What oral drug delivery process is used for iron supplements that are only released in the liver?

From the Guidelines

Liposomal iron delivery is the oral drug delivery process used for iron supplements that are specifically released in the liver. This method is highlighted in recent studies as a potential advantage over traditional oral iron preparations due to its unique mechanism of action, which avoids direct contact of iron with the intestinal mucosa and bypasses the intestinal hepcidin-ferroportin block via a different uptake mechanism into intestinal M cells 1. The use of liposomal iron has been shown to increase hemoglobin levels in patients with non-dialysis-dependent chronic kidney disease (NDCKD), although larger confirmatory trials are needed to fully establish its benefits and risks compared to established oral iron compounds or intravenous iron preparations 1.

Key points about liposomal iron delivery include:

• It encapsulates iron compounds within phospholipid bilayers, protecting the iron from degradation in the stomach and intestines.
• The liposomes are transported via the lymphatic system and eventually to the liver, where they are metabolized and the iron is released.
• This targeted approach minimizes common gastrointestinal side effects associated with traditional iron supplements.
• The liver-specific release is beneficial because the liver is a primary storage site for iron in the body and plays a crucial role in iron metabolism through the production of hepcidin.

The potential benefits of liposomal iron delivery, as suggested by preliminary evidence, include improved efficacy and tolerability compared to previously available oral iron preparations 1. However, more research is needed to fully understand the advantages and disadvantages of this oral drug delivery process.

In terms of specific products, liposomal iron bisglycinate or liposomal ferric pyrophosphate are examples of supplements using this technology, but the most recent and highest quality study 1 does not provide detailed information on these specific products. Overall, the use of liposomal iron delivery for iron supplements that are specifically released in the liver represents a promising area of research with potential implications for improving patient outcomes, particularly in terms of reducing morbidity, mortality, and enhancing quality of life.

From the Research

Oral Drug Delivery Process for Iron Supplements

There are no research papers that specifically discuss an oral drug delivery process for iron supplements that are only released in the liver. However, the available studies provide information on oral iron delivery systems and their mechanisms.

Mechanisms of Oral Iron Delivery

• Iron can be administered orally as iron(II) (ferrous) salts or iron(III) (ferric) complexes 2.
• Iron-bearing proteins are easily degraded by digestive enzymes and absorbed through receptor-mediated endocytosis 3.
• Protein aggregates are slowly degraded in the stomach, which delays iron release and serves as a potential iron supplement 3.
• Amino acids, peptides, and polysaccharides can bind iron through iron binding sites, but the formed compounds are prone to dissociation in the stomach 3.
• Complexes formed by polysaccharides and proteins, and microcapsules formed by polysaccharides can delay the release of iron in the gastric environment and prolong iron release in the intestinal environment 3.

Controlled Release of Iron

• Controlled drug delivery systems have the advantage of maintaining therapeutically optimum drug concentrations in the plasma through zero-order release without significant fluctuations 4.
• Oral controlled-release drug delivery systems can minimize the daily dose of a drug required to maintain the required therapeutic effect, while minimizing unwanted pharmacological effects 4.
• Liposomes are unstable during gastric digestion and iron is released in large quantities 3.

Bioavailability of Iron

• Ferrous iron is absorbed 4 to 10 times better than ferric iron from therapeutic oral 50--250 mg iron doses 5.
• Ferrous sulfate iron is 3 to 4 times better available than the iron from ferric ammonium citrate or sulfate 5.
• The bioavailability of ferric iron is poor, and high-molecular weight ferric hydroxide-carbohydrate complexes are practically without effect on hemoglobin regeneration even at a daily 300 mg Fe dose 5.