How do I reconstitute a 10 IU vial of human growth hormone (HGH) using sterile technique?

Reconstituting 10 IU Human Growth Hormone

To reconstitute a 10 IU vial of HGH, add 1 mL of bacteriostatic water slowly down the side of the vial, gently swirl (never shake) until fully dissolved, and store refrigerated at 2-8°C for up to 28 days when using bacteriostatic water as the diluent. 1

Diluent Selection and Volume

• Use bacteriostatic water containing approximately 0.9% benzyl alcohol as preservative, which permits multi-dose use for up to 28 days when refrigerated 1
• For a 10 IU vial, add 1 mL of bacteriostatic water to achieve a standard concentration of 10 IU/mL, providing convenient dosing 1
• Never use sterile water for injection without preservative for multi-dose vials, as this significantly increases contamination risk 1
• Phenol (3 mg/mL) and benzyl alcohol (3-9 mg/mL) are both safe and effective preservatives used in GH formulations, with phenol showing similar or better tolerability compared to m-cresol 2

Aseptic Reconstitution Technique

• Sanitize the rubber stopper with 70% isopropanol before inserting the needle to prevent microbial contamination 1
• Maintain strict sterile technique throughout, avoiding contact of needle, syringe, or stopper with non-sterile surfaces 1
• Inject the diluent slowly down the side of the vial wall rather than directly onto the powder to minimize foaming and protein denaturation 1, 3
• Gently swirl the vial in a circular motion until the powder is completely dissolved—vigorous shaking can cause protein aggregation and gel formation 1, 3
• Perform visual inspection after reconstitution, checking for complete clarity, absence of particulate matter, and no discoloration 1, 3

Critical Reconstitution Pitfalls

The reconstitution method significantly impacts product quality:

• Rapid injection directly onto the powder surface causes the most gel formation and particulate matter compared to slow injection down the vial wall 3
• Fibrous particulate matter and degradation products can form in all preparations if reconstituted improperly 3
• Do not use powder that appears discolored or has been exposed to moisture prior to reconstitution 1

Storage and Labeling

• Label the reconstituted vial immediately with patient identifier, concentration (10 IU/mL), reconstitution date, and beyond-use date 1
• Store at 2-8°C (36-46°F) in the refrigerator after reconstitution 1
• Discard after 28 days when using bacteriostatic water, or sooner if discoloration or particulate matter develops 1
• Discard immediately if the solution becomes cloudy, discolored, or contains visible particles 1

Stability Considerations

• Do not retain reconstituted solutions beyond validated timeframes—many GH formulations become unstable after reconstitution despite refrigeration 1
• Some liquid GH formulations are more susceptible to denaturation after storage in solution compared to freshly reconstituted powder 3
• Assume limited stability in the absence of specific validated data for your particular product 1

Buffer and Preservative Impact

• Histidine-buffered solutions cause less injection pain than citrate-buffered solutions 2
• Higher protein concentrations and larger injection volumes are associated with increased pain perception 2
• The preservative concentration matters: m-cresol (9 mg/mL) causes more painful injections than phenol (3 mg/mL) or benzyl alcohol (3-9 mg/mL) 2