USP Authorized Distributors

For your convenience, USP has authorized distribution by the entities listed below. To place an order, obtain ordering, pricing, and shipping information directly from your distributor. The USP products they carry are shown in italics below each listing.

As you know, USP Reference Standards can help you avoid extra work for characterizing, stability testing, lot expiry tracking, and traceability verification. Ask your distributor for further details about our Value beyond the Vial.

Click below to jump to each section:

Asia Europe Latin America Middle East Africa Australia/New Zealand

Bangladesh

Pasteur Pharmatech
Solutions Pte. Ltd. Singapore
(A subsidiary company of Pasteur
Pharmatech Solutions, Bangladesh.)
1 Soon Lee Street, #06-43/44
Pioneer Center, Singapore, 627606
Email: info@pasteursg.com,
website: www.pasteursg.com
Contact: +6564252271
PIC: Masudur Rahman
Cell: +8801716123519,
masud@pasteursg.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Chromachemie Laboratory
Pvt., Ltd.
VITC Export Bhavan, Plot No 488
B14th Cross, Peenya Industrial
AreaBangalore, Karnataka 560058
Tel: +91 80 2836 0616
uspenquiry@chromachemie.co.in
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

India

Pakistan

Chromachemie Laboratory
Private Limited
Dubai Office
Office No LB03001 Jebel Ali Free Zone.
PO Box: 127856, Dubai-UAE
Tel: +971 4 546 4843
dxb.enquiry@chromachemie.ae
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Hong Kong, China

Tin Hang Technology Limited
Units 1904-06, 19/F
No. 340 Queen’s Road CentralHONG KONG
Tel: +852 28172121
Fax: +852 25807763
Email: dennis@tinhangtech.com
sales@tinhangtech.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Indonesia

PT IMCD Indonesia
Gedung Puri 29
Jl. Lingkar Luar Barat, RT.05 RW.01
Kembangan Utara, Kembangan
Jakarta Barat 11610
Tel: +62 21 2952 7355
Fax: +62 21 2952 7353
E-mail: yenny.widya@imcd.co.id
URL: https://www.imcdgroup.com/en/worldwide/indonesia
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Japan

Fuji Chemicals Ltd.
2-6-11, Higashitenma, Kita-ku,
Osaka, 530-0044 JAPAN
Tel: +81-6-6358-0981
Fax: +81-6-6358-0986
E-mail:
y.yamamoto@fuji-chemicals.co.jp
URL:
https://www.fuji-chemicals.co.jp/en/
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Nihon Validation
Technologies Corp.
Koshigaya Yayoi Bldg. 2F YayoiCho 1-4, Koshigaya-Shi
Saitama 343-0816 JAPAN
Tel: (+81) 50-3536-1817
Fax: (+81) 48-964-9930
Email: ref_std@validation.co.jp
www.validation.co.jp
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Pharmaceutical and Medical
Device Regulatory Science
Society of Japan
2-1-2 Hiranomachi Chuo-ku,
Osaka-city Osaka 541-0046,
JAPAN Customer Service:
Tel: (+81) 6-6221-3444
Fax: (+81) 6-6221-3445
Order Receiving and Shipping:Tel:
(+81) 6-6221-3458
Fax: (+81) 6-6221-3459
Email: jprslab-std@pmrj.jp
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Korea

Daejung Chemicals & Metals Co., Ltd.
1235-8 Jeongwang-dong
Shiheung-city, Gyeonggi-do KOREA
Tel: (+82)-31-488-8822
Fax: (+82)-31-488-8966
Email: ejkim@daejung.kr
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Samchun Pure Chemical Co., Ltd.
117, Sandan-ro 16beon-gil
Pyeongtaek-city, Gyeonggi-do KOREA
Tel: +82-2-515-3081
Fax: +82-2-515-4066
Email: trade5@samchun.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Mainland China

Anhui Senrise Technology Co., Ltd.
Room 1206, Building 1, No. 515 Huanke Road,
Zhangjiang, Pudong New Area, Shanghai, China
Tel: 021-58432009
Email: service@energy-chemical.com
USP Pharmaceutical Analytical Impurities (PAI)

