Noninhalable

Noninhalable describes substances, powders, or formulations that are not intended to be administered by inhalation or that are not capable of delivering a meaningful dose through the respiratory tract. In pharmacology and toxicology, products are categorized by route of administration; noninhalable forms are designed for oral, topical, transdermal, ocular, or parenteral use, rather than for inhalation through an inhaler, spray, or nebulizer. The term is also used in occupational health to distinguish materials unlikely to become respirable dust under normal handling.

A key factor is particle size and formulation. Inhalable materials can enter the nasal or oral passages and, for some applications, reach the lungs; particles larger than about 100 micrometers in diameter are generally not inhalable in typical exposure scenarios. Conversely, respirable particles are usually in the 1–5 micrometer range and are targeted for pulmonary delivery in inhalation therapies. Noninhalable products typically comprise solids that are too large to aerosolize, or liquids and semi-solids meant for ingestion or topical use rather than inhalation.

Common examples of noninhalable products include tablets, capsules, most liquids intended for oral use, ointments, creams, gels, transdermal patches, and injectable or ophthalmic preparations. It is important to note that accidental aerosolization or grinding of a noninhalable product can create inhalable dust or aerosols, potentially posing respiratory risks. In product development and safety assessments, the designation helps guide appropriate handling, labeling, and exposure controls.