ASO Co., Ltd.

 This section explains what insoluble particles are, their causes in pharmaceutical manufacturing, and specific countermeasures to prevent contamination risks.

 Insoluble particles are fine solid substances that do not dissolve in liquids and either remain suspended or settle.
 In pharmaceutical manufacturing, contamination with insoluble particles is a critical quality concern.
 For high-cleanliness products, such as injections or ophthalmic solutions, particle control is an essential quality consideration.

Insoluble particles that may arise during pharmaceutical manufacturing can be broadly classified into the following two categories:

・Polymer particles
These are particles generated from the resin itself, such as polyethylene, due to processing or friction.
 Their occurrence tends to increase when using low-grade resins or recycled materials.

・Additive particles
These are particles derived from additives, such as slip agents or antioxidants, which are used to impart flexibility or processability to polybags.
 These additives may precipitate or separate during use, appearing as insoluble particles in the final product.

The following table summarizes representative types and countermeasures:

Insoluble particles are often visible as foreign matter and can lead to shipment suspension, product recalls, or customer complaints.
 For sterile injections and ophthalmic solutions, strict regulations apply (e.g., Japanese Pharmacopoeia “Test for Insoluble Particles”), and even a single vial exceeding the limit may result in the disposal of the entire production lot.

"Use of additive-free polybags"
Since additives such as slip agents are a potential source of particles, there is increasing demand for additive-free polybags.
 Using additive-free films prevents additive-derived particle generation at the source and minimizes contamination risks.