Alta Scientific Co., Ltd.
Tianda Science and Technology Park, Suite C6-3
80 The Fourth Street, TEDA, Tianjin 300457, P.R. China.
Tel: 86-22-65378550
Email: sales@altasci.com.cn
USP Reference Standards for Dietary Supplements/Herbal Medicines,
Excipients, Foods and General Chapters

Hechun Biotechnology(Shanghai) Co., Ltd
2F Room A03, G Building, No 258, Chenhui Road
Pudong New District, Shanghai,
CHINA 201203
Tel: +86 21 50706076
Email: xiaohy@hchbio.com
USP Reference Standards

Shenzhen Sungening Bio-Medical Co., Ltd
412 Room,Park 1, Shenzhen Oversea Students(Longgang)Venture park,
Qinglin West Road, Central City, Longcheng Street, Longgang District, China
Tel: 86-(0755) 2896 7200
Email: wxf@sungening.com
USP Reference Standards

ShenZhen Phystandard Bio-Tech Co., Ltd.
3rd Floor,QingChuangCheng D Block, ZhangKeng community
MinZhi Street,LongHua District
ShenZhen,GuangDong,China 518131
Tel: 0755-81789528
Email: purchasing@phystandard.com
USP Pharmaceutical Analytical Impurities (PAI)

Sinopharm ChemicalReagent Co.,
Ltd.
No.52 Ningbo Road Shanghai,CHINA 200002
Tel: 86-21-63792692
86-21-63792694
Email:
guyawen@sinopharm.com
wuchenwen@sinopharm.com
USP Reference Standards

Tianjin Yifang Supply Chain Management Co. Ltd.
NO.18 XinYe 8th Street
West Area of Binhai New Area Develop. Zone
300462 Tianjin, China
Tel: 400-185-8866
Email: caixingwang11@163.com
Website: https://www.yifanglab.com
USP Reference Standards

Chinese Taipei

Uni-Onward Corp.
3F-2, No. 93 Sec. 1
Wenhua 1st Road, Linkou Dist., New Taipei
City 244, CHINESE TAIPEI
Tel: (+886) 2-2600-0611
Fax (+886) 2-2600-0799
Email: cs@uni-onward.com.tw
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Myanmar

Bangkok Chemart Ltd.
Sampao Damnernpiriyakul
Pharmacist, Senior Executive
51/78 Moo 7 Bangna-Trad Hwy
KM.8, Bangkaew, Bangplee
Samuthprakarn 10540 THAILAND
Tel: (+66) 2 720 9557 to 9
Fax: (+66) 2 720 9997
Email: sam.bcm@gmail.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Philippines

AE Alchemists, Inc.
3 T. Sandico Street, Wakas Bocaue
3018, Bulacan PHILIPPINES
Tel: +63 917 516 6575;
+63 917 516 8397; +63 44 692 1333
al.thealchemists@gmail.com
alexiialipio@gmail.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Thailand

Bangkok Chemart Ltd.
Sampao Damnernpiriyakul
Pharmacist, Senior Executive
51/78 Moo 7 Bangna-Trad Hwy
KM.8, Bangkaew, Bangplee
Samuthprakarn 10540 THAILAND
Tel: (+66) 2 720 9557 to 9
Fax: (+66) 2 720 9997
Email: sam.bcm@gmail.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Vietnam

Pham Nguyen Trading CO.,LTD
Fax: (84-8) 38485653
Email: info@phamnguyen.com.vn
Website: www.phamnguyen.com.vn/
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Mekong Delta branch:
No. 1 Nguyen Van Linh Str
Ninh Kieu District, Can Tho City,
VIETNAM
Tel: (84-71) 3739545
Fax: (84-71) 3739646
Email:
cantho@chromatography.com.vn

Hanoi branch:
1A, 317 Alley, Hoang Hoa Tham Lieu
Giai, Ba Dinh District
Tel: (84-4) 3715 1357
Fax: (84-4) 3715 1358
Email: ha-noi@phamnguyen.com

Europe

Merck, KgaA
Frankfurter Straße 250
Darmstadt, 64293, Germany
Phone: +49 89 6513 0
Fax: +49 89 6513 1169
Email: standardsEU@sial.com
www.sigmaaldrich.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)
** All European countries
except Russia and Turkey

