phosphate buffered saline

Phosphate Buffered Saline (PBS) is a sterile, physiological salt solution used as a placebo control in clinical trials, specifically within Vical's development program for pandemic influenza DNA vaccines. In the Phase 1 study (NCT00471133), PBS was administered via intramuscular injection using the Biojector 2000 needle-free system to healthy volunteers. It serves as a pharmacologically inert comparator to evaluate the safety and immunogenicity of active investigational products such as VCL-IPM1 and VCL-IPT1. The solution typically contains sodium chloride and phosphate salts to maintain a stable pH and osmotic pressure consistent with human biological fluids.