Infant Formula-Based Oral Lyophilizates for Personalized Pediatric Drug Delivery: Development of Flexible-Dose Loratadine Formulations and In Vivo Evaluation

Age-appropriate dosage forms with flexible dosing remain a challenge in pediatric pharmacotherapy. This study investigated infant formula-based oral lyophilizates containing loratadine at doses of 5 mg and 10 mg, prepared using different fill volumes (0.2-0.5-1.0 mL). The formulations were evaluated for disintegration, mechanical properties, in vitro dissolution, particle size, thermal behavior and morphology. A preliminary pharmacokinetic study in Wistar rats compared a reconstituted lyophilizate with a conventional loratadine suspension. All formulations disintegrated within 6.21 s, and more than 97% of loratadine dissolved within 15 min. Differential scanning calorimetry revealed similar glass transition temperatures in the frozen milk-based suspensions (−21.71 °C to −22.31 °C), supporting the selection of primary drying conditions. Thermal and morphological analyses indicated changes in loratadine behavior following incorporation into the freeze-dried matrix. In vivo, systemic exposure was comparable between the lyophilizate dispersion and the reference suspension, with AUC_0–∞ values of 17.39 ± 10.14 and 18.21 ± 6.69 µg·h/mL, respectively. These findings support the potential of infant formula as a matrix for flexible-dose oral lyophilizates with loratadine.