Labmix24 GmbH
Kesseldorfer Rott 24
46499 Hamminkeln, Germany
Phone: +49 2852 96064 00
Fax: +49 2852 96064 24
Email: info@labmix24.com
www.labmix24.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Eurofins PHAST GmbH
Kardinal-Wendel-Straße 16
66424 Homburg, Germany
Phone: +49 6841 9242-456
Fax: +49 6841 9242-888
reference-standards@phast.com
www.reference-standards.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

VWR international
Hilpertstraße 20a
64295 Darmstadt, Germany
Phone: +49 06151-39 72-0
www.vwr.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)
** All European countries
** All European countries
except Serbia, Kosovo,
Macedonia, Turkey and Russia;
and 3 Asian Countries: Armenia,
Azerbaijan and Georgia

Lennox, Laboratory Supplies Ltd.
John F Kennedy Drive, Naas Road
Dublin 12 D12 FP79, Ireland
Tel: +353 1 460 7600
Fax: +353 1 450 7906
E-mail: customerservice@lennox.ie
URL: www.lennox.ie
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

CIS

Analitik Kimya ve
Lab.Cih.San.Tic.Ltd.Sti.
Headquarter: Mahmutbey Mh Tasocagi Yolu
Cad. Solen Residence 19/4 A Blok No:109
PO:34218 Bagcilar / Istanbul / TURKEY
Tel: +90 212 659 98 70(Pbx)
Fax: +90 212 659 53 48
Email: info@analitikkimya.com.tr
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)
Uzbekistan, Turkmenistan and Kirgizstan

DPB New Brands LLP(affiliated
company of SmartChem GmbH,
Hamburg, Germany)
Kazakhstan, 050059/A15E3B3 Almaty, AlFarabi av., 7, BC “NurlyTau”, bl. 4A, of.38
Тел./Tel.: +7 (727) 3115200,
3115275, 3115276
Head of Sales Department:
Ekaterina Ismagulova
Mail:
info@new-brands.kz
info@smart-chem.de
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)
Kazakhstan, Uzbekistan and Turkmenistan

LLC ALSI LTD
8/20, Shovkunenka St., Ap. 51
Kyiv 03049 UKRAINE
Tel: +380 44 520 05 05
Fax: +380 44 245 32 24
Email: info@alsi.ua
Website: https://alsi.ua/
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)
Ukraine (excluding Crimea, Donetsk, and Luhansk regions)

Turkey

Azelis Tr Kimya End. Urn. Ith. Ihr.ve
Tic. San. A.S.
FSM. Mah. Poligon Cad.No :8A Buyaka 2
Sit. A Blok Kule -1 Kat :13 34771 Ümraniye /
İstanbul TURKEY
Tel: +90 (0)216 504 44 44
Fax: +90 (0)216 524 12 80/81
Email: info@azelis.com.tr
www.azelis.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Argentina

Carpe Scheider y Cia, S.A.
Godoy Cruz 2769, 5 Piso
1425 Buenos Aires ARGENTINA
Tel: (+54) 11-477-60477
Fax: (+54) 11-477-59619
Email: usp@carpescheider.com
https://carpescheider.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

EUROLAB S.A.
Jorge Newbery 3466, 8° piso (CP:
1427) Buenos Aires ARGENTINA
Tel: (+54) 11 4551 1818 y
Rotativas
Email: smorer@eurolab.com.ar
www.eurolabsa.com.ar
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Bolivia

Brazil

Hexis Cientifica Ltda.
Avenida Antonieta Piva Barranqueiros
385 Jundiai, Sao Paulo, Brazil
Tel: +55 (11) 4589-2622 
E-mail: USP@hexis.com.br
URL: https://www.hexis.com.br
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

LAS do Brasil, Ltda.
Av. V-8 Qd. 22 Lt. 25 Papillon Park
Ap. De Goiânia, Goiás—BRAZIL
CEP; 74952-560
CNPJ: 06.880.842/0001-61
Insc. Estadual: 10383862-7
Tel: (+55) 62-3085-1900
Fax: (+55) 62-3094-5553
Email: comercial@lasdobrasil.com.br
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Chile

