How can I make a solution with Methoxypsoralen for bathing hands and feet for PUVA?

Regarding the concentration this is shown in the following article:  

PUVA therapy for psoriasis: Comparison of oral and bath-water delivery of 8-Methoxypsoralen

From The Division of Dermatology, University of California at Los Angeles Medical School.

https:/Doi.org/10.1016/s0190-9622 (86) 70089-3 Get Rights and Content A Direct clinical comparison has been made of the efficacy of oral 8-Methoxypsoralen with bath-water delivery of 8-Methoxypsoralen during Psoralen Ultraviolet A (PUVA) phototherapy for A Group of forty patients with Stable plaque-type psoriasis vulgaris. The 8-Methoxypsoralen concentration was 3.7 mg/liter in the bath water. The efficacy of these treatments was assessed by their ability to improve or clear the psoriasis. The skin of eight of the twenty patients with oral psoralen cleared, and another eight showed good improvement. Of the twenty patients who received 8-methoxypsoralen in bathwater, eight patients had clearing of the skin, whereas nine patients had good improvement during the initial 8-week treatment period. Administration of 8-Methoxypsoralen in bath water required much lower ultraviolet A irradiance to achieve maximum improvement. There were no systemic side effects in the patients treated by bath-water delivery; However, some patients did develop phototoxic erythema. Minimal phototoxic doses were also studied in patients and in volunteers using both routes of psoralen delivery. The minimal phototoxic dose threshold after psoralen bath delivery It been about five treatments from 5.3 ± 0.6 joules/cm ² to 2.8 ± 0.3 joules/cm ² , suggesting an accumulation of psoralen in the skin with this method of drug Delivery. Bath-Water delivery of 8-Methoxypsoralen was therefore found to be as effective as oral administration of 8-methoxypsoralen and yet required narrower amounts of ultraviolet A radiation and yielded fewer side effects. It would thus seem to be confirmed as a useful alternative means of 8-methoxypsoralen administration in PUVA therapy.

The hands should be bathed in a bath of 1.5 litres. The prescription stated that 0.9 ml of the prepared liquid should be added to the Be. We can finish this better at 1 ml. The final concentration should be 4 mg/1 litre (or 6 mg/1.5 L)

a tablet of Mopsoralen contains 10 mg per tablet. After fine rubbing the tablet, 8-MOP can be extracted with a mixture   acetone-ethanol 1:9. Eighteen tablets are crushed and the powder is topped in a beaker with 20 ml of a mixture of acetone-ethanol 1:9.   A magnetic stirrer is placed In the beaker before it is covered with a watch glass. The beaker is placed on a magnetic plate   at a temperature of approximately 35 ° C for 20   minutes. After that, the contents of the beaker are filtered in a dimensionciinder. Beaker and residue is washed with 10 ml of the mixture of acetone-methanol. The same liquid mixture is placed on a volume of 30 ml.   this way you theoretically get 6 mg per ml. The patient brings 1 ml of this solution in 1.5 liters of water. This corresponds to 4 mg/litre, or after possible losses we reach 3.6 to 3.7 mg/liter.