Novel iron oxide nanocarriers loading finasteride or dutasteride: Enhanced skin penetration for topical treatment of alopecia.

In the present study, iron oxide nanoparticles, in the form of maghemite core coated with lauric acid (ION), were synthesized and loaded with finasteride (FIN) or dutasteride (DUT) as a novel drug delivery system for the topical treatment of alopecia. Additionally, developed formulations (FIN-ION and DUT-ION) were completely elaborated with components involved in the follicle metabolism, i.e., lauric acid, which acts as a 5α-reductase inhibitor, and iron which deficiency has been related to hair loss aggravation. Stability assessment conducted over the course of 90 days showed they are highly stable, with pH 7.4, constant EE% (>99%), and practically unchanged particle size and zeta potential. Besides drug distribution, the actual number of iron oxide nanoparticles, through a newly developed method using ferromagnetic resonance, was determined in each skin layer following permeation experiments. Despite the same donor concentration of colloids, nanoparticle distribution in the skin varied according to the loaded molecule. While DUT did not interfere with the nanoparticle natural tendency to accumulate within the hair follicle shafts, FIN presence hampered nanosystem interaction with the skin. Still, both formulations provided a higher skin drug penetration, compared to each respective control solution. Additionally, iron nanocarriers present a desirable visual characteristic, as the dark color aspect might instantly help disguise scarce hair follicle areas. These findings suggest the nanoformulations are highly promising for alopecia therapies.

Dutasteride nanocapsules for hair follicle targeting: Effect of chitosan-coating and physical stimulus.

In general, nanometer-sized drug delivery systems have a natural tendency for accommodation in the follicular cavities, which makes them advantageous in the treatment of conditions affecting these structures. Still, follicular targeting enhancement can improve therapy outcomes. Here, we compare two strategies to further promote dutasteride follicular-targeted delivery: the chemical modulation of nanosystem surface properties by coating with the natural polymer chitosan, and the application of a massage. For this, poly-(ɛ-caprolactone)-lipid-core nanocapsules (NC) containing dutasteride were developed and had their permeation profile compared to chitosan-coated nanocapsules (NC-CS). Nanocapsules showed high drug encapsulation efficiency (>94%), and stability for up to 90 days of storage. As expected, chitosan coating increased the size and zeta potential, from 199.0 ± 0.5 nm (PdI of 0.12) and - 13.6 ± 0.6 mV to 224.9 ± 3.4 nm (PdI 0.23) and + 40.2 ± 0.8 mV, respectively. Both coated and non-coated nanoparticles targeted the hair follicles compared to a drug solution. Enhanced hair follicles targeting was observed after the massage procedure, with 5 and 2-fold increases relative to NC and NC-CS, respectively. In conclusion, this work demonstrates dutasteride nanocapsules can target the follicular casts, and a simple physical stimulation can enhance 5-times the drug amount accumulated.

Nanotechnology advances for hair loss.

Alopecia is the partial or total reduction of hair in a specific area of the skin that affects millions of men and women worldwide. Most common approved treatments present inconvenient therapeutic regimes and serious adverse effects. In this scenario, nanoencapsulation has emerged as a relatively simple technology for improving the therapeutic outcome of this pathology, promoting a targeted drug delivery with enhanced local bioavailability, which could reduce the adverse effects. Herein, we present some recent studies involving the nanosystems developed for the pharmacological treatment of alopecia, highlighting how each system represents an improvement in relation to conventional drug products and the future perspectives of these new technologies in reaching the market.