Industry Articles
Role of Phase Change Materials for Safe Transportation of Pharmaceutical Goods
Author: Samit Jain, Pluss Advanced Technologies
| Update : 21st November, 2022 |
Over 25% of vaccines reach their destination degraded because of incorrect shipping. 30% of scrapped pharmaceuticals can be attributed to logistic issues alone. 20% of temp-sensitive products are damaged during transport due to broken cold chain. Shelf life of the sensitive medicinal products is short and demands temperature control.
As per WHO, precise temperature conditions has to be specified on the every product. The labels and precautionary statements range from “store under normal storage conditions (15 to 25°C)”, “store between 2 and 8°C (under refrigeration, no freezing)”, “store below 8°C (under refrigeration)”, “store between -5 and -20°C (in a freezer)” to “store below -18°C (in a deep freezer)”.
The products therefore require speedy and temperature controlled delivery of the products. Any temperature fluctuations can make the product unstable and unfit to use. Products travel from hot and humid to cold and dry climate. Simply boxing the pharmaceutical products does not help solve this problem. Moreover, temperature tracing up to last mile delivery is not a usually followed practice. This raises questions on reliability of tertiary packaging used and whether it can really sustain temperature abuse on outside during the transportation.
The paper presents the role of Phase Change Materials and a box design for transporting such temperature sensitive goods. The box maintains the temperature inside the payload box within range throughout its journey; from the manufacturer’s pick up point to the end customer.
Introduction
Over 25% of pharmaceutical products are wasted every year during the transportation. Since seven out of ten pharma products require temperature-controlled shipping, compromised temperature-controlled chain has emerged as one of the leading causes of this wastage. The products, therefore, require speedy and temperature-controlled delivery of the products2. The reality, however, is pharmaceutical supply chain is quite complex and fragmented. There are multiple stake holders and intermediaries through the entire process; a single miss can result in damaged products putting lives of patients at risk. All is not that bad though. Recent innovations and technological advancements have made it much easier to mitigate such risks today.
We will discuss the role of one such innovation- phase change materials, or PCMs as they are commonly called, using an experimental box design. PCMs are suited to meet the specific temperature requirements. Several organizations have explored, implemented and commended the kind of problems PCMs could solve for the industry. Today, all major pharma packaging companies are focusing on improving the packaging design and performance by incorporating different kinds PCMs suiting different requirements. Choice of right PCM, insulation and packaging has become the most important parameter while designing a temperature-controlled transportation box. Companies like Pelican Biothermal, Sonoco Thermosafe, va-Q-tec and PLUSS (India) are all focussed on delivering right temperature, universal packing, and compact size using PCMs and VIPs (Vaccum Insulation Panel).
What are PCMs and why are they used?
Phase Change Materials (PCMs) are passive thermal energy storage materials, meaning they can maintain temperature without any external power supply. This is achieved by energy involved in change of phase from solid to liquid or vice versa. The most commonly used PCM is water/ice (gel). However, its efficacy as PCM has always been in question. Melting at 0°C (32°F), use of water is mostly imprecise for pharmaceutical products and adds to the risk of freezing the vaccines. Three major factors that qualify a PCM are:
- Consistency in performance over a substantial number of cycles
- Constant temperature maintenance during release and absorption of energy
- High latent heat energy storage capacity
PCMs were developed to meet the ever-increasing energy needs in the field of cooling and heating, including in pharmaceutical product shipments. Today, specific PCMs between the range of -35°C to +89°C exist for maintaining precise temperatures. This helps maintaining the integrity of the temperature-sensitive products. Some of the advantages of PCMs over regular water/ice pouches are:
- Help maintain the product integrity - PCM used for maintaining 15–25°C temperature is different (has different melting temperature) than the one used for maintaining 2–8°C temperature or for frozen (-20°C) products
- Allow for reduced packet size, weight and volume
- Drive costs lower - with high energy PCMs lower cost insulation can also deliver adequate performance. Make much simplified packaging
Material of Construction
An insulated box was constructed with thermal resistance in the range 2–3 m2K/W. Payload box to accommodate the pharmaceutical goods was also constructed with an insulation material with low thermal resistance in the range of 0.3 – 0.6 m2K/W. Phase change material (PCM) with phase change temperature of 1°C, 22°C and -23°C was chosen to maintain the box temperature in the range of 2-8°C, 15–25°C and -15 to -25°C, respectively. PCM combinations for each range of temperature is shown in Table 1.
| Temperature Range (°C) | PCM1 Phase change temperature (°C) | PCM2 Phase change temperature (°C) |
|---|---|---|
| 2-8 | 1 | 5 |
| 15-25 | 22 | - |
| -15 to -25 | -23 | - |
Table 1: PCM used for different temperature range of PCM
To ensure that the temperature does not go below the desired range, a second PCM is aligned along the walls of the payload box. PCM properties of all the PCMs used in the transportation boxes is shown in Table 2. Aligning the second PCM along with the first PCM is termed as cascaded effect. Presence of second PCM ensures that the extra energy stored by the first PCM does not go waste and also ensures that the pharmaceutical products are not affected by the subzero temperature. Secondly, frozen PCMs do not need any conditioning time. PCM materials used in the boxes are water based or biodegradable products which does not affect the environment in the long run.
