Evidence-Based Beyond-Use Dates for Pentravan® Compounded Formulations in Hormone Therapy and Pain Management

This bracketed study evaluated the physicochemical stability and microbiological safety of 12 compounded transdermal formulations containing clonazepam (1.0 and 50.0 mg/mL), diclofenac sodium (10.0 and 100.0 mg/mL), estriol (0.1 and 20.0 mg/mL), lidocaine (5.0 and 100.0 mg/mL), melatonin (0.5 and 50.0 mg/mL), and testosterone (5.0 and 100.0 mg/mL) in Pentravan®. Formulations were stored at room temperature for up to 180 days and analyzed at predefined intervals for active pharmaceutical ingredient (API) content, pH, visual characteristics, and antimicrobial effectiveness testing (AET). Most formulations maintained API content within the acceptable range of 90-110% throughout the study, with pH values demonstrating negligible fluctuations. Physical characteristics remained stable over time, with the exception of the diclofenac sodium 100.0 mg/mL formulation, which exhibited phase separation after 30 days. Antimicrobial effectiveness testing confirmed sufficient preservative efficacy for all formulations against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, and Aspergillus brasiliensis. The following beyond-use dates (BUDs) were established based on chemical and microbiological stability: 180 days for most APIs; 120 days for lidocaine (5.0 and 100.0 mg/mL); and 60 days for melatonin (0.5 mg/mL). These results reinforce the reliability of Pentravan® as a transdermal vehicle, demonstrating its ability to support stable and microbiologically safe formulations across a wide range of active compounds.