UI, urinary incontinence. Data from Dmochowski RR et al.23 A potential limitation of transdermal drug delivery devices is the risk for application site reactions (ASE). Skin adverse events can result from the drug, adhesive, permeation enhancer, or can be due to the occlusive nature of the device. The most common ASEs are allergic contact dermatitis, irritant dermatitis, alterations in skin pigmentation, redness, pruritis, or local edema.24 Erythema (8.3%) and itchiness (14.0%) Inhibitors,research,lifescience,medical are the most commonly reported skin adverse events associated with OXY-TDS and are usually mild or moderate in severity.22,23 Erythema usually resolves spontaneously within days and requires no treatment. Itchiness is usually

Inhibitors,research,lifescience,medical due to skin dryness and can be alleviated by liberal usage of skin moisturizers and application site rotation. The “ring around the patch” residue can be removed with warm

soap and water, or, in some cases, baby oil. Nail polish remover (acetone) can irritate the skin and should be avoided. Simple patch and skin care instructions given to patients have been shown to significantly decrease the incidence and severity of local skin reactions in phase IV studies.25 Oxybutynin Chloride Topical Gel Oxybutynin chloride topical gel (OTG) was recently Inhibitors,research,lifescience,medical approved by the FDA for the treatment of overactive bladder. The once-daily gel formulation (Gelnique™; Watson Pharma) uses a small application volume (1.14 mL/dose; 1 g) that is applied to the abdomen, thigh, Dynasore cell line shoulder, or upper arm. OTG is quick drying, colorless, and leaves no residue. Its hydroalcoholic system utilizes ethanol as a skin permeation enhancer and a glycerin emollient to soften Inhibitors,research,lifescience,medical the skin and to minimize dryness.

Steady-state plasma concentrations of both oxybutynin and N-DEO are Inhibitors,research,lifescience,medical achieved within 1 week of OTG application and with similar plasma concentrations to OXY-TDS.26 A parallel group study demonstrated equal bioavailability and steady-state pharmacokinetics of oxybutynin and N-DEO following gel applications to the abdomen, upper arm/shoulder, and thigh (Figure 2). In addition, its pharmacokinetic profile is not adversely affected by sunscreen application or showering.27 Figure 2 Oxybutynin transdermal gel bioequivalence for (A) oxybutynin and (B) N-desethyloxybutynin (DEO), when applied to abdomen, thigh, and upper arm. Transference Megestrol Acetate is a potential issue with transdermal gels and creams. Minor person-to-person transference of OTG occurs with skin contact, but it is minimal, likely not clinically important, and largely eliminated by covering the application site with clothing.27 The OTG formulation further improves the favorable metabolite-to-parent (N-DEO/oxybutynin) plasma concentration ratio that is seen with OXY-TDS.28,29 The mean DEO:oxybutynin AUC0−96 ratios achieved with OTG and OXY-TDS were 0.77 and 1.07, respectively.