Beyond Use Date for Liquid Mixes
The beyond use date for liquid mixes depends on the specific type of preparation: for home parenteral nutrition (HPN) admixtures, the hanging time should not exceed 24 hours, while for allergen immunotherapy extract dilutions, the beyond use date should not exceed the expiration date of the earliest expiring constituent in the mixture. 1
Home Parenteral Nutrition (HPN) Liquid Admixtures
For ready-to-use HPN admixtures, the maximum hanging time is 24 hours, with the giving set changed upon each new dosing. 1
Critical Storage and Handling Requirements
Customized all-in-one (AIO) admixtures require cold chain maintenance during transport and at the patient's home to preserve stability and prevent degradation 1
Labels must indicate the date of manufacturing and expiring along with patient name, composition, storage instructions, and infusion rate to prevent medication errors 1
Important Pitfall to Avoid
- Drug admixing into AIO admixtures should be avoided unless specific pharmaceutical compatibility data are documented, as these mixtures have high potential for drug interactions leading to incompatibilities or stability issues 1
Allergen Immunotherapy Extract Dilutions
The expiration date of any allergen extract dilution must not exceed the expiration date of the earliest expiring constituent added to the mixture. 1, 2
Storage and Stability Guidelines
Allergen extracts must be stored at 4°C (refrigerated) to minimize potency loss, as higher temperatures accelerate deterioration 1, 2
More dilute concentrations (greater than 1:10 vol/vol) lose potency more rapidly than concentrated extracts and are more sensitive to temperature effects 2
Extracts beyond the manufacturer's expiration date must be discarded, as emphasized by the American Academy of Allergy, Asthma, and Immunology (AAAAI), American College of Allergy, Asthma, and Immunology (ACAAI), and Joint Council of Allergy, Asthma, and Immunology (JCAAI) 1, 2
Bacteriostasis Requirements
- Allergen extract dilutions must be bacteriostatic, containing either phenol concentrations of at least 0.25% or glycerin concentrations of at least 20% if phenol is less than 0.25% 1
Evidence Limitations and Clinical Implications
The AAAAI Immunotherapy and Allergy Diagnostic Committee found that standardized extracts (short ragweed at 1:10 vol/vol, dust mite and cat at 1:10 and 1:100 vol/vol) remained stable for 12 months under various storage conditions, though expiration dates for allergen extract dilutions remain somewhat empiric and not strongly evidence-based 1
Using expired extracts risks unpredictable patient responses due to unknown potency and potential treatment failure from subtherapeutic dosing 2
General Compounded Oral Liquid Preparations
For other compounded oral liquid preparations, beyond use dates vary significantly based on the specific active pharmaceutical ingredient, excipient interactions, and storage conditions 3, 4, 5, 6
The United States Pharmacopoeia (USP) suggests a 6-month beyond use date for dry oral forms, though stability studies for specific formulations may support different timeframes 3
Drug-excipient interactions can significantly impact stability, requiring individual stability studies for each formulation 3, 4