ritonavir and its Impurities
An antiretroviral medication, used to treat HIV/AIDS in combination with other medicines. Ritonavir works as an inhibitor of HIV protease that interferes with the reproductive cycle of HIV. Reference standards of Ritonavir API,and its pharmacopeial, non pharmacopeial impurities, and stable isotopes are listed below.


Ritonavir - Impurity L (Freebase)
(2S)-3-Methyl-2-(((methyl((2-(1-methylethyl)-1,3-thiazol4-yl)methyl)amino)carbonyl)amino)-N-((1S)-2-((4S,5S)-2-oxo-4-(phenylmethyl)-1,3-oxazolidin-5-yl)-1-(phenylmethyl)ethyl)butanamide
Catalogue No.:PA 18 30120
CAS :
256328-82-2
Molecular Formula : C33H43N5O4S
Molecular Weight : 605.79


Ritonavir - Impurity Q
Thiazol-5-ylmethyl [(1S,2R,4R)-1-benzyl-2-hydroxy-4-[[(2S)-3-methyl-2-[[methyl[[2-(1-methylethyl)thiazol-4-yl]methyl]carbamoyl]amino]butanoyl]amino]-5-phenylpentyl]carbamate
Catalogue No.:PA 18 30170
CAS :
1414933-82-6
Molecular Formula : C37H48N6O5S2
Molecular Weight : 720.94


Ritonavir - Impurity S
Thiazol-5-ylmethyl [(1S,2S,4S)-1-benzyl-4-[[(2S)-2-[[[(1S,3S,4S)-1-benzyl-3-hydroxy-5-phenyl-4-[[(thiazol-5-ylmethoxy)carbonyl]amino]pentyl]carbamoyl]amino]-3-methylbutanoyl]amino]-2-hydroxy-5-phenylpentyl]carbamate
Catalogue No.:PA 18 30190
CAS :
2084828-53-3
Molecular Formula : C52H61N7O8S2
Molecular Weight : 976.21


Ritonavir - Impurity U
(1S,3S)-3-[[(2S)-3-Methyl-2-[[methyl[[2-(1-methylethyl)thiazol-4-yl]methyl]carbamoyl]amino]butanoyl]amino]-4-phenyl-1-[(1S)-2-phenyl-1-[[(thiazol-5-ylmethoxy)carbonyl]amino]ethyl]butyl (2S)-3-methyl-2-[[methyl[[2-(1-methylethyl)thiazol-4-yl]methyl]carbamoyl]amino]butanoate
Catalogue No.:PA 18 30210
CAS :
NA
Molecular Formula : C51H69N9O7S3
Molecular Weight : 1016.34


(3S,6S,8S,9S)-8-Hydroxy-3-(1-methylethyl)-4,11-dioxo-6,9-bis(phenylmethyl)-13-(5-thiazolyl)-12-oxa-2,5,10-triazatridecanoic Acid 2,3-Dihydroxypropyl Ester
(3S,6S,8S,9S)-8-Hydroxy-3-(1-methylethyl)-4,11-dioxo-6,9-bis(phenylmethyl)-13-(5-thiazolyl)-12-oxa-2,5,10-triazatridecanoic Acid 2,3-Dihydroxypropyl Ester
Catalogue No.:PA 18 30540
CAS :
1010809-54-7
Molecular Formula : C32H42N4O8S
Molecular Weight : 642.77

![N-[[N-Methyl-N-[(2-isopropyl-1,1,1,3,3,3-d6]-4-thi PA STI 062310](https://www.pharmaffiliates.com/pimages/PASTI062310.jpg)
N-[[N-Methyl-N-[(2-isopropyl-1,1,1,3,3,3-d6]-4-thiazolyl)methyl)amino]carbonyl-L-valine Carboxylic Acid
N-[[N-Methyl-N-[(2-isopropyl-1,1,1,3,3,3-d6]-4-thiazolyl)methyl)amino]carbonyl-L-valine Carboxylic Acid
Catalogue No.:PA STI 062310
CAS :
1331906-73-0
Molecular Formula : C14H17D6N3O3S
Molecular Weight : 319.45

