Peculiar prescription with the mention: PLO ointment.

PLO ointment, usually called PLO Gel, is a widely used excipient in the US mainly to obtain a good transdermal absorption. The composition is as follows:

soy lecithin 10g Isopropyl palmitate 10g Sorbic acid 300mg Pluronic Gel 20% up to 100g

The preparation is done in two steps

1. preparation of Pluronic or Poloxamer gel Pluronic or Lutrol are brand names for Poloxamer, which is itself a copolymer of ethylene and propylene oxide. Depending on the amount of ethylene oxide groups (hydrophilic) and the Propylene oxide groups (lipophilic), the copolymer has a hydrophilic or lipophilic or intermediate character.

   Usually Poloxamer 407 is used. This corresponds to Lutrol F 127 (BASF). See this link

   Composition:

   Pluronic or Lutrol F 127 20g Sorbic acid 100mg Purified water up to 100g

   Preparation mode: In a tarred salmon pot, mix the poloxamer with sorbic acid and then with ice cold water. Once all the grains have absorbed water (this can take 12 hours), place the gel overnight in the refrigerator to promote dissolving and gel formation.

    

2. Preparation of the PLO gel disperse lecithin and sorbic acid in isopropyl palmitate in a tarred beaker and let it rest overnight. A liquid with the consistency of syrup is formed. Add Poloxamer 20% gel to 100g.

Note: Both gels have a shelf life of six months.