lanthanum carbonate to control phosphate

[Seneca]

lanthanum carbonate is used as a phosphate binder in humans with renal failure. In seawater lanthanum carbonate is very insoluble, but not totally. Might lanthanum carbonate work as a solid phosphate binder like gfo or aluminum oxide? It should work slowly.

Such was my hypothesis.

I took a sample of saltwater with a phosphate level of 3.5 ppm (per Hanna ul phosphorus checker, diluted 10x with rodi), and put a few grams of very fine lanthanum carbonate in a 1 liter container with it.

After a week it was 2.5 ppm, after 2 months, it was zero.

So it does appear to work, albeit very slowly and I have no idea how efficient it would be. Lanthanum ions bind phosphate ions preferentially to carbonate ions.

I'm going to put a few hundred grams just under a layer of sand in a bucket in my sump and see if it helps control my phosphate levels. If solid lanthanum carbonate can be slowly converted to lanthanum phosphate it should be much safer for fish (I killed two tangs with lanthanum chloride when dosing substantially upstream of a 5 um filter sock over a very long period of time, and hand 5 other tangs breathing very heavy for 12 hours after it was stopped; naso, and acanthurus genus tangs didn't seem to care).

GFO is too expensive for my set-up.

 

[Randy Holmes-Farley]

lanthanum carbonate is used as a phosphate binder in humans with renal failure. In seawater lanthanum carbonate is very insoluble, but not totally. Might lanthanum carbonate work as a solid phosphate binder like gfo or aluminum oxide? It should work slowly.

Such was my hypothesis.

I took a sample of saltwater with a phosphate level of 3.5 ppm (per Hanna ul phosphorus checker, diluted 10x with rodi), and put a few grams of very fine lanthanum carbonate in a 1 liter container with it.

After a week it was 2.5 ppm, after 2 months, it was zero.

So it does appear to work, albeit very slowly and I have no idea how efficient it would be.

I'm going to put a few hundred grams just under a layer of sand in a bucket in my sump and see if it helps control my phosphate levels. If solid lanthanum carbonate can be slowly converted to lanthanum phosphate it should be much safer for fish (I killed two tangs with lanthanum chloride when dosing substantially upstream of a 5 um filter sock over a very long period of time, and hand 5 other tangs breathing very heavy for 12 hours after it was stopped).

GFO is too expensive for my set-up.

Lathanum carbonate is cheaper than GFO?

I'm super familiar with that application of lanthanum since it competed with one of my inventions: a polymer to bind phosphate in renal patients.

Lanthanum carbonate works in people because it dissolves in the acidic environment of the stomach, and then lanthanum phosphate can precipitate in the stomach and small intestine. It is not because phosphate binds to the surface of the solid particles. It will, but there's low surface area compared to intentionally high surface area materials like GFO.

My concern in seawater is that lanthanum carbonate won't dissolve (or not much, anyway). Just like calcium carbonate not dissolving.

If it does slowly dissolve to work, I'm not sure why that is better than using lanthanum chloride liquid solutions.

 

[Seneca]

Lathanum carbonate is cheaper than GFO?

It certainly is if you make it out of lanthanum chloride, which I did. The key question is the one you bring up.

My concern in seawater is that lanthanum carbonate won't dissolve (or not much, anyway). Just like calcium carbonate not dissolving.

It doesn't, in principle, need to dissolve very much. It needs a tiny percentage of it to dissolve at a time to become locally available to bind phosphate ions instead.

If it does slowly dissolve to work, I'm not sure why that is better than using lanthanum chloride liquid solutions.

The principle is that it won't travel before finding another phosphate (or carbonate) ion. Lanthanum carbonate and calcium carbonate for that matter are at equilibrium in seawater. The equilibrium radically favors the insoluble form for both. This could be a feature not a bug if lanthanum carbonate can slowly be converted to lanthanum phosphate over a long period of time.

