The Microsponge Delivery System Reduces Facial Oiliness and Shine During Acne Therapy

November 2013 | Volume 12 | Issue 11 | Original Article | 1268 | Copyright © November 2013

Leon H. Kircik MD

Indiana University School of Medicine, Indianapolis, IN
Mount Sinai Medical Center, New York, NY
Physicians Skin Care, PLLC, Louisville, KY

Acne therapies that are able to show efficacious treatment of acne lesions as well as to address the issues of oiliness and shine control may be particularly appropriate for the treatment of patients with acne vulgaris that is accompanied by oily skin and facial shine. The microsphere delivery system (MDS), a novel delivery technology for topical therapy, can be customized to optimize product attributes, including oil absorption. Clinical trials have clearly established the efficacy and tolerability of such MDS formulations in the treatment of acne. In addition, studies have shown that the use of products formulated with an MDS provides a more significant reduction in facial shine than non-MDS acne therapy, as well as a reduction in facial sebum accumulation relative to control. Future clinical research should aim to further delineate the effect of individual topical acne treatment formulations on oiliness and shine.

J Drugs Dermatol. 2013;12(11):1268-1270.


Current topical treatments for acne include topical retinoids such as tretinoin, antimicrobials such as clindamycin, erythromycin, and benzoyl peroxide (BP), and combination products. Recent advances in vehicle technologies, not only allow for delivery of active ingredients with improved efficacy and tolerability, but also offer added benefits such as reduction in oiliness and facial shine.1-3 In particular, topical drug therapy formulations using controlled-release microsphere delivery systems (MDS) have been shown to absorb facial oil.4,5 Considering that acne is a complex condition characterized by excessive sebum production from the sebaceous follicle6,7 and associated oiliness and facial shine,6,8-11 addressing oil-related concerns among acne sufferers may prove to increase patient satisfaction with treatment.8,12

Use of the Microsphere Delivery System in Dermatology

The MDS uses patented polymeric microspheres that are designed to release active ingredient slowly over time.4,13 The microspheres are formed by polymeric cross-linking, with multiple interconnecting spaces. These porous microspheres are loaded with the drug by diffusion, acting similarly to a sponge, and are able to entrap a wide range of active ingredients such as emollients, essential oils, and sunscreens.13 While resembling a sponge in structure and function, the microspheres are rigid and virtually noncompressible due to the high amount of cross-linking in the polymeric structure.5
The macroporous beads, typically measuring 10-25 μm in diameter, release active ingredient over time in response to stimuli like physical manipulation when rubbed into the skin (pressure) or a change in pH or temperature.4 The rate of release of active ingredient also may be affected by factors such as the extent of polymer cross-linking of the MDS (with more extensive cross-linking yielding a slower release rate), pore volume, and microsphere particle size.4,13 Considering that the microspheres themselves are too large to permeate the stratum corneum and the active ingredient is not available until it leaves the microsphere, there is lower accumulation of the drug at the epidermis.4 This gradual release rate extends the duration of beneficial effects of the active ingredient while minimizing cutaneous irritation; the particles can reside on the surface of the skin, thereby delivering active ingredient for a prolonged period of time.4 Parameters of the MDS, such as particle size, pore volume, diameter, and release characteristics, can be customized to meet the needs of a specific therapeutic agent.5,13
The MDS technology is found across many dermatologic applications, including for treatment of actinic keratoses or solar keratoses, skin depigmentation, and acne. Carac® 5-fluorouracil (5-FU) cream (Dermik; Bridgewater, NJ) utilizes 0.5% 5-FU in a 0.35% patented porous MDS for treating actinic keratosis or solar keratoses of the face or anterior scalp.14 This formulation was shown to reduce the irritation associated with administration of 5-FU.15 A combination of hydroquinone and retinol (EpiQuin Micro®; SkinMedica, Inc., Carlsbad, CA) is entrapped in an MDS for delivering these active agents together in a controlled-release manner for skin brightening.16 Oil-free mattifying agents also have employed MDS technology to absorb excess surface oils on the skin (eg, over-the-counter brands such as Dermalogica® Oil Control Lotion, which utilizes a vinyl dimethicone/methicon silsesquioxane cross-polymer MDS17).
For treating acne vulgaris, tretinoin microsphere gel 0.1% and 0.04% (Retin A Micro®; Valeant Dermatology, Bridgewater, NJ) is encapsulated in a patented methyl methacrylate/glycol dimethacrylate cross-polymer MDS in an aqueous gel.18 As well as reducing the potential for skin irritation with tretinoin, the