![N-[[N-Methyl-N-[(2-isopropyl-1,1,1,3,3,3-d6]-4-thi PA STI 062320](https://www.pharmaffiliates.com/pimages/PASTI062320.jpg)
N-[[N-Methyl-N-[(2-isopropyl-1,1,1,3,3,3-d6]-4-thiazolyl)methyl)amino]carbonyl-L-valine Methyl Ester
N-[[N-Methyl-N-[(2-isopropyl-1,1,1,3,3,3-d6]-4-thiazolyl)methyl)amino]carbonyl-L-valine Methyl Ester
Catalogue No.:PA STI 062320
CAS :
1331897-89-2
Molecular Formula : C15H19D6N3O3S
Molecular Weight : 333.48


Ritonavir - Impurity N
Thiazol-5-ylmethyl [(1S,3S,4S)-1-benzyl-3-hydroxy-4-[[(2S)-3-methyl-2-[[methyl[[2-(1-methylethyl)thiazol-4- yl]methyl]carbamoyl]amino]butanoyl]amino]-5-phenylpentyl]carbamate
Catalogue No.:PA 18 30140
CAS :
202816-62-4
Molecular Formula : C37H48N6O5S2
Molecular Weight : 720.95


Ritonavir - Impurity O
Thiazol-5-ylmethyl [(1S,2R,4S)-1-benzyl-2-hydroxy-4-[[(2S)-3-methyl-2-[[methyl[[2-(1-methylethyl)thiazol-4-yl]methyl]carbamoyl]amino]butanoyl]amino]-5-phenylpentyl]carbamate
Catalogue No.:PA 18 30150
CAS :
1414933-81-5
Molecular Formula : C37H48N6O5S2
Molecular Weight : 720.95


Ritonavir - Impurity T
(2S)-N-[(1S,2S,4S)-1-Benzyl-2-hydroxy-4-[[(2S)-3-methyl-2-[[methyl[[2-(1-methylethyl)thiazol-4-yl]methyl]carbamoyl]amino]butanoyl]amino]-5-phenylpentyl]-3-methyl-2-[[methyl[[2-(1-methylethyl)thiazol-4-yl]methyl]carbamoyl]amino]butanamide
Catalogue No.:PA 18 30200
CAS :
869368-48-9
Molecular Formula : C46H66N8O5S2
Molecular Weight : 875.21


Thiazol-5-ylmethyl ((2S,3S,5S)-5-((S)-2-((ethoxycarbonyl)amino)-3-methylbutanamido)-3-hydroxy-1,6-diphenylhexan-2-yl)carbamate
Thiazol-5-ylmethyl ((2S,3S,5S)-5-((S)-2-((ethoxycarbonyl)amino)-3-methylbutanamido)-3-hydroxy-1,6-diphenylhexan-2-yl)carbamate
Catalogue No.:PA 18 30550
CAS :
NA
Molecular Formula : C31H40N4O6S
Molecular Weight : 596.74


Thiazol-5-ylmethyl ((5S,6S,8S,11S,15S,17S,18S)-5,8,15-tribenzyl-6,17-dihydroxy-11-isopropyl-3,10,13-trioxo-19-phenyl-1-(thiazol-5-yl)-2-oxa-4,9,12,14-tetraazanonadecan-18-yl)carbamate
Thiazol-5-ylmethyl ((5S,6S,8S,11S,15S,17S,18S)-5,8,15-tribenzyl-6,17-dihydroxy-11-isopropyl-3,10,13-trioxo-19-phenyl-1-(thiazol-5-yl)-2-oxa-4,9,12,14-tetraazanonadecan-18-yl)carbamate
Catalogue No.:PA 18 30600
CAS :
2084828-53-3
Molecular Formula : C52H61N7O8S2
Molecular Weight : 976.22


