Provided herein are methods comprising providing a tyrosine derivative and a solid particulate material (and, optionally, melanin) and applying force to said tyrosine derivative and said solid particulate material for a time and under conditions effective to impregnate at least one of said tyrosine derivative and said solid particulate material with the other of said tyrosine derivative and said solid particulate material. The invention also provides compositions comprising at least one of a tyrosine derivative impregnated with a solid particulate material and a solid particulate material impregnated with a tyrosine derivative.
