Gallium-Doped Phosphocalcic Compounds for Local Bone Delivery
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Solution Overview
Problem
Current systemic administration of gallium results in low absorption onto bone material and high potential for side effects, necessitating an alternative administration route for treating bone diseases like osteoporosis, Paget's disease, or osteolytic tumors, with the need for precise control over gallium release.
Innovation Solution
Development of gallium-doped phosphocalcic compounds, specifically calcium phosphate compounds with a Ca/P molar ratio between 1.28 and 1.5, which can be incorporated into self-setting calcium phosphate cements for local release of gallium upon degradation by bone cells, allowing for controlled and prolonged gallium delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If gallium is administered systemically, then gallium can reach bone tissue, but absorption onto bone material is low and side effects are high
Solution Approach 1:
The patent applies local quality by developing gallium-doped calcium phosphate compounds that release gallium locally at the bone site. The compounds are designed to degrade in situ and release gallium specifically where needed, rather than distributing gallium systemically throughout the body. This localized delivery increases gallium concentration at the target bone tissue while minimizing exposure to other organs and reducing side effects.
Solution Approach 2:
The patent uses calcium phosphate compounds as intermediary carriers to deliver gallium to bone tissue. These compounds serve as a mediator that transports gallium from the administration site to the bone, where the calcium phosphate degrades and releases gallium. This intermediary approach allows controlled delivery and improves bone uptake efficiency while reducing the need for high systemic doses.
2Quantity of substance
If gallium is administered systemically, then gallium can treat bone diseases, but the dosage is difficult to control precisely
Solution Approach 1:
The patent applies preliminary action by pre-loading the calcium phosphate compounds with a specific amount of gallium during compound synthesis. The gallium is incorporated into the crystal structure at known concentrations, allowing precise control of the total gallium content before administration. This pre-determined loading ensures that a known quantity of gallium is delivered to the bone site, improving dosage precision.
Solution Approach 2:
The patent utilizes the dynamic degradation of calcium phosphate compounds to control gallium release over time. The compounds degrade progressively in the physiological environment, releasing gallium in a controlled temporal manner. This dynamic release profile allows precise control of the dosage rate and duration, matching therapeutic needs while avoiding overdose.
3Speed
If highly water soluble calcium phosphate compounds like brushite are used, then gallium release is rapid, but the activity span is short and risk of overdosage is high
Solution Approach 1:
The patent applies parameter changes by systematically varying the calcium phosphate compound composition and crystallinity to control water solubility and degradation rate. By adjusting parameters such as Ca/P ratio, presence of carbonate, and degree of crystallinity, the invention creates compounds with intermediate solubility that release gallium at a moderate, sustained rate. This optimizes both the speed and duration of gallium release, avoiding the extremes of too rapid or too slow release.
Solution Approach 2:
The patent uses composite materials by combining gallium-doped calcium phosphate with other biocompatible materials or using multi-phase calcium phosphate composites. These composite structures can modulate the degradation rate and gallium release profile, providing sustained release over extended periods while maintaining biocompatibility and osteoconductivity.
4Duration of action of moving object
If sparingly water soluble calcium phosphate compounds like hydroxyapatite are used, then gallium release is slow and prolonged, but the release may be insufficient for therapeutic effect
Solution Approach 1:
The patent applies parameter changes by modifying the calcium phosphate compound properties (such as creating less crystalline phases, adjusting Ca/P ratio, adding carbonate) to increase water solubility and degradation rate compared to standard hydroxyapatite. These parameter adjustments accelerate gallium release kinetics and increase the total quantity released, while still maintaining prolonged release duration through controlled degradation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The gallium-doped phosphocalcic compounds enable a slow and sustained release of gallium in situ, reducing the risk of overdosage and improving therapeutic efficacy while minimizing side effects, making them suitable for treating bone diseases.
Implementation Method 1
Gallium is known to adsorb in vitro to synthetic hydroxyapatite and as a result crystallization and probably dissolution of hydroxyapatite is decreased
Implementation Method 2
which can be incorporated into self-setting calcium phosphate cements for local release of gallium upon degradation by bone cells
Data Source
AI summary
The present invention relates to a gallium-doped phosphocalcic compound of formula (I):Ca(10.5-1.5x)Gax(PO4)7 (I)wherein 0<x<1 and the salts, hydrates and mixtures thereof.The invention further relates to a solid state process and a process in solution for the manufacture of such compounds and the use thereof for the preparation of a biomaterial, in particular a self-setting calcium-phosphate cement (CPC).