Production and characterization of spray‐dried theophylline powders prepared from fresh milk for potential use in paediatrics

Objective This work evaluates the potential of using fresh milk to deliver theophylline to children. Methods Theophylline–fresh milk systems were prepared using different solids ratios (0 : 1–1 : 0) and three fat contents in commercial milks (low, medium and high), which were spray‐dried at different inlet air temperatures ( T inlet – 105, 130 and 150 °C). The process was evaluated for yield and the resulting powders for moisture content (MC), particle size and shape, density and wettability. Theophylline–milk potential interactions (differential scanning calorimetry ( DSC ) and FT ‐ IR ) and chemical (theophylline content) and microbiological stability of powders (shelf and in‐use) were also evaluated. Key Findings The production yield (13.6–76.0%), MC (0.0–10.3%) and contact angles in water (77.29–93.51°) were significantly ( P < 0.05) affected by T inlet , but no differences were found concerning the mean particle size (3.0–4.3 μm) of the different powders. The milk fat content significantly ( P < 0.05) impacted on the density (1.244–1.552 g/cm 3 ). Theophylline content remained stable after 6 months of storage, before extemporaneous reconstitution. After reconstitution in water, low‐fat milk samples (stored at 4 °C) met the microbial pharmacopoeia criteria for up to 7 days. No theophylline–milk components interaction was observed. Conclusion Spray‐dried milk‐composed powders may be used as vehicles for theophylline delivery in paediatrics following further characterization and in‐vivo evaluation.