Overcoming the Challenges of Color Measurement in Coated Pills

hand with coated pills
Changing a pill’s color can make users less likely to take needed medication. Image Source: Shutterstock user White bear studio

The color of coated pills isn’t just about aesthetics—it can impact how consumers identify and use medications. For example, the authors of one study on the impact of pill appearance on consumer perception noted that a “change in the shape or color of medications may contribute to patients’ stopping treatment.”1 This may be in part because users depend on the color of the pills to tell them what to take and when, as many users identify their pills by their color rather than their name. Pharmaceutical companies also increasingly employ color to protect against counterfeiting, a major issue as the $431 billion counterfeit pill industry continues to grow.2  Due to the critical role of color plays in pharmaceutical use for both consumers and companies, color management becomes an essential part of the overall quality control process.

However, working with coated pill samples can bring up a number of difficulties. Of particular concern is being able to analyze a sizable representation of a batch and gain accurate data from a non-uniform sample surface. Choosing the correct spectrophotometric instrumentation is necessary to overcome these challenges and obtain meaningful data from color measurement.

coated pills color measurement
Some spectrophotometers are not designed to handle non-uniform samples, preventing rapid color measurement of coated pills. Image Source: Shutterstock user Wanannc

The Challenges of Color Measurement in Coated Pills

Pill color has always been an essential component of medicine. In the Middle Ages, some would even coat pills in silver and gold to make them more aesthetically appealing. However, these individuals learned the hard way that adding a coating to tablets can make the medicine inert, as the old silver and gold coverings kept them from breaking down in the patient’s digestive tract.3 Today, pill manufacturers are much more careful about how their coatings can impact the efficacy of medicine. These coatings are carefully created to ensure they will dissolve easily and quickly so users can get the maximum benefit out of their medications.4 There is a wide variety of coatings that manufacturers may use, resulting in an extensive range of color combinations.  Even as the manufacturers decide to update their coatings, they need to ensure the color of a specific medication remains consistent.

The nature of pills themselves, however, present a number of unique challenges to the spectrophotometric color measurement process:

  • Non-Uniform Samples: Even the largest of pills does not have a big enough surface to measure color with a spectrophotometer that requires direct contact. This means that accurate analysis of color requires using a non-contact spectrophotometer to measure multiple pills at once in order to obtain meaningful color data. However, samples made up for multiple pills are inherent non-uniform, which means many spectrophotometers are not able to accurately analyze sample color without significant sample preparation.
  • Sample Size: In order to ensure that a sample is representative of the batch as a whole, multiple pills should be measured simultaneously. However, many spectrophotometers are not designed to measure large samples, which may mean that operators must use a larger number of samples or that they take the risk of allowing a very small number of pills represent the whole batch.

In the past, overcoming these challenges often required laborious workarounds, relying on extensive sample preparation and leaving the process open to human error. Today, however, advances in technology have resolved these issues, ensuring that manufacturers can take advantage of objective color measurement.

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 Finding the Right Spectrophotometer



The ability to rapidly and efficiently measure the color of pills is vital to manufacturers, but sometimes, there are limitations in the color measurement technology available. To ensure that they’re able to manage the challenges that come with measuring these samples, manufacturers should opt for non-contact instruments designed to handle non-uniform samples. The HunterLab Aeros, for example, is engineered specifically to analyze irregularly shaped and textured samples. Part of what makes this possible is automatic height positioning; by automatically adjusting the height of the sensor, the Aeros ensures that measurements are taken from an optimal position. This not only allows you to obtain the most accurate results, it also reduces sample preparation time, eliminates the need for human intervention, and reduces the potential for human error and operator inconsistencies.

The Aeros is also designed to handle large samples of pills; in fact, it has the largest sample area measurement of any spectrophotometer in the world, ensuring that you are able to analyze a meaningful sample size for more reliable insight into your batch. In order to obtain color information, the Aeros uses a rotating sample platform that spins while the instrument takes 35 measurements within 5 seconds and automatically averages the data. This gives you unprecedented accuracy and precision of measurement while reducing labor and measurement time. Additionally, increased color accuracy and consistency help maintain the colors pharmaceutical companies rely on to reduce counterfeiting risk and promote patient safety.

The measurement features of the Aeros make it ideally suited to analyze the color of coated pills rapidly and reliably. However, the benefits of the Aeros go beyond its basic measurement capabilities. With an intuitive, digital touchscreen display and onboard EasyMatch Essential software, the Aeros is designed to be a user-friendly instrument that allows operators to easily capture, display, and analyze data. Smart communications features mean data can be instantly shared via emailed or streamed to LIMS and SPC systems. Additionally, the Aeros uses sealed motor compartments and optics to increase durability and comes with HunterLab’s innovative Remote Access Support services for ongoing support.

HunterLab Technology

If you’re ready to take your pill color measurement process to the next level, HunterLab can help. Contact us today to learn more about the Aeros, as well as our comprehensive range of benchtop, online and portable instruments. We’re always happy to answer any questions and help you connect with the tools you need to improve the quality of your products and efficiency of your production.
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  1. Changing a pill’s color has big health consequences”,  https://www.vox.com/2014/7/17/5912503/changing-a-pills-color-has-big-health-consequences
  2. “Deadly fake Viagra: Online pharmacies suspected of selling counterfeit drugs”, August 31, 2015. http://www.cnn.com/2015/08/31/health/counterfeit-medications/
  3. “The Colorful History of Pills Can Fill Many a Tablet.” March 25, 2002. http://articles.latimes.com/2002/mar/25/health/he-booster25
  4. “Different Coatings.” http://swallowingdifficulties.com/patients/what-is-a-tablet/different-coatings/