Drying Method Selection as a Critical Determinant of Pharmaceutical Quality in Biotherapeutic Lucilia sericata Larval Extracts

Objectives: This study aimed to compare the preservation efficacy of protein content and antioxidant activity in crude whole-body larval extract (WBE) products obtained from Lucilia sericata second instar (L2) larvae using four different drying protocols. Methods: The larvae were processed using lyophilisation (freeze-drying), infrared drying, microwave drying, and conventional oven drying methods. The antioxidant capacities (using the DPPH radical scavenging and FRAP iron reduction methods) and total protein concentrations (using the Bradford and Lowry methods) of the resulting extracts were then analysed. Statistical analyses (one-way ANOVA, Tukey HSD test, p<0.05) revealed that drying methods had a highly significant effect on the results. Findings: The highest antioxidant activity (DPPH: IC₅₀: 0.1350 ± 0.0242 mg/mL; FRAP: 45.4430 ± 0.0037 mg TE/g) and protein content (237.1 ± 0.0203 mg/ BSA eq/g dry weight (Bradford method), 164.8125 ± 0.0056 mg/BSA eq/g dry weight (Lowry method)) were observed in the lyophilisation group. This group was followed by infrared drying, which showed moderate values (DPPH: IC50: 0.2546 ± 0.0341 mg/mL; FRAP: 40.1603 ± 0.0082 mg TE/g; Protein: 173.0378 ± 0.0060 mg/BSA eq/g dry weight (Bradford method), 144.4583 ± 0.0065 mg/ BSA eq/g dry weight (Lowry method), followed by oven drying with significantly lower values, and microwave drying with the lowest bioactivity. The findings clearly demonstrate that the duration and intensity of thermal stress have a direct degradative effect on heat-sensitive proteins and antioxidant molecules in the larvae. Novelty: Drying methods have a significant effect on the bioactivity of larval secretions and have implications for Larva Debridement Therapy (LDT) applications. The stability of bioactive compounds responsible for wound healing and antimicrobial properties is critical in these products. By demonstrating that lyophilisation preserves up to four times more protein content and significantly higher antioxidant capacity than conventional thermal methods, this research offers a standardized, evidence-based protocol for the industrial-scale production of high-quality, bioactive larval extracts. This advancement directly addresses the critical bottleneck of biomolecule degradation during processing, paving the way for more stable, accessible, and potentially efficacious pharmaceutical products for LDT; confirmation of therapeutic efficacy will require further functional, antimicrobial, and in vivo assays. Keywords: Lucilia sericata, biotherapy, drying optimisation, thermal degradation, antioxidant capacity, protein stabilisation, lyophilisation, infrared drying