The real question is whether this only happens at the very surface of the particles, or if it happens deeper in the particles. Regardless small particle size would be important.

I plan to repeat my 1 liter experiment with a stoichiometrically equivalent quantity of phosphate and lanthanum carbonate from sigma in saltwater.

 

[Randy Holmes-Farley]

OK, let's see what happens.

 

[DrZoidburg]

Lathanum carbonate is cheaper than GFO?

I'm super familiar with that application of lanthanum since it competed with one of my inventions: a polymer to bind phosphate in renal patients.

Lanthanum carbonate works in people because it dissolves in the acidic environment of the stomach, and then lanthanum phosphate can precipitate in the stomach and small intestine. It is not because phosphate binds to the surface of the solid particles. It will, but there's low surface area compared to intentionally high surface area materials like GFO.

My concern in seawater is that lanthanum carbonate won't dissolve (or not much, anyway). Just like calcium carbonate not dissolving.

If it does slowly dissolve to work, I'm not sure why that is better than using lanthanum chloride liquid solutions.

How similar to sevelamer, colestila, bixalomer, maybe chitosan type, or none of them? I forget if it was ever mentioned. Just makes me wonder.

 

[Dennis Cartier]

Interesting. You can buy Lanthanum Carbonate fairly cheaply in China. Even medical grade purity.

It binds best at low PH, which can occur in sand beds, so your test of placing it under a sand bed is reasonable.

Another possible test is to use a dosing pump to slowly exchange tank water through a vessel containing lanthanum carbonate. With a slow enough dosing rate, the water inside of the vessel would become anaerobic and eventually anoxic and as a result have a lower PH (I believe). How anaerobic it becomes could be monitored and controller using am ORP probe, and the PH could be monitored and controlled using a PH probe. Keeping the PH low enough without generating hydrogen sulfide would be the objective.

I look forward to the results of your test.

Dennis

 

[DrZoidburg]

Seems like playing with matches and gasoline.

 

[Randy Holmes-Farley]

How similar to sevelamer, colestila, bixalomer, maybe chitosan type, or none of them? I forget if it was ever mentioned. Just makes me wonder.

What do you mean by similar?

Sevelamer (my drug) and other organic polymers bind phosphate in the small intestine by ion exchange to the positive charges on the organic polymer. The polymer is then excreted with the phosphate attached.

Lanthanum (as well as calcium and aluminum drugs for this purpose) work by precipitation of lanthanum phosphate (or calcium or aluminum phosphate). That can begin in the stomach and also proceeds in the small intestine. The precipitated phosphate solids are then excreted.

 

[DrZoidburg]

What do you mean by similar?

Sevelamer (my drug) and other organic polymers bind phosphate in the small intestine by ion exchange to the positive charges on the organic polymer. The polymer is then excreted with the phosphate attached.

Lanthanum (as well as calcium and aluminum drugs for this purpose) work by precipitation of lanthanum phosphate (or calcium or aluminum phosphate). That can begin in the stomach and also proceeds in the small intestine. The precipitated phosphate solids are then excreted.

I ask similar because I figured it was not them. The patent information shows someone elses name.

 

[Randy Holmes-Farley]

Interesting. You can buy Lanthanum Carbonate fairly cheaply in China. Even medical grade purity.

It binds best at low PH, which can occur in sand beds, so your test of placing it under a sand bed is reasonable.

Another possible test is to use a dosing pump to slowly exchange tank water through a vessel containing lanthanum carbonate. With a slow enough dosing rate, the water inside of the vessel would become anaerobic and eventually anoxic and as a result have a lower PH (I believe). How anaerobic it becomes could be monitored and controller using am ORP probe, and the PH could be monitored and controlled using a PH probe. Keeping the PH low enough without generating hydrogen sulfide would be the objective.

I look forward to the results of your test.

Dennis

The undissolved particles of lanthanum carbonate, and fully dissolved lanthanum ions will not bind phosphate best at low pH. They will bind it better at higher pH where a larger fraction of the phosphate is present as PO4---.

