Multiparticulate crystalline drug compositions having controlled release profiles

1. A pharmaceutical composition providing controlled release of azithromycin, comprising a plurality of multiparticulates, said multiparticulates comprising said azithromycin wherein at least 70 wt % of said azithromycin is crystalline, a poloxamer and a glyceride having at least one alkylate substituent of at least 16 carbon atoms, wherein the weight ratio of poloxamer to glyceride ranges from about 0.01 to 0.50, and wherein said multiparticulates comprise crystalline azithromycin suspended in a mixture of said glyceride and poloxamer.

2. The composition of claim 1 wherein said azithromycin is azithromycin dihydrate.

3. The composition of claim 1 or claim 2 wherein at least 80 wt % of said azithromycin is crystalline.

4. The composition of claim 1 or claim 2 wherein said alkylate substituent is selected from the group consisting of palmitate, stearate, oleate, linoleate, arachidate, behenate, lignocerate, ricinoleate and mixtures thereof.

5. The composition of claim 1 or claim 2 wherein said glyceride is selected from the group consisting of: mixtures of glyceryl mono-, di-, and tribehenates; mixtures of glyceryl tripalmitate and glyceryl tristearate; glyceryl tri-behenates; and mixtures thereof.

6. The composition of claim 1 or claim 2 wherein said poloxamer is selected from the group consisting of poloxamer 188, poloxamer 237, poloxamer 338, poloxamer 407 and mixtures thereof.

7. The composition of claim 1 or claim 2 wherein said poloxamer has a molecular weight of at least 4,700 daltons.

8. The composition of claim 1 or claim 2 wherein said poloxamer is solid at ambient temperatures.

9. The composition of claim 1 or claim 2 wherein said poloxamer is homogeneously distributed throughout said glyceride.

10. A process for forming multiparticulates, comprising:

(a) forming a molten mixture comprising azithromycin, a poloxamer and a glyceride having at least one alkylate substituent of at least 16 carbon atoms, wherein said molten mixture has a viscosity less than about 20,000 cp and comprises crystalline azithromycin suspended in a mixture of said glyceride and poloxamer;

(b) forming droplets from said molten mixture; and

(c) solidifying said droplets to form multiparticulates

wherein at least 70 wt % of said azithromycin in said multiparticulates is crystalline, and

wherein the ratio of poloxamer to glyceride ranges from about 0.01 to 0.50.

11. The process of claim 10 wherein said azithromycin is azithromycin dihydrate.

12. The process of claim 10 or claim 11 wherein at least 80 wt % of said azithromycin in said multiparticulate is crystalline.

13. The process of claim 10 or claim 11 wherein said molten mixture has a viscosity of less than about 10,000 cp.

14. A method for controlling the release rate of azithromycin from a multiparticulate, comprising:

(a) determining a desired release rate of said azithromycin from said multiparticulate;

(b) forming multiparticulates comprising

(1) forming a molten mixture comprising crystalline azithromycin suspended in a mixture of a poloxamer and a glyceride having at least one alkylate substituent of at least 16 carbon atoms;

(2) forming droplets from said molten mixture; and

(3) solidifying said droplets to form multiparticulates wherein at least 70 wt % of said azithromycin in said multiparticulates is crystalline; and

(c) prior to (b) selecting a weight ratio of said poloxamer to said glyceride to achieve said desired release rate, wherein the weight ratio of poloxamer to glyceride ranges from about 0.01 to 0.50.

15. The method of claim 14 wherein said glyceride comprises at least 20 wt % of said multiparticulate.