CWO Chile SpA
Eliodoro Yanez 2972
Of.604 Providencia –
Santiago CHILE
Tel: +56942595773
Email: cwochile@cwochile.cl
www.cwochile.cl
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Grupo Mathiesen
Avenida del Parque 4265 Piso 3
Ciudad Empresarial - Huechuraba
CHILE
Tel: 56 2 2640 5600
Contact Person: Paola Vielma
Email: contacto@grupomathiesen.com
pvielma@grupomathiesen.com
www.grupomathiesen.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Colombia

Kimia Trading Ltda.
Carrera 27 No. 83-23 Bogotá, D.C.
COLOMBIA
Tel: (+57)1-2568164;
(+57)1-2518464
Fax: (+57)1-6184448
Email: info@kimiatrading.com.co
kimia@kimiatrading.com.co
www.kimiatrading.com.co
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Suministros Analíticos S.A.S.
Calle 18 # 77-67 Office 503-504 
Bogota, Colombia
Phone: (+57) 601 – 4068279
Cel: (+57) 3002790639
Email: operaciones@suministrosanaliticos.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Mexico

Conepre, S.A. de C.V.
Pioneros del Cooperativismo No 73
Col. México Nuevo
Atizapán de Zaragoza, Edo. de
México, C.P. 52966
MEXICO
Tel: (+52) 55 50-77-79-20
Email: ventas@conepre.com.mx
www.conepre.com.mx
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Proquifa
Calle Jose Maria Morelos No. 164
Barrio del Nino Jesús Tlalpan
D.F.C.P.14080 MEXICO
Tel/Fax: (5255) 1315-1498
Toll free in Mexico: 01-800-681-1440
Email: ventas@proquifa.com.mx
www.proquifa.com.mx
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Paraguay

EUROLAB S.A.
Jorge Newbery 3466, 8° piso (CP: 1427)
Buenos Aires ARGENTINA
Tel: (+54) 11 4551 1818 y Rotativas
Email: smorer@eurolab.com.ar
www.eurolabsa.com.ar
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Peru

JMC NC, Inc.
5842 Fayetteville Road Suite
120/119
Durham, NC 27713 USA
Tel:919-484-7555
Fax: 984-206-8995
Email: info@jmcinc.net
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Farma International
9400 South Dadeland Blvd. Suite
603
Miami, FL 33156 USATel: 305-670-
4416
Fax: 305-670-4417
Email: sales@farmainternational.com
www.farmainternational.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Proquifa
Av Santo Toribio 143, piso 5
San Isidro
Lima-Peru
Tel: (51)975133091
Email: mgudiel@proquifa.net
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Av Santo Toribio 143, piso 5
San Isidro
Lima-Peru
Tel: (51)975133091
Email: mgudiel@proquifa.net
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Uruguay

Venezuela

Carpe Scheider Y Cia S.A.
Godoy Cruz 2769, 5 Piso
1425 Buenos Aires ARGENTINA
Tel: (+54) 11-477-60477
Fax: (+54) 11-477-59619
Email: usp@carpescheider.com.ar
www.carpescheider.com.ar
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Kimia Trading Ltda.
Carrera 27 No. 83-23 Bogotá, D.C.
COLOMBIA
Tel: (+57)1-2568164;
(+57)1-2518464
Fax: (+57)1-6184448
Email:
info@kimiatrading.com.co
kimia@kimiatrading.com.co
www.kimiatrading.com.co
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Exporters to Central America, South America, and the Caribbean

Farma International
9400 South Dadeland Blvd.
Suite 603
Miami, FL 33156 USA
Tel: 305-670-4416
Fax: 305-670-4417
Email:
sales@farmainternational.com
www.farmainternational.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Exporter to Central America

Pharma Scientific
2820 San Bernardo Suite 9 Laredo,
TX 78045 USA
Tel: 956-729-8110
Fax: 956-729-8112
Email: sales@pharmascientific.net
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Israel

Rhenium Equipment for Research Lab Ltd.
20 Hasatat, P.O.B 180
Modi'in 7171101, Israel
Tel: +972-8-9558888
Fax: +972-8-996-9688
E-mail: cs@rhenium.co.il
URL: www.rhenium.co.il
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Jordan/Iraq/Lebanon/Gulf Area/West Bank/Gaza

