Antibiotic formulation and method of treatment

Abstract

A formulation comprised of particles which may be in groups and are comprised of a biocompatible polymer and an antimicrobial drug for controlled release of the drug is disclosed. The particles may be in an aqueous solution comprising thrombin and be dispersed in a gel. The formulation is administered to an area such as an open wound having an orthopedic implant therein and provides a therapeutically effective level of drug to the patient over therapeutically effective period of time.

1 . A formulation, comprising: 
 a plurality of antimicrobial particles comprised of an antimicrobial drug and a biocompatible polymer; and    a pharmaceutically acceptable carrier having the antimicrobial particles dispersed therein.    
   
   
       2 . The formulation of  claim 1 , wherein the pharmaceutically acceptable carrier is a biocompatible gel and the formulation is implanted in a patient providing 35 mcg/ml ±25 mcg/ml of drug to a target area for a period of one day to seven days.  
   
   
       3 . The formulation of  claim 2 , further comprising: 
 a solution comprising water and thrombin.    
   
   
       4 . The formulation of  claim 1 , wherein the antimicrobial particles comprise: 
 a first group of spherical particles comprising 100 or more particles wherein each particle of the first group has the same diameter as other particles in the first group with a margin of error of ±10% or less;    a second group of spherical particles comprising 100 or more particles wherein each particle of the second group has the same diameter as other particles in the second group with a margin of error of ±10% or less;    wherein particles of the first group dissolve at a rate which is faster than a rate at which the particles of the second group dissolve and the formulation provides from 5 mcg/ml to 100 mcg/ml of antimicrobial drug to a target area.    
   
   
       5 . The formulation of  claim 4 , wherein the formulation is implanted with orthopedic hardware and the drug is at substantially undetectable levels at greater than 5 cm from the hardware.  
   
   
       6 . The formulation of  claim 4 , wherein the antimicrobial particles further comprise: 
 a third group of spherical particles comprising 100 or more particles wherein each particle of the third group has the same diameter as other particles in the third group with a margin of error of ±10% or less;    wherein particles of the third group dissolve at a rate different from a rate at which the particles of the first and second groups dissolve.    
   
   
       7 . The formulation of  claim 3 , wherein the biocompatible polymer is polylactic glycolic acid (PLGA), the antimicrobial is an amino glycoside, and the particles are dispersed in a gel.  
   
   
       8 . The formulation of  claim 4 , wherein the antimicrobial particles further comprise: 
 a plurality of additional groups of spherical particles comprising 100 or more particles wherein the particles of each additional group has the same diameter as other particles in that group with a margin of error of ±20% or less;    wherein particles of each additional group dissolve at a rate different from a rate at which the particles of other groups dissolve.    
   
   
       9 . The formulation of  claim 6 , 
 wherein the second group of particles have 1,000 square centimeters or more of surface area per 0.1 cm 3  of total particle volume per group of particles more than the first group of particles; and    wherein the third group of particles have 2,000 square centimeters or more of surface area per 0.1 cm 3  of total particle volume per group of particles more than the second group of particles.    
   
   
       10 . The formulation of  claim 6 , 
 wherein the second group of particles have 5,000 square centimeters or more of surface area per 0.1 cm 3  of total particle volume per group of particles more than the first group of particles; and    wherein the third group of particles have 10,000 square centimeters or more of surface area per 0.1 cm 3  of total particle volume per group of particles more than the second group of particles.    
   
   
       11 . The formulation of  claim 8 , wherein the particles of each group dissolve at a rate per unit of time which is different from a rate of dissolution of any other of the groups of particles by an amount of about 25% or more.  
   
   
       12 . The formulation of  claim 1 , wherein the antimicrobial drug is gentamicin and the particles are in an aqueous solution comprising thrombin and the solution and the carrier is a biocompatible gel.  
   
   
       13 . The formulation of  claim 8 , wherein the spherical particles in each group have a diameter in a range of from about 40 micrometers to about 2 micrometers.  
   
   
       14 . The formulation of  claim 8 , wherein the spherical particles in each group have a diameter in a range of from about 30 micrometers to about 4 micrometers.  
   
   
       15 . The formulation of  claim 6 , 
 wherein the second group of particles have 1,000 square centimeters or more of surface area per 0.1 cm 3  of total particle volume per group of particles more than the first group of particles; and    wherein a third group of particles have 2,000 square centimeters or more of surface area per 0.1 cm 3  of total particle volume per group of particles more than the second group of particles.    
   
   
       16 . The formulation of  claim 6 , 
 wherein the second group of particles have 5,000 square centimeters or more of surface area per 0.1 cm 3  of total particle volume per group of particles more than the first group of particles; and    wherein a third group of particles have 10,000 square centimeters or more of surface area per 0.1 cm 3  of total particle volume per group of particles more than the second group of particles.    
   
   
       17 . A surgical wound comprising an orthopedic implant and a formulation, comprising: 
 a biocompatible gel;    particles comprised of a biocompatible polymer and an antimicrobial drug wherein a target area around the orthopedic implant is provided with antimicrobial drug at a therapeutic level.    
   
   
       18 . The surgical wound of  claim 17 , wherein the target area extends to 5 cm from the orthopedic implant and the therapeutic level is 30 mcg/ml ±25 mcg/ml.  
   
   
       19 . The surgical wound of  claim 17 , wherein the formulation in the wound further comprises a thrombin solution.  
   
   
       20 . A method of treatment, comprising: 
 implanting an orthopedic implant into a surgical wound site;    administering to the wound site a formulation comprised of a plurality of particles which particles are comprised of an antimicrobial drug and a biocompatible polymer; and    allowing drug from the formulation to dissolve into the wound site over a period of time not less than one day and not more than seven days and provide a therapeutically effective dose of the drug over the period of time.    
   
   
       21 . The method of treatment of  claim 20 , wherein the therapeutically effective dose is in a range of 30 micrograms per milliliter ±25 micrograms per milliliter and the period of time is 72 hours ±12 hours.