Due to its low toxicity, biodegradability, and ability to release bioactive magnesium ions (Mg2+), magnesium hydroxide (Mg(OH)2) has recently broken through its traditional limitations as a simple antacid or laxative. It is showing immense potential in emerging fields such as bone tissue repair, drug delivery, and wound care. The following is an analysis of its specific new applications and future prospects:
1. Bone Tissue Repair: A Core Component of Multifunctional Composite Materials
- Optimizing 3D-Printed Bone Scaffolds: Recent research has further validated the core role of Mg(OH)2 in improving polylactic acid (PLA)-based bone scaffolds. PLA/ Mg(OH)2 composite scaffolds prepared via Fused Deposition Modeling (FDM) show that adding just 5wt% of Mg(OH)2 can increase tensile strength by 20.50% and compressive strength by 63.97%. Its alkaline degradation products neutralize the acidic substances produced during PLA degradation, preventing inflammatory responses. Furthermore, it continuously releases magnesium ions for over 28 days, promoting the adhesion and proliferation of bone marrow mesenchymal stem cells (BMSCs) while driving apatite deposition, thereby solving the problem of weak biomineralization in traditional polymer scaffolds.
- Preparation of Magnesium-Doped Calcium-Phosphorus Repair Materials: Mg(OH)2 serves as a magnesium source in the synthesis of novel bone repair materials. For instance, using Mg(OH)2, calcium hydroxide, and phosphoric acid as raw materials, a magnesium-doped biphasic calcium-phosphorus inorganic material can be synthesized via the wet chemical method. This material combines the high osteogenic activity of hydroxyapatite (HA) with the high biodegradability of β-tricalcium phosphate (β-TCP). As it degrades, it slowly releases calcium and magnesium ions, inducing the attachment and proliferation of osteoblasts. This preparation process is simple and produces no impurities, making it highly suitable for clinical bone defect filling.
- Aiding the Repair of Difficult Conditions like Osteonecrosis: Layered double hydroxide (LDH) nanosheets containing Mg(OH)2 have demonstrated significant osteogenic effects. For example, ytterbium-containing Mg-Al LDH nanosheets achieved a loading capacity of 197% and an encapsulation efficiency of 98.6% for Alendronate. In animal experiments, the bone regeneration volume in rabbit femoral heads treated with this material was 1.41 times that of the autologous bone graft group, and bone density increased 1.52 times eight weeks after surgery. This provides a brand-new therapeutic approach for refractory diseases such as osteonecrosis of the femoral head combined with osteoporosis.
2. Drug Formulations: Breakthroughs as Green Excipients and Intelligent Carriers
- Upgrading Pharmaceutical Excipient Performance: As an eco-friendly pH regulator, Mg(OH)2 is gradually replacing synthetic excipients like phosphates in the preparation of tablets and suspensions. It regulates the acidity of formulations mildly and stably, decomposing into magnesium ions and water in the body without leaving residual pollution, aligning with green pharmacy principles. Additionally, ultra-fine Mg(OH)2 particles can uniformly cover the gastric mucosa, quickly neutralizing gastric acid while forming a protective film, offering superior protection compared to traditional antacids.
- Serving as Sustained-Release Drug Carriers: Nano-magnesium hydroxide, with its large specific surface area and excellent adsorption properties, has become an ideal carrier for antibiotics and anti-cancer drugs. It can adsorb drugs onto its surface or within its pores; once inside the body, the drug is released gradually as the Mg(OH)2 degrades. This not only extends the duration of drug action and improves bioavailability but also reduces side effects caused by fluctuations in drug concentration, showing significant advantages in long-term medication scenarios.
3. Wound and Mucosal Care: A Novel Component for Antibacterial Materials
Nano-magnesium hydroxide has a significant inhibitory effect on common pathogens such as Staphylococcus aureus and Escherichia coli. This characteristic has made it a rising star in wound care. When added to medical gauze or hydrogel dressings, it destroys the survival conditions for bacteria through an alkaline environment, while the released magnesium ions reduce inflammation and create a favorable environment for wound healing. Furthermore, its mild alkalinity can be used to alleviate inflammation in the oral and vaginal mucosa without irritating normal tissue, offering potential for the development of new mucosal care preparations.
4. Joint Repair: Synergistic Scaffolds for Cartilage and Subchondral Bone Regeneration
Mg(OH)2 derived Mg-Al LDH nanosheets, after surface modification, can be used to coat β-tricalcium phosphate scaffolds. This composite scaffold not only possesses the compressive strength required for joints but also releases bioactive components like magnesium ions to simultaneously promote the osteogenic differentiation of BMSCs and the proliferation of chondrocytes. Experiments show that this scaffold promotes calcium salt deposition and alkaline phosphatase (ALP) production while enhancing chondrocyte metabolism and controlling the expression of genes related to catabolism. This provides a feasible solution for the integrated repair of joint cartilage and subchondral bone, potentially solving the clinical challenge of non-synchronized regeneration.
Future Outlook
The prospects for magnesium hydroxide in the biomedical field are exceptionally broad. On one hand, its raw materials come from natural resources like brucite and salt lake brine, making it widely available and environmentally friendly to produce, which aligns with the green development trends in medicine. On the other hand, as surface modification and composite preparation technologies mature, its biocompatibility continues to improve, and its applications may expand toward periodontal repair and tissue engineering scaffold coatings.
However, several challenges remain, such as controlling the cost of mass-producing nano-grade β and conducting comprehensive long-term in vivo biosafety assessments. Once these technical bottlenecks are overcome, magnesium hydroxide will achieve large-scale clinical translation in the biomedical field.