"(3α,5α,17α)-13-Ethyl-18,19-dinorpregn-20-yne-3,17-diol (ACI) 18,19-Dinor-5α,17α-pregn-20-yne-3α,17-diol, 13-ethyl","(3α,5α,17α)-13-Ethyl-18,19-dinorpregn-20-yne-3,17-diol (ACI) 18,19-Dinor-5α,17α-pregn-20-yne-3α,17-diol, 13-ethyl",Levonorgestrel Impurity