm −1 due to the ester group [ 22 ]. The spectrum of the physical mixture exhibited relatively similar peaks of DEX and PLGA, including the band at 893 cm −1 that corresponds to the axial deformation of the C-F group in DEX.…”

“…The dissolving capability of the polymeric tips affects the release rate of NPs from MNs. Herein, ex vivo chicken skin, frequently used for the characterization of microneedle arrays [ 22 , 44 , 45 ], and agarose gel, mimicking the mechanical properties of human skin [ 39 , 42 , 46 ], were employed to determine the time for morphological changes to occur in the structure of MNs after insertion. The NP-MNs were gradually dissolved within 2 min after insertion into ex vivo chicken skin, with a bending already visible after 15 s. The needle height of NP-MNs decreased to ca.…”

“…SA-MNs and NP-MNs were manually pushed into 8 stacked parafilm layers as a skin stimulant for 30 s and observed under a stereomicroscope (Olympus-SZ61, Tokyo, Japan) to study the insertion efficiency and MN insertion depth [ 21 ]. The insertion was expressed in the number of pores created in each parafilm layer, and the rate of change of the height (µm) of 10 randomly selected MNs was calculated and plotted as the percentage of reduction in MN height [ 22 ].…”