Lasers Transform Drug into More Useful Form

Exposure to laser light may make one type of anti-inflammatory drug more effective.

Researchers at Osaka University used lasers to induce selective crystallization of the metastable form of indomethacin. The exposed drug remains in that form for up to eight months in air at room temperature. Previous research achieved metastability for less than a day.

Active pharmaceutical ingredients that can change their form — a trait known as polymorphism — are highly sought after in drug development because different polymorphic forms of the same drug have different characteristics.

The metastable phase of indomethacin is more soluble than the stable phase. Because solubility enhances drug circulation in the body, it is desirable to keep indomethacin in its metastable phase. This is difficult because the drug naturally reverts to its stable phase.

Metastable indomethacin crystallizes when supersaturated in solution. The researchers generated cavitation bubbles by focusing laser irradiation near the side wall of glass vials containing in an acetonitrile-indomethacin solution. The bubbles, in turn, enhanced the nucleation and crystallization of the metastable phase.

The research was published in Applied Physics Express (doi: 10.7567/APEX.8.045501).

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A new technique uses laser irradiation to generate crystallized metastable-phase indomethacin, lending great bioavailability to the anti-inflammatory drug. Courtesy of the Japan Society of Applied Physics.