This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pancreas, Subject name: Pharmacology
Which of the following insulin should not be mixed with other insulins? 
Select and explain. 
A. Glargine, B. Aspa, C. Lispro, D. Regular
A: Glargine
Answer: A: Glargine 
Explanation: Insulin preparations: Sho acting insulin - Aspa Glulisine Lispro Regular Intermediate acting -> Lente insulin Long acting insulin Detemir Degludec NPH Ultra long acting insulin: Glargine Inhaled insulin - Afrezza All insulin preparation are available at neutral pH. Insulin glargine has acidic pH<4, so insulin glargine should not be mixed with any other insulin.