Preparation of porous particles with multiple markers

A method for preparing a porous particle, comprising the steps of:

• A) providing:
• a first water-in-oil emulsion comprising a first pore stabilizing hydrocolloid and a first marker material in a first aqueous phase that is dispersed in a first oil phase containing a first polymer and a first organic solvent, and
• a second water-in-oil emulsion comprising a second pore stabilizing hydrocolloid in a second aqueous phase that is dispersed in a second oil phase containing a second polymer and a second organic solvent,
• B) combining the first and second water-in-oil emulsions to form a third water-in-oil emulsion containing a mixture of the first and second oil phases and distinct droplets of the first and second aqueous phases,
• C) dispersing the third water-in-oil emulsion in a third aqueous phase containing a surface stabilizing agent to form a water-in-oil-in-water emulsion containing droplets of the third water-in-oil emulsion, which third water-in-oil emulsion droplets contain the distinct droplets of the first and second aqueous phases, and
• D) removing the first and second organic solvents of the oil phases from the water-in-oil-in-water emulsion to form a solidified precursor porous particle comprising the first and second polymers that provide a continuous solid phase comprising the first and second polymers and including an external particle surface, and first and second discrete pores that are isolated from each other and dispersed within the continuous solid phase, and isolating the precursor porous particle to provide porous particles,
• the porous particles further comprising the first marker material within the first discrete pores.

A method for preparing a porous particle, comprising the steps of:

• A) providing:
• a first water-in-oil emulsion comprising a first pore stabilizing hydrocolloid and a first marker material in a first aqueous phase that is dispersed in a first oil phase containing:
• a first polymer or
• at least one first ethylenically unsaturated polymerizable monomer and a first polymerization initiator, and
• optionally, a first organic solvent, and
• a second water-in-oil emulsion comprising a second pore stabilizing hydrocolloid and a second marker material in a second aqueous phase that is dispersed in a second oil phase containing:
• a second polymer or
• at least one second ethylenically unsaturated polymerizable monomer and a second polymerization initiator, and
• optionally, a second organic solvent,
• the second marker material being detectably different from the first marker material,
• provided that at least one of the first and second water-in-oil emulsions contains an ethylenically unsaturated polymerizable monomer and a polymerization initiator,
• B) combining the first and second water-in-oil emulsions to form a third water-in-oil emulsion containing a mixture of the first and second oil phases and distinct droplets of the first and second aqueous phases,
• C) dispersing the third water-in-oil emulsion in a third aqueous phase containing a surface stabilizing agent to form a water-in-oil-in-water emulsion containing droplets of the third water-in-oil emulsion, which third water-in-oil emulsion droplets contain the distinct droplets of the first and second aqueous phases, and
• D) polymerizing the ethylenically unsaturated polymerizable monomers,
• to form a solidified precursor porous particle having a continuous solid phase and including an external particle surface, and first and second discrete pores being isolated from each other and dispersed within the continuous solid phase,
• removing, if present, the first and second organic solvents of the first and second oil phases from the water-in-oil emulsion, and
• isolating the precursor porous particle to provide a porous particle,
• the porous particle further comprising the first marker material in the first discrete pores, and the second marker material in the second discrete pores.