This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Which insulin is never mixed with other insulins? 
Select and explain. 
A. Utile, B. Aspa, C. Lispro, D. Glargine
D: Glargine
Answer: D: Glargine 
Explanation: Ans. is 'd' i.e., Glargine o All insulin preparations are supplied at neutral pH (7.2-7.4) except glargine (supplied at pH 4.0); therefore, glargine cannot be mixed with any insulin.