What does "V" mean for compound amino acid injection (18aa-v)?

The manufacturer of "18AA-V" is compound amino acid injection (18aa-v)100ml: 3.224g (total amino acid) +5g (xylitol) Fuzhou Haiwangfu Pharmaceutical Co., Ltd. (Mu An) Yichang Branch of Hubei Feng Ba Pharmaceutical Co., Ltd. (Mo Lifeng). 500ml: 16. 12g (total amino acids) ++25g (xylitol) Fuzhou Wanghai Fuyao Pharmaceutical Co., Ltd. (Liming) Hubei Yibantian Pharmaceutical Co., Ltd. Jiangsu Yao Peng Pharmaceutical Co., Ltd. Compound amino acid injection (18AA-V)250ml:8.06g (total amino acids). Hubei Feng Ba Pharmaceutical Co., Ltd. Yichang Branch (Mo Lifeng) Hubei Yibantian Pharmaceutical Co., Ltd. Jiangsu Kangbao Pharmaceutical Co., Ltd. These are manufacturers of different specifications, all of which are online.