| PCM | Phase Change Temperature Range (°C) | Latent Heat (kJ/kg) | Density g/cc |
|---|---|---|---|
| HS01 | 2-8 | 340 | 0.99 |
| HS22 | 15-25 | 185 | 1.54 |
| HS23N | (-20)-(-25) | 290 | 1.2 |
| OM05 | 5-10 | 250 | 0.9 |
Table 2: PCM properties
To ensure the longevity of the box up to two to three uses and to protect the pharmaceutical products from condensate of the frozen PCM pouches, appropriate packaging was chosen. Pharmaceutical products are first enclosed in their individual packaging as produced by the manufacturer. The payload box is made of an insulating material (polyurethane foam, expanded polystyrene or vacuum insulated panels). The packaged pharmaceutical products go into the payload box. Each PCM pouch used to maintain the temperature of the box is enclosed in a corrugated box to give the whole assembly a rigid structure. An exploded view of one such box is shown in Figure 1.
Methodology
Special care was taken in this design to make the product user-friendly. The box assembly is similar to stacking a carton over carton. This reduces the chances of error at the freight forwarder.
Figure 1: Exploded view of the transportation box
To check the accuracy of the box, it was tested under two conditions:
- An optimum temperature of testing was determined from Table 3. To do this, the temperature profiles in Table 3 were analysed. As a worst case scenario, the box was placed at an averaged-out temperature throughout the experiments.
- Real-time testing. To do this, the temperature-controlled chamber was programmed with temperature and time data as per Table 3. The box was then placed inside the chamber.
| Exposure temp (°C) | Exposure time (hours) | Movement from Hyderabad |
|---|---|---|
| 5 | 10 | Reefer truck (from freight forwarder to shipper) |
| 25 | 4 | Shipper |
| 5 | 10 | Reefer truck to airport |
| 35 | 2 | Airport unloading before it reaches CFE |
| 5 | 12 | CFE |
| 45 | 4 | Del. tarmac |
| 5 | 10 | In-flight |
| 40 | 3 | Unloading during transit, tarmac (Istanbul) |
| 5 | 10 | CFE |
| 40 | 3 | Loading during transit; tarmac (Istanbul) |
| 5 | 10 | In-flight |
| 30 | 3 | Destination unloading, tarmac (US) |
| 25 | 15 | Destination airport |
| 5 | 8 | Reefer truck |
| 30 | 2 | Unloading at destination warehouse |
Table 3: : Temperature profile for real-time testing
Experimental Results
- A transportation box was loaded with HS01 and OM05. HS01 was frozen before assembling the box. OM05 was lined along the walls of the payload box. The payload box was loaded with medicines. The complete assembly was placed in an ambient 32°C. The performance of the box over the next 120 hours is shown in Figure 2.
- Real-time testing. The box was again loaded with HS01 and OM05. HS01 was frozen before assembling the box. OM05 was lined along the walls of the payload box. The payload box was loaded with medicines. The temperature-controlled chamber (used as an ambient) was programmed according to the profile shown in Table 3. The complete assembly was placed in the chamber. The performance of the box over the next 120 hours is shown in Figure 3.
Figure 2: Performance of 2–8 degree box when placed at an ambient 32°C
Figure 3: Real-time testing
Conclusions
Pharmaceutical products and other temperature sensitive goods need utmost precision in storage and transportation. PCM technology is a boon to such products. However, appropriate assembly and packaging is equally important. Poor design can lead to compromised performance and/or higher cost. Unnecessary and unplanned packaging can lead to extra weight of the box leading to extra freight charges. Extra or less amount of PCM can also drastically affect the performance of the box. This transportation box is a result of exhaustive optimization of right quantity of PCM and packaging. Optimized deadweight reduces freight cost.
The results can be extrapolated to develop pallet shippers. For pallet shippers, back up hours can go upto five days providing a great bulk shipping option at controlled temperature. The solution can be beneficial and economical for the pharmaceutical logistics. The wastage of medicines and vaccines can be curbed to a large extent reinforcing our commitment of providing quality healthcare and ensuring well-being of every individual.
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About Pluss Advanced Technologies
PLUSS Advanced Technologies, located in New Delhi, India, was founded in 1993 and started with R&D and manufacturing of specialized polymers. In 2006, PLUSS commenced development in the field of Phase Change Materials (PCMs) Technology. In 2012-13, PLUSS received equity funds infusion from Tata Capital Innovations Fund which has helped the company expand its resources and further strengthen its R&D and manufacturing capabilities.
Source : Pluss Advanced Technologies
