Development and characterization of novel fast-dissolving pentobarbital suppositories for pediatric procedural sedation and comparison with lipophilic formulations

For pediatric radiological procedures (RP), pentobarbital sodium (PNa) can be used orally or rectally to replace intravenous anesthesia. Since no commercial PNa suppositories exist, they must be prepared by compounding pharmacies. This study aims to develop fast-dissolving PNa suppositories for fast pharmacological activity during RP. We prepared gelatin (G), gelatin/polyethylene glycol 4000 (GP), and polyethylene glycol 4000 (P) suppositories, with and without pH adjustment, and assessed their dosage uniformity (DU), softening time, rupture resistance, and in-vitro dissolution. An optimal formulation was selected, and PNa release was compared to that of fat-based suppositories using dissolution tests. Additionally, the quality control process (analytical performance, safety/eco-friendliness and productivity/practical effectiveness) of these formulas were compared using a RGB method. All hydrophilic formulas (HF) met the DU requirement (AV < 8 %) except for P (AV 15.62 ± 4 %). pH adjustment enhanced G and GP suppositories resistance to 2.2 ± 0.2 kg and 2.0 ± 0.3 kg, respectively, and allowed 100 % release of PNa in under 10 min. In contrast, lipophilic formulas released less than 80 % of PNa at best after 120 min. These results show the biopharmaceutical suitability of HF for RP compared to lipophilic ones, but a pharmacokinetic study is needed to confirm data.