The difference is the same as that between glucose injection and glucose sodium chloride injection used clinically. The latter contains more sodium chloride. Clinically, the former is commonly known as "sugar water" and the latter as "sugar salt water". The same is true for Xylitol Injection and Xylitol Sodium Chloride Injection.
All four are diluents or energy supplements for clinical infusion.
Because xylitol does not increase blood sugar, it is used as a sugar substitute for diabetic patients during infusion.