How do I best prepare a deptropine citrate syrup?

composition for 100 ml syrup according to the Formularium Dutch pharmacists:

Deptropinecitraat 10.5 mg
monosodium hydrogen phosphate 2aq 150 mg
disodium hydrogen phosphate 12 aq 1.45 g
sorbitol 18 g
Nipagine 130 mg
Propylene glycol 100 mg
Banana Essence 100 mg
water to 100 ml (106.5 g)

Preparation:

1. Tarreer A beaker of 125 à 150 ml and note the tare weight
2. dissolve 18 g of sorbitol in 50 ml Freshly boiled water
3. add to the Sorbitol solution 100 mg propylene glycol and 130 mg nipagine
4. dissolve the nipagine on possibly under heating
5. dissolve monohydrogen, disodium hydrogen phosphate and deptropinecitraat in 20 ml of water
6. mix the Deptropinecitraat solution with the cooled Nipagine-sorbitol solution
7. Rinse the Recipi ë nt of the Deptropinecitraate solution with 20 ml of water
8. add the banana essence
9. apply weight with water and mix

Control: pH = +/-7.3

Note: This beverage should be stored with KT in connection with the probability of crystallization of methylparahydroxybenzoeic acid. In these circumstances, the shelf life is 1 year.