Impact of Storage Conditions on Shelf Life Determination in Pharmaceuticals

Introduction:

Since 1979, the Food and Drug Administration (FDA) has announced that all prescription drugs should have a shelf life or expiration date mentioned directly on the container label. Shelf life is regarded as the time period for which a drug product can be stored or consumed if it is stored under the conditions defined on the container label.

It is essential to gain information about the product and shelf life distributions. It allows us to determine the proportion of the shelf life distribution that has to be considered for estimating the product shelf life. The Product Quality Research Institute (PQRI), in 2006, established a ‘Stability Shelf Life Working Group’ that aimed to investigate current statistical methods for estimating shelf life related to the stability data. Further, the development of improved methods must be encouraged. This working group comprises regulatory, pharmaceutical, and statistical scientists from government, industry, and academics. It was soon proposed that the term “shelf life” is used to describe various concepts in the scientific literature, and no formal agreement is present for mathematically defining the shelf life.

What Are the Storage Conditions Required in Pharmaceuticals?

Drug stability usually depends on the following factors:

1. Environmental Factors:

• Temperature.

• Humidity.

• Air.

• Light.

2. Drug-Related Factors:

• Active ingredient itself.

• Dosage forms like tablets or solutions.

• Manufacturing process.

Therefore, it is essential to follow the storage instructions provided by the manufacturers on the labels.

Air and Humidity: The recommended relative humidity in a store must not exceed 65 percent, which can be measured through a variety of humidity measurement devices. Air acts as an essential factor in the deterioration of medications as it contains both oxygen and humidity. It is recommended that all containers must remain completely closed. Drugs are not exposed to air and light in opaque and airtight containers. Opening the containers prior to drug usage must be avoided. Patients must ensure to remove the tablets from blisters immediately before administration.

Temperature: The temperature in the store should not be above 25 degrees Celsius. The European pharmacopeia has defined storage temperatures as follows:

1. Freezer: - 15 to 0 degrees Celsius.

2. Refrigerator: + 2 to + 8 degrees Celsius.

3. Cool: + 8 to + 15 degrees Celsius.

4. Ambient temperature: + 15 to + 25 degrees Celsius.

Recent advancements have helped the pharmaceutical industry to maintain the potency and vitality of medicines at lower temperatures. Cold storage ranges from two and eight degrees Celsius which has become one of the most popular choices for storing pharmaceuticals. However, for this type of storage, it is essential for the manufacturer, shipper, and seller to work together to coordinate and communicate every stage of the process so that no temperature errors occur. The transit and transportation temperatures should be 50 to 60 degrees Celsius inside vehicles or shipping containers. In such cases, shelf life and expiry dates cannot be guaranteed. Freezing should also be avoided for medications that may get damaged, especially for solutions, as it may cause the precipitation of active ingredients or the breaking of vials. They are required to be stored in the refrigerator between 2 and 8 degrees Celsius, and the cold chain procedure must be followed strictly during transport.

The following products are sensitive to heat and light. Therefore they have to be stored in the refrigerator between 2 and 8 degrees Celsius:

• Vaccines.

• Immunoglobulins.

• Antisera.

The vaccine vials can have a heat-sensitive monitor (VVM). The monitor measures total exposure to heat. The monitor has a square that changes color on exposure to heat over a period of time; if the square color is lighter than the circle, the vaccine is fit for use. If the square color is the same color or darker than the circle, the vial cannot be used and must be destroyed.

• Controlled Temperature Chain (CTC): To be used in a controlled temperature chain (CTC), the vaccine should be able to tolerate temperatures of up to 40 degrees Celsius for at least three days or once out of the cold chain. The maximum temperature of 40 degrees Celsius must be monitored by a peak threshold indicator in every vaccine carrier for transport and vaccination in the field. Certain vaccines are licensed for use in a controlled temperature chain (CTC) In some mass vaccination campaigns only. It can be transported and used out of the cold chain within a specific time limit.

• Light: It is important to protect the medications from light, especially solutions. Parenteral forms must also be preserved in their packaging. Light-sensitive medications must be kept in colored glass for protection against light.

What Is the Impact of Improper Storage Conditions on Shelf Life Determination in Pharmaceuticals?

It is essential to be familiar with the routine aspects of each drug, including its color, consistency, odor, and solubility, to identify alterations that may indicate its damage or deterioration. It is essential to know that deterioration does not always cause an external modification.

The major consequence of deterioration due to improper storage is a reduction of therapeutic activity that leads to serious consequences for the individual or community. For instance, the use of expired antibiotics does not cure an infection and causes the development of strains. Certain drugs undergo deterioration over time leading to the development of substances that are much more dangerous and increasing their toxicity. For example, Tetracycline, which is a pale yellow powder, turns brownish and viscous; therefore, it is dangerous for usage even before the expiry date. Suppositories, creams, and ointments that have been melted due to heat must not be used as the active ingredient is not distributed in a homogenous manner if they are used.

Conclusion

Every pharmaceutical product has a specific storage requirement which makes it essential to ensure that storage conditions are monitored properly all the time in order to maintain quality. If a pharmaceutical product or sample is stored at a temperature that is not suitable for maintaining stability. Improper storage can lead to degradation, which could be dangerous or deadly if the product is administered. In some cases, temperature can even impact and change the properties of a medicine, causing changes in odor, color, taste, and texture. These are physical changes that indicate that the drug is not viable and does not cause harm to a consumer.