Storing Insulin in a Clay Pot in the Desert Causes no Loss of Activity: A Preliminary Report

Abstract

The biological activity of insulin, like any protein, is affected if stored at extremes of temperature. The older, acidic form of insulin required refrigeration at 2 to 8°C, but the newer neutral formulation is much more stable at room temperature (15-30°C).1,2 Manufacturers recommend storing insulin under cool, shaded conditions, neither of which is available in the desert, where temperatures frequently exceed 40°C, thus constituting a major problem for diabetic patients. The possibility of adverse side effects due to heat-induced breakdown of products must also be considered. The purpose of our study was to demonstrate the possible effect on the bioactivity of insulin, following storage in a zeer, a. semiporous clay pot containing water, in desert conditions. The small amounts of water that slowly seep through the walls of the zeer evaporate, using up heat, thereby cooling the remaining water. This principle is widely used in the Middle East to cool drinking water in such containers. Materials and MethodsEight physicians, aged 25-60 years of age (median age 45 years), volunteered and gave informed consent to participate in the experiment. All were healthy individuals free of any systemic diseases, and not on medications. They were allocated to the trial using a block design, which allowed partial double-blinding. Block 1 consisted of the four males and block 2 of the four females. For block 1, pre-storage insulin was used as the standard (reference) at the start of the experiment, thereby precluding blinding of both subjects and experimentors. For block 2, the reference insulin was that stored in a refrigerator at 4°C. For block 2, both the reference and zeer insulins were available at the same time, and their order of use was randomized using a coin toss. Both subjects and experimentors were blinded to the allocation in block 2. Insulin Storage ConditionNeutral human insulin was used and stored in a refrigerator at 4°C or in a zeer. This is a clay pot that is unglazed, enabling water to slowly seep through the wall and evaporate, thus lowering the temperature of the remaining water. The zeer used to store the insulin had an internal diameter of 30 centimeters and a height of 30 centimeters. A glass jar was partially filled with desert sand and put in the center of the insulin zeer. A water bath was created by adding water outside the jar to the same level as that of the sand in the glass jar. Water was added to the mark (topped up) daily from a larger water storage zeer. The zeer was closed with a clay lid and kept in the shade. An exact replica, but without water (a dry zeer), was also used to store insulin and record temperatures. Additional bottles of insulin were kept outside in the shade, in the bathroom of an air-conditioned house and in a refrigerator. A small amount of insulin (10 units) was removed twice daily from each insulin vial to simulate actual usage conditions. Temperature readings were taken on 12 separate occasions during the six-week storage period (Table 1). Insulin Sensitivity TestThe pr...

ISPAD Clinical Practice Consensus Guidelines 2018: The delivery of ambulatory diabetes care to children and adolescents with diabetes

“…Insulin pump users should be taught to change the insulin in the reservoir more frequently, for example, on a daily basis, when the temperature is above 30°C. In areas where ambient temperatures may be as high as 45°C to 48°C, and where refrigeration is not available, insulin can safely be stored in local cooling devices with which temperatures of about 25°C to 26°C can be achieved . Poor glycemic control may be due to using insulin that has lost its potency, but this is often overlooked.…”

The delivery of ambulatory diabetes care to children and adolescents with diabetes

“…Easy access (24 h a day) for rapid diagnosis and initiation of treatment with availability of written protocols for management of diabetic ketoacidosis (DKA) and other presentations of childhood diabetes . Provision of practical care guidance at diagnosis includes the education required to enable the family to feel confident to provide diabetes care at home and have a basic understanding of the pathophysiology of diabetes and its treatment.…”

Insulin storage in hot climates without refrigeration: temperature reduction efficacy of clay pots and other techniques

“…This requirement is a challenge for many thousands of families in low-and middle-income countries with hot climates, who do not have home refrigeration [10][11][12][13][14][15][16][17][18][19][20][21]. The International Diabetes Federation (IDF) Life for a Child (LFAC) Index study [21] reported that, in 30 of 37 low-and lower-middle income countries, at least 33% of families with children with diabetes did not have a home refrigerator.…”

“…Sometimes a solution is a neighbour's or local shop's refrigerator [10,11,13,17]. In many other cases in Africa, Asia and the Caribbean, insulin is stored in water-filled clay pots or other traditional storage devices, of various designs, using evaporative cooling [10][11][12][13][14][15][16][17][18][19][20]. Such clay pots ('zeer' pots, 'matka') are traditionally used in hot climates to keep water and foodstuffs cool [24,25].…”