DESCRIPTION
AVITA® Cream, a topical retinoid, contains tretinoin 0.025% by weight in a hydrophilic cream vehicle of stearic acid, polyolprepolymer-2, isopropyl myristate, polyoxyl 40 stearate, propylene glycol, stearyl alcohol, xanthan gum, sorbic acid, butylated hydroxytoluene, and purified water. Chemically, tretinoin is all-transretinoic acid (C20H2802; molecular weight 300.44 vitamin A acid) and has the following structural formula:
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CLINICAL PHARMACOLOGY
Although the exact mode of action of tretinoin is unknown, current evidence suggests that topical tretinoin decreases cohesiveness of follicular epithelial cells with decreased microcomedo formation. Additionally, tretinoin stimulates mitotic activity and increased turnover of follicular epithelial cells causing extrusion of the comedones.
Pharmacokinetics
In vitro and in vivo pharmacokinetic studies with AVITA® Cream indicate that less than 0.3% of the topically applied dose is bioavailable. Circulating plasma levels of both tretinoin and isotretinoin are only slightly elevated above those found in healthy normal controls.
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CLINICAL STUDIES
In one vehicle-controlled clinical trial, AVITA® (tretinoin cream) Cream 0.025%, applied once daily was more effective than vehicle in the treatment of facial acne vulgaris of mild to moderate severity. Percent reductions in lesion count after treatment for 12 weeks in this study are shown in the following table:
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| Avita® Cream,
0.025% |
Vehicle
Cream |
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| N = 75 |
N = 58 |
| Noninflammatory Lesions |
45% |
27% |
| Inflammatory Lesions |
46% |
32% |
| Total Lesions |
46% |
28% |
| N = Number of Subjects |
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