The absence of androgens, Müllerian-inhibiting substance (MIS), and testes causes the continuous differentiation of the Müllerian ducts with reversion of the wolffian ducts in the female embryo. The Müllerian duct will then elongate to reach the urogenital sinus within 9 weeks of gestation; this forms the uterovaginal canal. By 15–26 weeks of gestation, cephalic growth of the sinovaginal bulb is completed. The vaginal plate is also formed from the fusion of vaginal cord with the sinovaginal bulb. The formation of the uterovaginal canal is thought to occur from the caudal to the cephalic portion, all while the urogenital sinus is used to create the epithelial lining. Development of the vagina is completed by the fifth month of gestation. While the mesenchyme that surrounds the structures transitions into musculature of the genital tract, the fallopian tubes are formed via the cephalic remnants of the Müllerian duct. This developmental process attributes to the process of how proper vaginal development takes place. Failure of the septum to regress between the fused Müllerian ducts results in a septate uterus. The incomplete fusion of the Müllerian ducts attributes to the formation of arcuate, bicornuate, or didelphid uteri.Females who have both Rokitansky-Mayer-Küster-Hauser syndrome and uterovaginal atresia are theorized to have a failing caudal development within the Müllerian ducts. Variations of transverse vaginal septum might be described by the malfunctions at the level of the vaginal plate.
According to one report in 1988, azelaic acid in combination with zinc sulfate in vitro was found to be a potent (90% inhibition) 5α-reductase inhibitor, similar to the hair loss drugs finasteride and dutasteride. In vitro research during mid-1980s evaluating azelaic acids depigmenting (whitening) capability concluded it is effective (cytotoxic to melanocytes) at only high concentrations.A 1996 review claimed 20% AzA is as potent as 4% hydroquinone after a period of application of three months without the latters adverse effects and even more effective if applied along with tretinoin for the same period of time. Brand names
Brand names for azelaic acid include Dermaz 99, Crema Pella Perfetta (micronized azelaic acid, kojic dipalmitate, and liquorice extract), Azepur99, Azetec99, Azaclear (azelaic acid and niacinamide), AzClear Action, Azelex, White Action cream, Finacea, Finevin, Melazepam, Skinoren, Ezanic, Azelac, Azaderm, (Acnegen, Eziderm, Acnicam, Azelexin in Pakistan)

References
External links
DermNet treatments/azelaic-acid"Azelaic Acid Topical". MedlinePlus.