Hyaluronic acid is a popular ingredient used in skincare regimens today that can be found in products ranging from serums to sheet masks. It is a non-sulfated glycosaminoglycan molecule that occurs naturally in the skin in the extracellular matrix molecules. Hyaluronic acid is an important component in skin moisture because of its ability to retain water molecules therefore acting as a humectant. Skin aging is affected by both intrinsic and extrinsic processes. Intrinsic processes are unpreventable and include hormonal changes as you age such as decreased estrogens and androgens leading to less collagen. Extrinsic processes include ultraviolet radiation exposure which causes skin damage. As you age, hyaluronic acid polymers shrink and the epidermis loses hyaluronic acid which leads to dehydration, atrophy, and loss of elasticity of the skin. There was a double blind, randomized study done to evaluate the effectiveness of a hyaluronic acid based product to decrease aging signs and improve face volume in wrinkles. The tested product was called Fillerina and the study was done with 40 female subjects with 20 divided into the 2 groups. The subjects’ loss of volume of their face contours, cheekbones and lips as well as wrinkles depth and volume were measured before the start of the study and after day 7, 14, and 30. Compared to the placebo group, the treatment group had an improvement in skin sagging and decreased wrinkle depth and volume. The placebo group had a slight worsening of their skin sagging but this can be due to normal differences in how much a person's skin sags. Overall, it was shown that the use of hyaluronic acid can improve skin moisturization and the appearance of aged skin.
References
Nobile V, Buonocore D, Michelotti A, Marzatico F. Anti-aging and filling efficacy of six types hyaluronic acid based dermo-cosmetic treatment: double blind, randomized clinical trial of efficacy and safety. J Cosmet Dermatol. 2014;13(4):277-287. doi:10.1111/jocd.12120
Papakonstantinou E, Roth M, Karakiulakis G. Hyaluronic acid: A key molecule in skin aging. Dermatoendocrinol. 2012;4(3):253-258. doi:10.4161/derm.21923
Transdermal drug delivery systems (TDDS) offer a noninvasive method for systemic medication administration through the skin, providing several advantages over traditional oral or parenteral routes. These systems deliver drugs across the stratum corneum and into systemic circulation at controlled rates, allowing for consistent plasma levels, avoidance of first-pass metabolism, and improved patient adherence through convenient dosing.
Successful transdermal delivery requires that the drug possesses specific physicochemical properties, including low molecular weight (<500 Da), sufficient lipophilicity, and potency at low doses. Commonly used agents in current transdermal formulations include nicotine, fentanyl, buprenorphine, clonidine, nitroglycerin, and hormonal therapies such as estradiol and testosterone. Advances in transdermal technology have also expanded into newer areas such as microneedle patches, iontophoresis, and chemical enhancers designed to temporarily disrupt or bypass the skin barrier.
Despite their benefits, transdermal systems present unique challenges. Skin irritation at the application site is among the most frequent adverse effects, and allergic contact dermatitis to the drug itself, the adhesive, or excipients can occur. Inconsistent drug absorption can also arise due to variability in skin hydration, temperature, thickness, or integrity. External factors such as heat exposure (from heating pads or fever) can significantly increase drug absorption and result in unintentional overdose, particularly with opioids like fentanyl. Pharmacists play a critical role in counseling patients to avoid external heat sources, rotate application sites, monitor for skin reactions, and properly dispose of used patches to prevent accidental exposure.
From a pharmacy practice standpoint, understanding the pharmacokinetics of transdermal systems, application techniques, site rotation schedules, and proper storage and disposal is essential. Pharmacists are also key in ensuring correct patient selection for TDDS, as certain populations (cachectic patients or those with skin disorders like psoriasis or eczema) may have altered drug absorption profiles. Additionally, pharmacists must educate patients on not cutting patches unless specified by the manufacturer, as doing so can compromise delivery systems and lead to dose dumping.
Transdermal systems continue to evolve with innovations aiming to deliver larger molecules, vaccines, and biologic agents through the skin. As the technology advances, pharmacists will remain central to patient education, safety monitoring, and ensuring appropriate therapeutic use of these specialized drug delivery platforms.
Prausnitz MR, Langer R. Transdermal drug delivery. Nat Biotechnol. 2008;26(11):1261–1268. doi:10.1038/nbt.1504
Guy RH. Transdermal drug delivery. In: Swarbrick J, ed. Encyclopedia of Pharmaceutical Technology. 3rd ed. Informa Healthcare; 2007:3707–3717.
Gupta J, Felner EI, Prausnitz MR. Minimally invasive insulin delivery in subjects with type 1 diabetes using hollow microneedles. Diabetes Technol Ther. 2009;11(6):329–337. doi:10.1089/dia.2008.0089
Benson HA. Transdermal drug delivery: penetration enhancement techniques. Curr Drug Deliv. 2005;2(1):23–33. doi:10.2174/1567201052772915