Spray Drying for Pharmaceutical Raw Materials: A Systematic Review on Enhancing Bioavailability and Stability

Spray drying is extensively utilized in pharmaceutical development because of its scalability, cost-effectiveness, and capacity to customize solid-state characteristics. This systematic review (PubMed and Scopus, 2021-2025) assesses the impact of spray drying on the bioavailability and stability of active pharmaceutical ingredients (API) and natural products within solid dispersions (SD), solid self-nanoemulsifying drug delivery systems (S-SNEDDS), and microencapsulation. A total of 27 qualifying studies were identified and offered quantitative comparisons with untreated controls. SDs yielded AUC enhancements of 9-20-fold (eg, oxyberberine approximately 9-fold, quercetin approximately 20-fold) and dissolution improvements of 2-6-fold. S-SNEDDS produced AUC enhancements of 4-9.9-fold (sorafenib approximately 4.6-fold, enzalutamide approximately 7-fold, niclosamide approximately 9.9-fold). Microencapsulation enhanced oxidative stability (eg, approximately 3-fold reduction in peroxide value pepper seed oil and encapsulation efficiency of pomegranate seed oil reaching 90%). Benefits were contingent upon the carrier, especially with PVP/PVPVA, HPMC/HPMCAS, soluplus, and maltodextrin with protein systems. Spray drying provides superior scalability and particle engineering control compared to freeze or vacuum drying, while it still poses hazards of thermal and oxidative stress. Ongoing deficiencies encompass inadequate carrier comparisons, insufficient mechanistic comprehension of drying kinetics, and issues related to scale-up and regulation. This review offers mechanistic insights and a standardized approach to facilitate future formulation development.