Hospira is made under controlled sanitary conditions with exact ratios and procedures. Off-brand versions are unpredictable, and most tested vials have failed. There are many threads here on the different approaches to DIY mixing. For most people outside the USA, it's either that or plain sterile water.
Does the company name actually make a difference? It is made up of nothing but sterile water along with benzyl alcohol. Purchasing water and alcohol that meet USP standards and combining them exactly in the right proportions, wouldn't that end up being identical to the original product?