The storage conditions and shelf life of L-Alanyl-L-cystine are influenced by multiple factors. Below is a detailed analysis:
I. Storage Conditions
1. Temperature
In general, L-Alanyl-L-cystine should be stored in a cool environment, with an ideal storage temperature of 2°C - 8°C. Within this temperature range, the rate of chemical changes is effectively slowed, ensuring stability and preventing degradation or deterioration.
If the storage temperature is too high, exceeding 30°C, the molecular activity of L-Alanyl-L-cystine may increase, accelerating its reaction with oxygen and other substances in the air. This can lead to structural changes, affecting its quality and efficacy.
On the other hand, if the temperature is too low, below 0°C, any moisture present in L-Alanyl-L-cystine may freeze, and the formation of ice crystals could damage its crystalline structure, negatively impacting its quality.
2. Humidity
L-Alanyl-L-cystine is sensitive to humidity and should be stored in a dry environment, with a recommended relative humidity of 40% - 60%.
Excessively high humidity may cause L-Alanyl-L-cystine to absorb moisture from the air, leading to deliquescence. This not only alters its physical state but may also trigger chemical reactions and promote microbial growth, significantly reducing its shelf life.
Conversely, if the humidity is too low, L-Alanyl-L-cystine may lose its crystal water, making its structure unstable.
3. Light Exposure
L-Alanyl-L-cystine should be protected from direct sunlight and strong light exposure by storing it in light-shielded containers or environments. High-energy light, such as ultraviolet rays, may induce photochemical reactions, causing chemical bond breakage or structural isomerization, which can reduce or even eliminate its activity.
4. Packaging
L-Alanyl-L-cystine should be sealed to prevent exposure to air. Contact with oxygen can lead to oxidation, causing degradation.
The choice of packaging materials is also crucial. Glass bottles or aluminum foil bags with good barrier properties are commonly used to ensure storage quality.
II. Shelf Life
Under the recommended storage conditions, the shelf life of L-Alanyl-L-cystine is generally 24 to 36 months. However, improper storage, such as high temperatures, excessive humidity, or prolonged light exposure, may significantly shorten its shelf life to just a few months or even less.
Additionally, once the packaging is opened, the risk of contamination and deterioration increases due to greater exposure to the external environment. Therefore, it is recommended to use the product as soon as possible after opening and ensure it is properly sealed after each use.
