Coated polymeric needles for rapid and deep intradermal delivery

Eneko Larrañeta,Qonita Kurnia Anjani,Álvaro Cárcamo-Martínez,Ryan F. Donnelly,Ana Sara Cordeiro,Andi Dian Permana

doi:10.1016/j.ijpx.2020.100048

Eneko Larrañeta, Qonita Kurnia Anjani + Show 4 more

Open Access

https://doi.org/10.1016/j.ijpx.2020.100048

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Abstract

Two groups of single polymeric needles (crosslinked Gantrez®S-97 and poly(ethylene glycol)) of different lengths (2 mm and 4.5 mm) with defined base widths were fabricated and tested in terms of their mechanical strength and insertion abilities using two skin models (Parafilm® and porcine skin). For the shorter needles, application of an axial force (32 N) resulted in a height reduction of approximately 80%. Nonetheless, around 80% of total needle length was successfully inserted in both skin models. Optical coherence tomography showed that base width highly impacted insertion capabilities of the longer needles as only the thicker one (0.922 mm width at base) inserted into porcine skin. Additionally, needles were coated with rhodamine B and inserted into porcine skin. In comparison to a control, penetration depth of the model drug increased 2-fold for short and 4.5-fold for long needles, respectively. Moreover, quantification across skin sections showed that shorter needles delivered 10 μg of the compound in a depth of 1.5–2.0 mm while long needles were capable of delivering 5 μg into even deeper skin layers (2.0–3.0 mm), confirming the potential of coated polymeric needles for rapid and deep intradermal delivery.

Highlights

The oral route is currently the most common path for drug administration because of its simplicity and non-invasive character
In a second attempt (Fig. 3B), a hole was added to the 3D design, which made possible to fix the needle to the printed template using glue
Coated needles were inserted into porcine skin, left for 15 min for Several approaches were investigated in the manufacture of master moulds for the fabrication of single hydrogel-forming needles

Summary

Introduction

The oral route is currently the most common path for drug administration because of its simplicity and non-invasive character. The stratum corneum is the outermost sublayer of the epidermis and is composed, inter alia, by corneocytes (protein-enriched cells) embedded in an extracellular lipid mixture of ceramides, cholesterol, and free fatty acids Both corneocytes and this lipid mixture serve as barrier against the percutaneous penetration of chemicals and microbes (Benson and Watkinson, 2011; Menon et al, 2012; Proksch et al, 2008), limiting diffusion of drugs into the skin. Polymers will be in contact with the interstitial fluid and dissolution or swelling takes place, releasing the drug into the epidermis or upper dermis (Donnelly et al, 2012; Ramöller et al, 2019) Since these processes may take time, inclusion of drugs on the surface of MNs using coating formulations has been investigated in order to speed up the release. Gas-jet drying, spray drying, ink-jet printing are some of the techniques reported (Haj-Ahmad et al, 2015; Ingrole and Gill, 2019; Tarbox et al, 2018), which have been tested for the development of coated MNs with influenza vaccine, lidocaine, insulin, miconazole, 5-fluorouracil, among others (Baek et al, 2017; Boehm et al, 2014; Choi et al, 2012; Ross et al, 2015; Uddin et al, 2015)

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