D-gluconic acid, compound with N,N''-bis(4-chlorophenyl)-3,12-diimino-2,4,11,13-tetraazatetradecanediamidine (2:1)

Phototransformation in air

Link to relevant study record(s)

Reference

Endpoint:

phototransformation in air

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

key study

Study period:

2005

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Qualifier:

no guideline followed

Principles of method if other than guideline:

Calculated with EPI-Suite (2005): Estimation of phototransformation in air of Chlorhexidine digluconate using AOPWIN v1.91

GLP compliance:

no

Estimation method (if used):

PHOTOCHEMICAL REACTION WITH OH RADICALS
- Concentration of OH radicals: 0.5•10E6 OH radicals per cm3 for a 24-hours-day

DT50:

< 1.3 h

Test condition:

Chlorhexidine

DT50:

9.1 h

Test condition:

D-Gluconic acid

Transformation products:

no

Rate constants:

Chlorhexidine digluconate, OH radicals: 3.8 · 10^-10cm³molecule^-1s^-1

Chlorhexidine gluconate, OH radicals: 3.4 · 10^-10cm³molecule^-1s^-1

Chlorhexidine,radicals: 3.0 · 10^-10cm³molecule^-1s^-1

D-Gluconic acid, OH radicals:4.2^.10^-11cm³molecule^-1s^-1 Half-lifes: τ_1/2(•OH) < 1.3 h (Chlorhexidine) τ_1/2(•OH) = 9.1 h (D-Gluconic acid)

Validity criteria fulfilled:

yes

Conclusions:

The results suggest that Chlorhexidine digluconate is very rapidly degraded in air by photo-oxidative processes. Significant amounts of Chlorhexidine digluconate are not likely to persist in air.

Key value for chemical safety assessment

Half-life in air:

1.3 h

Additional information

In the atmosphere, both Chlorhexidine base (τ_1/2(•OH) < 1.3 h) and Gluconic acid (τ_1/2(•OH) = 9.1 h) are rapidly degraded via reaction with OH radicals estimated using AopWin v.1.91. As the substance is expected to be not volatile from aqueous solution as well as that releases to air during production, formulation and use is negligible, this degradation mechanism is of minor importance.