FT-IR Microinfrared Spectroscopy To Detect Particles And Impurities In Liquid Drugs

2024-02-06

In the pharmaceutical industry, FTIR technology is widely used for solid and liquid drug analysis. FTIR applications include polymorph analysis and solid-state characterization of active pharmaceutical ingredients (APIs). In addition, FTIR can quickly and efficiently identify impurities and contaminants.

Ampoules containing liquid medications that may contain impurities

Impurity Problems In Drugs

The purity of a drug is critical to ensuring its safety and efficacy. For example, the presence of particles in liquid drugs can cause physical and chemical changes in the drug formula. This may cause adverse reactions such as irritation, inflammation, or allergic reactions.

Additionally, particles can interfere with the drug's intended mechanism of action. Particles can also affect a drug's stability and shelf life, causing it to degrade or lose potency over time. To prevent these problems, the medication needs to be monitored closely. FTIR is one such monitoring tool.

Why Choose FTIR?

Optical microscopes have high spatial resolution and can observe and identify particulate matter. However, optical microscopy cannot resolve chemical composition. In contrast, FTIR microscopy not only has high spatial resolution but can also identify particles—providing comprehensive chemical information. Therefore, FTIR is recognized as a tool suitable for particle characterization.

Next, taking liquid medicine as an example, an FTIR microinfrared spectrometer is used to analyze particulate matter using a fully automatic particle testing method and a focal plane array detector method (FPA). and explore which method is more efficient.

FTIR Microscopic Infrared Fully Automatic Particle Testing Method

Analysis of antibody solutions containing contaminating particles. First, particulate matter must be separated from the liquid phase using a filtration device. Then, a microscopic infrared spectrometer is used to automatically acquire an overall image of the filter membrane with a high-resolution visual camera.

Use the Particle Finder function to detect particulate matter based on visible light image contrast. The results showed that ten particles were present in the solution. Automatic identification of measurement points for each type of particle. The detected particles are then numbered, amplified, and overlaid onto the visible light image (Figure 1).

Figure 1: Visible light image of particles on the filter membrane

The transmission mode and the OPUS Cluster ID in the software can be used to collect the infrared spectrum of each particle for fully automated testing. The chemical composition of each particle was then identified (Table 1)

Table 1: Determining the composition of detected particles by searching the database

FPA imaging method

The same antibody solution was tested using FPA imaging. This method does not use the traditional FTIR microspectroscopy method, but uses the FPA area array detector. During the test process, it can complete infrared imaging at the fastest speed, completing the entire test area in less than one minute, and the spatial resolution can reach 5 Micron/pixel.

The chemical imaging artificial intelligence algorithm can be used to process data completely autonomously and identify multiple particles (Figure 2). The fibers visible under the light microscope were identified as cellulose (pink), and the two other visible particles were identified as polystyrene particles (blue-green).

Figure 2: Visible light image of filter membrane and particulate matter (left); FTIR chemical imaging image (right)

Compared with traditional FTIR microspectroscopy, FPA imaging method can obtain more information. As shown in Figure 2, the FPA imaging method accurately detects and identifies silicone oil (red) and protein clusters (green) that are not captured in visible light photos. Particle detection and identification are based entirely on the FTIR signature of the collected particles. So there are no undetected particles.

Infrared imaging methods perfectly combine high-speed and high-resolution chemical imaging. Identification of sample chemical composition is not affected by the contrast of visible light photographs. This is the main advantage of FTIR imaging compared to optical microscopy. For the study of particles in injection solutions and particle analysis, we strongly recommend the FPA chemical imaging method.

Patients rely on medications to manage their health conditions. Therefore, it is very important to ensure the purity and quality of drugs. FTIR imaging is a valuable tool for quality control and quality assurance, and Optosky is proud to be a part of this important work.

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