weave-lock

This drug was designed to limit the effects of magical disease and curses it does this by dampening the weave around the blood of the person who ingested it. its origin is from flail snail shell powder enchanted with magic resistance and encased in a small pill. a pill is one dose a injection is between 2 and 5 doses. (1d4+1)
one dose causes you too lose a spell slot for a day once a spell caster is out of spell slots ten additional doses causes the permanent spell slot loss of there lowest spell slot once a creature has lost all its spell slots additional doses gives them the ability anti magic body for one hour and also the poisoned condition. if you are not a spell caster you take 1d4 magic damage when you receive a dosage.
Antimagic body. The creature has advantage on saving throws against spells, and any creature making a spell attack against the creature has disadvantage on the attack roll. If the creature succeeds on its saving throw against a spell or a spell attack misses it, an additional effect might occur, as determined by rolling a d6: 1-2: If the spell affects an area or has multiple targets, it fails and has no effect. If the spell targets only the creature, it has no effect on the creature and is reflected back at the caster, using the spell slot level, spell save DC, attack bonus, and spellcasting ability of the caster.
3-4: No additional effect.
5-6: The creature's body converts some of the spell's energy into a burst of destructive force. Each creature within 30 feet of the creature must make a DC 15 Constitution saving throw, taking 1d6 force damage per level of the spell on a failed save, or half as much damage on a successful one.
note these effects can be removed by greater restoration.

Utility

can be used to limit magical abilities of creatures or to calm symptoms of magical disseas. higher doses can limit someones spell casting ability drastically each pill causes you to loose one random spell slot for the day. overdose can cause you to become completely magically sterile losing all magical ability.

Manufacturing

any pharmacist or medical professional can make it given the ingredients

Inventor(s)

Gnomes who hated magical crimes decided to use science to counter act it

Access & Availability

its rare and expensive a case can be worth between 300gp or 1000gp depending on circumstance a case holds 100 days worth(aka 100 doses) of treatment which can cure about 33 people (3 doses medicine cures the disease)

Complexity

it's a rather simple drug but hard to get ingredient such as flail snail shell

Discovery

discovered by Gnomenighm engineers who wanted to limit magic usage of people in prison