In vitro... Infasurf (calfactant) adsorbs rapidly & modifies surface tension similar to natural lung surfactant5

In Vitro Studies: Adsorption and Surface Tension*1, 2

Infasurf Chart A

  • INFASURF demonstrated activity similar to that of a natural surfactant
  • INFASURF lowered minimum surface tension to near-zero values during dynamic tension1


*In vitro and in vivo animal studies and biologic testing do not predict clinical effects


Infasurf Chart B

The Potential Role of SP-B in Surfactant Function

Biophysical studies suggest the following:

  • SP-B may enhance the surfactant’s ability to rapidly adsorb, lower surface tension, and improve lung compliance1, 3
  • Hypothesized that surfactants high in SP-B may be less susceptible to inhibitory proteins4


Protein Composition of INFASURF

Infasurf Chart C
  • INFASURF is prepared from an extract of a natural surfactant from calf lung lavage—the process preserves a natural SP-B level5
  • INFASURF contains 0.74% SP-B and 1.26% SP-C for a total protein content of 2.0% of total phospholipids5


In Vitro Protein Inhibition4

Infasurf Chart D*Up to 8mg/mL protein concentration was shown

  • Surfactant inhibition by plasma proteins was evaluated in vitro using the pulsating bubble surfactometer with surfactant concentrations between 0.1–0.2 ng/mL
  • INFASURF was shown to adsorb rapidly and lower minimum surface tension to near zero values, even when exposed to increasing levels of inhibitory proteins4
  • Fibrinogen, the most potent of inhibitory proteins, had a moderate effect on INFASURF4



Infasurf Bottles

To report adverse events or product related issues, click here.


Infasurf® (calfactant) is indicated for the prevention of Respiratory Distress Syndrome (RDS) in premature infants at high risk for RDS, and for the treatment of premature infants who develop RDS. Infasurf decreases the incidence of RDS, mortality due to RDS, and air leaks associated with RDS.


Prophylaxis therapy at birth with Infasurf is indicated for premature infants <29 weeks of gestational age at significant risk for RDS. Infasurf prophylaxis should be administered as soon as possible, preferably within 30 minutes after birth.


Infasurf therapy is indicated for infants ≤72 hours of age with RDS (confirmed by clinical and radiologic findings) and requiring endotracheal intubation.

Important Safety Information

Infasurf is intended for intratracheal use only. THE ADMINISTRATION OF EXOGENOUS SURFACTANTS, INCLUDING INFASURF, OFTEN RAPIDLY IMPROVES OXYGENATION AND LUNG COMPLIANCE. Following administration of Infasurf, patients should be carefully monitored so that oxygen therapy and ventilatory support can be modified in response to changes in respiratory status.

Infasurf therapy is not a substitute for neonatal intensive care. Optimal care of premature infants at risk for RDS and new born infants with RDS who need endotracheal intubation requires an acute care unit organized, staffed, equipped, and experienced with intubation, ventilator management, and general care of these patients.

TRANSIENT EPISODES OF REFLUX OF INFASURF INTO THE ENDOTRACHEAL TUBE, CYANOSIS, BRADYCARDIA, OR AIRWAY OBSTRUCTION HAVE OCCURRED DURING THE DOSING PROCEDURES that required stopping Infasurf and taking appropriate measures to alleviate the condition. After the patient is stable, dosing can proceed with appropriate monitoring.

An increased proportion of patients with both intraventricular hemorrhage (IVH) and periventricular leukomalacia (PVL) was observed in Infasurf-treated infants in the Infasurf-Exosurf Neonatal controlled trials. These observations were not associated with increased mortality.

The most common adverse reactions associated with Infasurf dosing procedures in the controlled trials were cyanosis (65%), airway obstruction (39%), bradycardia (34%), reflux of surfactant into the endotracheal tube (21%), requirement for manual ventilation (16%), and reintubation (3%). These events were generally transient and not associated with serious complications or death.

The incidence of common complications of prematurity and RDS in the four controlled Infasurf trials are presented in the Table. Prophylaxis and treatment study results for each surfactant are combined.

Infasurf Safety Table

1 Hall SB, Venkitaraman AR, Whitsett JA, Holm BA, Notter RH. Importance of hydrophobic apoproteins as constituents of clinical exogenous surfactants. Am Rev Respir Dis. 1992, 145:24-30.
2 Wang Z, Notter RH. Additivity of protein and non-protein inhibitors of lung surfactant activity. Am J Respir Crit Care Med 1998;158:28-35; ONY, Inc.
3 Mizuno K, Ikegami M, Chen C-M, Ueda T, Jobe AH. Surfactant protein-B supplementation improves in vivo function of a modified natural surfactant. Pediatr Res. 1995; 37:271-276.
4 Seeger W, Gruba C, Gunther A, Schmidt R. Surfactant inhibition by plasma proteins: differential sensitivity of various surfactant preparations. Eur Respir J. 1993; 6:971-977.
5 Infasurf® (calfactant) Intratrachael Supsension Prescribing Information. Rev. 06/11.