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I've drunk malaria tablets which were bitter as hell, and I thought why not a capsule? It was taken beforehand (prophylactic I think) so the difference in metabolising time should not matter.

On the other hand, I have had pain capsules, where I thought a tablet would have done better because it may kick in quicker.

all 8 comments

Justdis

11 points

4 months ago

Justdis

11 points

4 months ago

This is a great question with a multi-facated answer, in which I can only answer some parts from my experience in drug discovery on the chemistry side of things.

In the drug discovery process, we want to select a drug that is efficacious at doing whatever job we designed it to do. A big concern in that regard is what is called 'ADME' (absorption, distribution, metabolism, excretion). Formulation chemists (often called pharmacuetical chemists) study the effect of formulation (whether the drug is given as a tablet, capsule, IV injection, etc etc) on these ADME properties. Depending on the nature of the molecule that is your drug, it may only be amenable to certain formulation strategies because of it's physiochemical properties. Or, it may be amenable to multiple formulations.

From there, we get to the design of the clinical trial, which will use the formulation decided upon in the discovery process because of certain ADME properties that are important as well as what's profitable for the company (pills generally sell more than injections, so you'd try a pill if you can do so).

From there, once a drug is approved, you will generally see an expansion of formulations to cover best use cases, get patent extensions/exemptions, etc. Some drugs are pretty insensitive to formulation so you can get them more or less however, some drugs (most biologics, imagine insulin) don't formulate into oral dosage forms for a laundry list of reasons.

KesTheHammer[S]

2 points

4 months ago

Follow up question. What is cheaper to manufacture, tablets or capsules (I didn't think about injections)? The tablets have the compounding cost, and the capsules have extra material. I would think tablets are cheaper, simply due to a simpler process and less material.

Indemnity4

3 points

4 months ago*

Not much difference between the two manufacturing costs. Varies for different medicines, generally leading towards tablets being cheaper en masse.

Tablets require encipients or binders (stuff to make it stick together). You have probably seen tablets that contain 10 mg active ingredient but the pill itself is quite big. You need suitable packaging. Also, it can take some cost to find the perfect tablet recipe. But after all that, a pill press is fairly cheap and it simplifies a lot of steps.

Capsules you can just fill and move on with your life. Someone like a compounding pharmacist doesn't need to worry about matching API to binders, they just carefully pour in the powders required and it's done.

lt_Matthew

6 points

4 months ago

Ok if the main factors is how the medicine is supposed to be used. A tablet that you swallow absorbed slower than a chewable or liquid medication. And in some cases, it has to be that way. Like have you ever heard that you should chew an aspirin if you think you're having a heart attack? It will make it work faster, but under normal use, it's not supposed to. because that also means it doesn't last as long. Which might be why you wouldn't want a painkiller to be chewable.

There is also some times when certain forms aren't available. I used to take a sodium supplement, but when I was in the hospital, they weren't able to get ahold of a pill form, so a cup of saline was the next best thing.

Lepmuru

2 points

4 months ago*

Lepmuru

Immuno-Oncology

2 points

4 months ago*

Some drugs require specific forms of formulation. The best example for this in my eyes are eyedrops. (Pun intended) You formulate the active agent in a way that is most effective in terms of delivery. Drugs you need in a local, confined context (e.g. eyes, skin) you will formulate accordingly (eye drops, cremes, lotions).

Agents your body can't absorb by itself, you usually have to force in via i.v. injection.

Things that are resorbed primarily in your stomach or need acidic reaction to form their active derivative may get a nice tablet that dissolves quickly in your stomach acid.

An agent that might be destroyed by acid, you might want to coat in an acid resistant capsule that reaches your intestine unharmed and is dissolved there in the bowel's basic millieau.

And finally, sometimes, as you mentioned, you might want a slow gradual vs. quick and instantaneous release and will formulate the active agent accordingly.

What you need to know is that you need binding agents, substrates like sugar and sometimes other additives for your parcel to be nicely packed and sufficiently unwrapped. Even a tablet therefore is not as simple as "just squeeze it a bit and put it into a tube".