Spray drying is one of the most frequently used solvent-based processes for manufacturing amorphous solid dispersions (ASDs). However, the resulting fine powders usually require further downstream processing when intended for solid oral dosage forms. In this study, we compare properties and performance of spray-dried ASDs with ASDs coated onto neutral starter pellets in mini-scale. We successfully prepared binary ASDs with a drug load of 20% Ketoconazole (KCZ) or Loratadine (LRD) as weakly basic model drugs and hydroxypropyl-methyl-cellulose acetate succinate or methacrylic acid ethacrylate copolymer as pH-dependent soluble polymers. All KCZ/ and LRD/polymer mixtures formed single-phased ASDs, as indicated by differential scanning calorimetry, X-ray powder diffraction and infrared spectroscopy. All ASDs showed physical stability for 6 months at 25 °C/65% rH and 40 °C/0% rH. Normalized to their initial surface area available to the dissolution medium, all ASDs showed a linear relationship of surface area and solubility enhancement, both in terms of supersaturation of solubility and initial dissolution rate, regardless of the manufacturing process. With similar performance and stability, processing of ASD pellets showed the advantages of a superior yield (>98%), ready to use for subsequent processing into multiple unit pellet systems. Therefore, ASD-layered pellets are an attractive alternative in ASD-formulation, especially in early formulation development at limited availability of drug substance.

Background/Objectives: Neurogenic detrusor overactivity (NDO), caused by spinal cord injury or multiple sclerosis, is marked by involuntary bladder contractions and reduced urine volume. Current therapy requires frequent catheterization with oxybutynin hydrochloride. This work investigates a novel in situ forming implant (ISFI) with PLGA as a sustained-release formulation for the urinary bladder by quantifying drug release, polymer degradation, and solvent release in vitro. Methods/Results: Various formulation parameters were investigated, of which the drug load and PLGA termination were found to have the highest impact on drug release and polymer degradation. An increase in drug load from 1.5% to 7.5% for implants with the ester-terminated PLGA enhanced the degradation from 0% to around 20% after 7 d. Oxybutynin base catalyzed the polymer degradation, as implants with PLGA 502 and 15% drug load exhibited a degradation of 33% compared to 0% for 1.5% drug load. In the case of 1.5% drug load, the degradation could be increased by the use of an acid-terminated PLGA, compared to an ester-terminated. Conclusion: In summary, the feasibility of a biodegradable ISFI for NDO patients was shown, which could allow a single administration up to approx. one week, improving the quality of life for NDO patients. Additionally, this work provided insight to which formulation parameters can help to parallel drug release and polymer degradation.