Microneedles Drug Delivery Systems for Treatment of Cancer: A Recent Update

Abstract

Microneedles (MNs) are tiny needle like structures used in drug delivery through layers of the skin. They are non-invasive and are associated with significantly less or no pain at the site of administration to the skin. MNs are excellent in delivering both small and large molecules to the subjects in need thereof. There exist several strategies for drug delivery using MNs, wherein each strategy has its pros and cons. Research in this domain lead to product development and commercialization for clinical use. Additionally, several MN-based products are undergoing clinical trials to evaluate its safety, efficacy, and tolerability. The present review begins by providing bird's-eye view about the general characteristics of MNs followed by providing recent updates in the treatment of cancer using MNs. Particularly, we provide an overview of various aspects namely: anti-cancerous MNs that work based on sensor technology, MNs for treatment of breast cancer, skin carcinoma, prostate cancer, and MNs fabricated by additive manufacturing or 3 dimensional printing for treatment of cancer. Further, the review also provides limitations, safety concerns, and latest updates about the clinical trials on MNs for the treatment of cancer. Furthermore, we also provide a regulatory overview from the "United States Food and Drug Administration" about MNs.

Keywords: breast cancer; non-invasive; regulatory; skin carcinoma; transdermal drug delivery.

Figure 1

History of Microneedles (MNs) (a) Plan view of the microneedle device from reference [36] (b–d) Plan view of microneedle device, substantially to scale, blown-up to shown the MNs from reference [37] (e) MNs patented by Alza Corporation, from reference [38].

Figure 2

Strategies for drug delivery using MNs (a) “Poke and Patch” Strategy (b) “Coat and Poke” Strategy (c) “Poke and Release” Strategy [30,56,57,58] (d) “Poke and Flow” Strategy.

Figure 3

Schematic illustration of general characteristics of MNs.

Figure 4

Design and geometry of MNs (a) Illustration of geometrical parameters in a microneedle array (b) Geometry of MNs length (L), thickness (T) and width (W) (c) Different shapes of MNs (i) Rectangular microneedle with sharp edge (ii) cylindrical (iii) conical (iv) tapered (v) arrow headed.

Figure 5

Microneedles (MNs) sensing modalities (a) sensor positioned on the MNs base or support (b) electrode inserted into the hollow microneedles—acts electrochemically (c) surface of the MNs is functionalized to act as a sensor (d) MNs are metallized to act as bio-electrodes.

Figure 6

Microneedles for treatment of cancer (a) Illustration showing MNs with sensor unit when applied to skin (b) Microneedle array device with probe (c) Light emitting fiber optic microneedle converting 5-Aminolevulinic acid (5-ALA) to Protoporphyrin IX (PPIX).

Figure 7

Honokiol: Biphenyl natural anti-cancer compound from Magnolia glandiflora.

Figure 8

Cross-section of the microneedle after drug cargo loading by micro-milling.

Figure 9

Advantages of MNs.