Mixtard 50 HM Penfill Composition
Mixtard 50 HM Penfill contains 50% soluble human insulin (regular insulin) and 50% isophane human insulin (NPH insulin) in a premixed formulation.
Active Ingredients
- 50% Human Regular Insulin: This is the rapid-acting component that provides immediate glucose control after injection 1, 2
- 50% Human NPH Insulin: This is the intermediate-acting component that provides sustained insulin coverage throughout the day 1, 2
The "HM" designation indicates this is human insulin (as opposed to animal-derived insulin), and the formulation is designed for use in pen injection devices (Penfill cartridges) 1.
Pharmacokinetic Profile
- The 50/50 ratio provides higher initial insulin concentrations and a greater early glucose-lowering response compared to 70/30 mixtures, making it particularly useful when greater initial postprandial glucose control is required 2
- The regular insulin component has onset of action within 30 minutes and should ideally be administered 30 minutes before meals for optimal effect 3
- The NPH component provides intermediate-acting coverage with onset at approximately 1 hour, peak at 6-8 hours, and duration of approximately 12 hours 3
Clinical Considerations
- This 50/50 formulation is typically administered twice daily (before breakfast and before the evening meal) 2, 4
- The higher proportion of rapid-acting insulin (50% vs 30% in standard 70/30 mixtures) makes it more appropriate for patients with high carbohydrate intake or those requiring better postprandial glucose control 4
- Studies demonstrate that 50/50 mixtures produce equivalent total bioavailability to 70/30 mixtures but with enhanced early glucose control 2
Important Safety Points
- Requires consistent meal timing and content due to the NPH peak action profile to minimize hypoglycemia risk 3
- May carry higher risk of nocturnal hypoglycemia compared to long-acting insulin analogs due to the NPH component 3
- Should be inspected before each use to ensure the suspension appears uniformly cloudy after gentle mixing 1
Human insulin formulations like Mixtard 50 HM represent a cost-effective alternative to insulin analogs, with availability at approximately $25-35 per vial in some settings 3.