I was doing a phototoxicity experiment on Balb3t3 cells using chlorpromazine hydrochloride as positive control and sodium lauryl sulfate as negative control. I followed the oecd 432 guideline procedure and then the results were as follows:

Chlorpromzine Hydrochloride

1. ic50 with radiation: 5.3ug/ml

2. ic50 without radiation: 25.8ug/ml

3. PIF: 5.9

4. MPE: 0.493

Sodium lauryl sulfate

1. ic50 with radiation: 5.4ug/ml

2. ic50 without radiation: 7.1ug/ml

3. PIF: 1.33

4. MPE: 0.139

as per guideline reported

Chlorpromzine Hydrochloride

1. ic50 with radiation: 0.1 - 2ug/ml

2. ic50 without radiation: 7 - 90ug/ml

3. PIF: >14.4

4. MPE: 0.33 - 0.63

Sodium lauryl sulfate

1. PIF: 1.0 - 1.9

2. MPE: 0.00 - 0.05

the guideline also mentions the following conditions for any compound:

for no phototoxicity PIF 0.15

can anyone help why I may not be getting the results as suggested.