Sufficiently low pH will allow dissolution of lanthanum carbonate, and then the lanthanum can precipitate as lanthanum phosphate, but IMO, that is unlikely to happen in a sand bed since the pH is not low enough (calcium carbonate sand will dissolve first).

 

[Randy Holmes-Farley]

I ask similar because I figured it was not them. The patent information shows someone elses name.

Not sure what you are asking about. None of the names you mentioned are a lanthanum product. They are all organic polymers (I assume you meant colestid instead of colestia)

Fosrenol is a chewable lanthanum carbonate tablet.

 

[DrZoidburg]

Not sure what you are asking about. None of the names you mentioned are a lanthanum product. They are all organic polymers (I assume you meant colestid instead of colestia)

Fosrenol is a chewable lanthanum carbonate tablet.

Generally just curious about the chemistry of them, so I look into them. Call me weird but I like looking at molecule drawings. You say yours was a polymer sevelamer. These other names come up in patent. I wasn't able to pm.

 

[Randy Holmes-Farley]

Generally just curious about the chemistry of them, so I look into them. Call me weird but I like looking at molecule drawings. You say yours was a polymer sevelamer. These other names come up in patent. I wasn't able to pm.

Sevelamer was covered by a number of patents (all composition patents are now expired). I am a co-inventor on all of the composition of matter patents for sevelamer (not on some later formulation patents). I go by my middle name. Stephen is my first name.

Here's the first of the sevelamer patents:

Patent Public Search | USPTO

patft.uspto.gov

 

[Dennis Cartier]

The undissolved particles of lanthanum carbonate, and fully dissolved lanthanum ions will not bind phosphate best at low pH. They will bind it better at higher pH where a larger fraction of the phosphate is present as PO4---.

Sufficiently low pH will allow dissolution of lanthanum carbonate, and then the lanthanum can precipitate as lanthanum phosphate, but IMO, that is unlikely to happen in a sand bed since the pH is not low enough (calcium carbonate sand will dissolve first).

Ok, so my idea is a non-starter. I need to run more of my schemes by you BEFORE I go to the trouble and expense of doing the tests myself, lol!

I still look forward to seeing what the OP comes up with in his testing.

Dennis

 

[fermentedhiker]

Would a possible application for this be mixed in with the media in a calcium reactor to cancel out the phosphate released by the coral skeletons as they dissolve?

 

[DrZoidburg]

I see now with that title. Why let it expire? or sold?

 

[Randy Holmes-Farley]

Would a possible application for this be mixed in with the media in a calcium reactor to cancel out the phosphate released by the coral skeletons as they dissolve?

It might, but if that is a problem, I'd suggest a material that binds phosphate in the solid form, such as alumina (Seachem phosguard or Kent phosphate sponge).

But I think that source is typically small compared to foods, so it may not impact the overall balance much.

 

[Randy Holmes-Farley]

I see now with that title. Why let it expire? or sold?

Patents must expire after a certain number of years. In the US, it is now 20 years after the first application.

 

[DrZoidburg]

Also see after 2009 it got wonky with legal disputes.

 

[Randy Holmes-Farley]

Also see after 2009 it got wonky with legal disputes.

Yes, that was fun. My company sued some generic companies that tried to come to market before all of the patents expired. If I remember correctly, they accepted the validity of that patent I posted, but were challenging a later one that had a later expiration date.

I was in Baltimore at the Federal courthouse in preparation for the trial, and was going to testify the next day, but the companies settled the night before I was to testify about various aspects relating to sevelamer . Disappointing for me, but I guess everyone else was happy.

Then later the generic companies discovered they could not easily come to market even without patents blocking them. The polymer is not easy to make at the cost those companies required to compete. It was a surprisingly long time (years, I think) before they finally came to market in the US with any material not made by Genzyme or its contractors.

At its peak, Genzyme sold more than a billion dollars worth each year.