Effect of Colour and Surface Properties of Solid Pharmaceutical Dosage Forms on Light Reflection in Solar Spectral...

The objective of the present study was to undertake a comparative analysis of the effect of colour, score line, embossing or printing on the surface of selected solid oral pharmaceutical dosage forms on the reflectance properties in the range of ultraviolet A, visible and near infrared radiation from 335 to 2500 nm. This analysis was carried out using the value of directional hemispherical reflectance as a parameter indicating the resistance of the pharmaceutical dosage form to solar radiation through reflection mechanism. Reflected radiation has no physical or chemical effects.

Directional hemispherical reflectance (DHR) was used in analysis. Quantitative assessment of the reflected radiation by the sample allows the determination of how much radiation is absorbed or transmitted by the tested object, thus allowing the assessment of the interaction strength of specific spectral ranges.

External parameters of the pharmaceutical dosage form, such as colour, score lines, embossing, or imprints, can determine interactions of medicinal product with electromagnetic radiation.

These findings have practical implications for pharmaceutical formulation. The results suggest that colour and surface texture should be considered when developing photostable pharmaceutical products.

• Electromagnetic radiation affect on stability of medicinal product. • Reflected radiation does not cause physical and chemical effects. • Colour and structural elements of solid pharmaceutical dosage form determine reflective properties. • Directional hemispherical reflectance (reflectance) as a measurer of exposure to radiation.