( aS,yS,2S)-4-[1-[ 5-( 4-fluorophenyl)-2-oxazolyl]-1-meth› ylethyl ]-N-[ (3S,4S)-3,4-dihydro-3-hydroxy-2H-1-ben› zopyran-4-y 1 ]-a-( furo[2,3-c ]pyridin-2-y lmethy l)-y-hy› droxy-2-[[ (2,2,2-trifluoroethyl)amino ]carbonyl]-1- piperazinepentanamide; 

( aS,yS,2S)-4-[1-[ 5-( 4-chlorophenyl)-2-oxazolyl]-1-me› thylethyl]-N-[ (3S,4S)-3,4-dihydro-3-hydroxy-2H-1- benzopyran-4-y 1 ]-a-( furo[2,3-c ]pyridin-3-y lmethy l)-y› hydroxy-2-[[ (2,2,2-trifluoroethy l)amino ]carbonyl ]-1- piperazinepentanamide; 

( aS,yS,2S)-4-[1-[ 5-( 4-fluorophenyl)-2-oxazolyl]-1-meth› ylethyl ]-N-[ (3S,4S)-3,4-dihydro-3-hydroxy-2H-1-ben› zopyran-4-y 1 ]-a-( furo[2,3-c ]pyridin-3-y lmethy l)-y-hy› droxy-2-[[ (2,2,2-trifluoroethyl)amino ]carbonyl]-1- piperazinepentanamide; 

( aS,yS,2S)-N-[ (3S,4S)-3,4-dihydro-3-hydroxy-2H-1- benzopyran-4-y 1 ]-4-[ 1-[ 5-( 4-fluoropheny 1)-2-ox› azoly 1 ]-1-methy le thy 1 ]-a-( furo[2,3-d]pyrimidin-6-y l› methyl)-y-hydroxy-2-[[ (2,2,2-trifluoroethy l)amino] carbonyl ]-1-piperazinepentanamide; 

and pharmaceutically acceptable salts thereof. 

11. The composition according to claim 1, wherein the complex comprises Compound A or a pharmaceutically acceptable salt thereof, wherein Compound A is ( aR,yS,2S)- 4-[[ 5-( 5-chloro-2-pyridiny 1)-2-furany 1 ]me thy 1 ]-N-( (3S,4S)- 3,4-dihydro-3-hydroxy-2H-1-benzopyran-4-y l)-y-hydroxy› a-(phenylmethyl)-2-[[(2,2,2-trifluoroethyl)amino] carbonyl]-1-piperazinepentanamide. 

12. The composition according to claim 1, wherein the cation exchange resin is an acidic sulfonic acid resin or an acidic carboxylic acid resin. 

13. The composition according to claim 1, wherein the cation exchange resin is a strongly acidic resin. 

14. The composition according to claim 1, wherein the cation exchange resin is an acidic sulfonic acid resin. 

15. The composition according to claim 14, wherein the cation exchange resin is Amberlite IRP-69. 

16. The composition according to claim 15, wherein the Amberlite IRP-69 is complexed with Compound A or a pharmaceutically acceptable salt thereof, wherein Com› pound A is (aR,yS,2S)-4-[[5-(5-chloro-2-pyridinyl)-2-fura› nyl ]methyl]-N-((3S,4S)-3,4-dihydro-3-hydroxy-2H-1-ben› zopyran-4-yl)-y-hydroxy-a-(phenylmethyl)-2-[[(2,2,2- trifluoroethyl)amino ]carbonyl ]-1-piperazinepentanamide. 

17. The composition according to claim 1, which further comprises a capsule containing the complex. 

18. A method of inhibiting HIV protease in a subject in need thereof which comprises administering to the subject a therapeutically effective amount of the composition accord› ing to claim 1. 

19. A method of preventing or treating infection by HIV in a subject in need thereof which comprises administering to the subject a therapeutically effective amount of the composition according to claim 1. 

20. A method of treating or delaying the onset of AIDS in a subject in need thereof which comprises administering to the subject a therapeutically effective amount of the com› position according to claim 1. 

21. A process for preparing the composition according to claim 1 which comprises: 

(A) contacting a cation exchange resin with a compound of Formula (I) in an aqueous or polar organic medium under conditions and for a time sufficient for the compound to form a complex with the resin; and 

(B) recovering the complex. 

22. The process according to claim 21, wherein the cation exchange resin is an acidic sulfonic acid resin. 

23. The composition prepared by the process of claim 22. 

24. The complex formed by contacting a cation exchange resin with a compound of Formula (I) as defined in claim 1. 

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