Thiazol-5-ylmethyl ((2S,3S,5S)-5-((S)-2-(3,3-dimethylureido)-3-methylbutanamido)-3-hydroxy-1,6-diphenylhexan-2-yl)carbamate
Thiazol-5-ylmethyl ((2S,3S,5S)-5-((S)-2-(3,3-dimethylureido)-3-methylbutanamido)-3-hydroxy-1,6-diphenylhexan-2-yl)carbamate
Catalogue No.:PA 18 30620
CAS :
959351-57-6
Molecular Formula : C31H41N5O5S
Molecular Weight : 595.76


Carbamic acid, [(1R,3S,4S)-4-amino-3-hydroxy-5-phenyl-1-(phenylmethyl)pentyl]-, 1,1-dimethylethyl ester
Carbamic acid, [(1R,3S,4S)-4-amino-3-hydroxy-5-phenyl-1-(phenylmethyl)pentyl]-, 1,1-dimethylethyl ester
Catalogue No.:PA 18 0301009
CAS :
220887-41-2
Molecular Formula : C23H32N2O3
Molecular Weight : 384.52


N-[(1S,3S,4R)-4-Amino-3-hydroxy-5-phenyl-1-(phenylmethyl)pentyl]-, 1,1-dimethylethyl ester
N-[(1S,3S,4R)-4-Amino-3-hydroxy-5-phenyl-1-(phenylmethyl)pentyl]-, 1,1-dimethylethyl ester
Catalogue No.:PA 18 0301011
CAS :
1414933-91-7
Molecular Formula : C23H32N2O3
Molecular Weight : 384.52


Thiazol-5-ylmethyl ((2R,3R,5R)-3-hydroxy-5-((S)-2-(3-((2-isopropylthiazol-4-yl)methyl)-3-methylureido)-3-methylbutanamido)-1,6-diphenylhexan-2-yl)carbamate
Thiazol-5-ylmethyl ((2R,3R,5R)-3-hydroxy-5-((S)-2-(3-((2-isopropylthiazol-4-yl)methyl)-3-methylureido)-3-methylbutanamido)-1,6-diphenylhexan-2-yl)carbamate
Catalogue No.:PA 18 0301013
CAS :
NA
Molecular Formula : C37H48N6O5S2
Molecular Weight : 720.95


Ethyl ((S)-1-(((2S,4S,5S)-4-hydroxy-1,6-diphenyl-5-(((thiazol-5-ylmethoxy)carbonyl)amino)hexan-2-yl)amino)-3-methyl-1-oxobutan-2-yl)carbamate
Ethyl ((S)-1-(((2S,4S,5S)-4-hydroxy-1,6-diphenyl-5-(((thiazol-5-ylmethoxy)carbonyl)amino)hexan-2-yl)amino)-3-methyl-1-oxobutan-2-yl)carbamate
Catalogue No.:PA 18 0301014
CAS :
NA
Molecular Formula : C31H40N4O6S
Molecular Weight : 596.74


Thiazol-5-ylmethyl ((2S,3S,5R)-5-((S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanamido)-3-hydroxy-1,6-diphenylhexan-2-yl)carbamate
Thiazol-5-ylmethyl ((2S,3S,5R)-5-((S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanamido)-3-hydroxy-1,6-diphenylhexan-2-yl)carbamate
Catalogue No.:PAI 18 008022
CAS :
NA
Molecular Formula : C33H44N4O6S
Molecular Weight : 624.8


Thiazol-5-ylmethyl ((2R,3S,5S)-3-hydroxy-5-((S)-2-(3-((2-isopropylthiazol-4-yl)methyl)-3-methylureido)-3-methylbutanamido)-1,6-diphenylhexan-2-yl)carbamate
Thiazol-5-ylmethyl ((2R,3S,5S)-3-hydroxy-5-((S)-2-(3-((2-isopropylthiazol-4-yl)methyl)-3-methylureido)-3-methylbutanamido)-1,6-diphenylhexan-2-yl)carbamate
Catalogue No.:PA 18 0301030
CAS :
241486-86-2
Molecular Formula : C37H48N6O5S2
Molecular Weight : 720.95