estradiol norethindrone acetate transdermal system - Generic Medications

CombiPatch ® (estradiol/norethindrone acetate transdermal system) is an adhesive-based matrix transdermal patch designed to release both estradiol, an estrogen, and norethindrone acetate (NETA), a progestational agent, continuously upon application to intact skin. Two systems are available, providing the following in vivo delivery rates of estradiol and NETA. 1 NETA=norethindrone acetate. 2 Based on in vivo/in vitro flux data, delivery of both components per day via skin of average permeability (interindividual variation in skin permeability is approximately 20 percent). System Size Estradiol (mg) NETA 1 (mg) Nominal Delivery Rate 2 (mg per day) Estradiol / NETA 9 cm 2 round 0.62 2.7 0.05/0.14 16 cm 2 round 0.51 4.8 0.05/0.25 Estradiol USP (estradiol) is a white to creamy white, odorless, crystalline powder, chemically described as estra-1,3,5(10)-triene-3,17 β -diol. The molecular weight of estradiol is 272.39 and the molecular formula is C 18 H 24 O 2 . NETA USP is a white to creamy white, odorless, crystalline powder, chemically described as 17-hydroxy-19-nor-17α-pregn-4-en-20-yn-3-one acetate. The molecular weight of NETA is 340.47 and the molecular formula is C 22 H 28 O 3 . The structural formulas for estradiol and NETA are: CombiPatch is comprised of 3 layers. Proceeding from the visible surface toward the surface attached to the skin, these layers are (1) a translucent polyolefin film backing, (2) an adhesive layer containing estradiol, NETA, acrylic adhesive, silicone adhesive, oleic acid NF, povidone USP and dipropylene glycol, and (3) a polyester release protective liner, which is attached to the adhesive surface and must be removed before the system can be used. The active components of the system are estradiol USP and NETA USP. The remaining components of the system are pharmacologically inactive. Chemical Structure Layer