Bacteriostatic water differs from sterile water by the addition of benzyl alcohol as a preservative with a final concentration of 0.9%. Benzyl alcohol can be a topical irritant but in the concentration of 0.9% does not typically cause irritation and may provide some anesthetic effects. I could not find any recommendation against benzyl alcohol being used with omalizumab. In fact, several large molecule therapeutics, such erythropoietin and granulocyte monocyte colony stimulating factor, are generally administered in solution with benzyl alcohol (Gokarn).
In summary, in my opinion there would be no problem in utilizing bacteriostatic water instead of sterile water for reconstituting omalizumab if sources of sterile water are not available.
I hope this helps in the management of your patients.
Gokarn, Yatin R., et al. "Excipients for protein drugs." Excipient development for pharmaceutical, biotechnology, and drug delivery systems 291 (2006).
All my best.
Dennis K. Ledford, MD, FAAAAI