The part A is likely the developing agent with some sulfite/other oxygen scavengers. The B will be the balance of the sulfite and the alkali.
You may want to try to dissolve the part A in warmed polyethelene glycol (plumbing system anti freeze. The trick is to find the stuff without the red dye around here.) I have done this with makes 10L type kits if other film developer, to give me a part A of about 1.5L. The PEG keeps any oxygen that gets dissolved when dissolving in water from being oxidized by the developing agent.
Part B goes into water, since there is no developer to oxidize. I find you need to approach 4L to keep the B from crystalizing out when the hot water aiding dissoving it cools.
Then when you want to develop you syringe draw a proportionate amount of A out. For me, to make up 300mL of developer, full strength took 45ml of A, and 120 mL of B, and the balance of warmed distilled water to make up the full strength developer at working strength to process one 35mm film in a Paterson or stainelss steel tank.
This type of mix for me worked well for over 4 years before I used the last of it up.