Al Massat (Al Massat Lil
Tewridat Alkimawia LLC)
Amman Office
AL MASSAT LIL TEWRIDAT
ALKIMAWIA LTD
University Street , Abu AL-Hajj
Building
No.148 , 8th floor
Amman – Jordan
Tel : +962 6 5163886/7/8
Fax : +962 6 5163889
Mobile : +962 799174777
admin@al-massat.com
Pharma Global Dept.
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Saudi Arabia

Al Massat Life Sciences – KSA office
Ibn Katheer St 7783
Ground Floor office B-15
Riyadh 12233 – 4264
KSA
Tel : +966 54 896 3116
saudi@al-massat.com
www.al-massat.com
Pharma Global Dept.
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

UAE

Al Massat LIFE SCIENCES
DMCC
5465, Floor # 54, Almas Tower,
Jumeirah Lake Towers (JLT)
Dubai – United Arab Emirates
P O Box 112911
Tel: +971 4 383 5486
Mobile: +971 (0)528904484
Dubaioffice@al-massat.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Egypt/Sudan

Al Massat LIFE SCIENCES
EGYPT
Al Yasmeen 7, 1stSettlement
New Cairo
Cairo, Egypt
Tel: +202 23097751
Fax: +202 23097752
Email: Egyptoffice@al-massat.com
www.al-massat.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Tunisia/Algeria

Al Massat Life Sciences – Algeria office
14A Mohamed Bachouche St.
Al Mouradia – Algeria
Tel : +231 550 1483 41
northafrica@al-massat.com
www.al-massat.com / www.maskem.com
Pharma Global Dept.
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

South Africa/Kenya/Sub-Saharan Africa

Stargate Scientific
No. 3 Highcliff Office Park
53 Christiaan De Wet Road Ext. 3
Allen’s Nek, Roodepoort
1709 SOUTH AFRICA
Tel: +27 (0)11 675 7433
Fax: +27 (0)86 672 4989
Email: info@stargatescientific.co.za
www.stargatescientific.co.za
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Ethiopia/Uganda/Kenya/Rwanda/Tanzania

ABS International FZE
Level 14, Emaar Plaza Tower One
Emaar Boulevard, Downtown Dubai,
Dubai, UAE
Tel: +971 4 444 9456/971 50
8491066
Fax: +971 455 8566
Email: Abraniyous@absfze.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Stargate Scientific
No. 3 Highcliff Office Park
53 Christiaan De Wet Road Ext. 3
Allen’s Nek, Roodepoort
1709 SOUTH AFRICA
Tel: +27 (0)11 675 7433
Fax: +27 (0)86 672 4989
Email: info@stargatescientific.co.za
www.stargatescientific.co.za
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Ghana

LS Scientific Limited
Unit 112 Joseph Wilson Industrial Estate
Millstrood Road
Whitstable
Kent
United Kingdom
CT5 3SN
uksales@lsscientific.com
Tel: +441227200161
www.lsscientific.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Nigeria

LS Scientific Limited
50 Adeyemo Akapo Street
Omole Phase 1
Lagos, Nigeria
sales@lsscientific.com
Tel: 01-3429011
www.lsscientific.com
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Australia/New Zealand

ChemSupply Australia
50 Bedford street, Gillman,
South Australia 5015
Tel : +61 8 8440 2000
Fax : +61 8 8440 2001
Dean Jennins
Email: sales@chemsupply.com.au
www.chemsupply.com.au
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Merck Life Science Pty Ltd
Ground Floor, Building 1
885 Mountain Highway, Bayswater
Victoria, 3153, Australia
Toll Free: 1800 800 097
E-mail: CustomerSupport.ANZ@merckgroup.com
www.sigmaaldrich.com/AU/en
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Merck Life Science Ltd
Level 26 PwC Tower,
15 Customs Street West
Auckland, 1010, New Zealand
Toll Free: 0800 936 666
E-mail: CustomerSupport.ANZ@merckgroup.com
www.sigmaaldrich.com/NZ/en
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)

Bangladesh, Nepal, Sri Lanka

Chromachemie Laboratory Private Limited
Dubai Office
Office No LB03001 Jebel Ali Free Zone.
PO Box: 127856, Dubai-UAE
Tel: +971 4 546 4843
dxb.enquiry@chromachemie.ae
USP Reference Standards
USP Pharmaceutical Analytical Impurities (PAI)