A solid doxycycline HP-β-CD formulation for reconstitution (i.v. bolus) prepared by scaled-up electrospinning

In this study a new intravenous (i.v.) bolus dosage form of doxycycline was prepared by electrospinning. A tetracycline-type antibiotic with low water solubility (doxycycline (DOX)) was used with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) as solubilizer. The new solid formulation could be produced with high (~80 g/h) productivity rate using high-speed electrospinning (HSES) from a water-based precursor solution. Freeze-dried DOX-HP-β-CD was also prepared from the same precursor solution as HSES for comparison. Raman mapping showed that the amorphous DOX was uniformly distributed in the fibrous powder making precise dosing of the API possible. The new formulation's viability as an i.v. bolus product was examined with reconstitution test. The samples contained 100 mg of pure DOX (similarly to the products currently on the market). To ensure i.v. bolus applicability, the dissolution was carried out in 1.5 mL water. The final DOX concentration was 66.7 mg/(mL solvent), which is 7 times higher than the currently marketed formulation. The drug release was followed by UV-VIS spectrophotometry. The results confirmed that the reconstitution solution could be applied as an i.v. bolus dosage form. Moreover, the work confirmed that the continuous high-speed electrospinning process can be a viable high productivity alternative to freeze-drying.