Valacyclovir free base

    WARNING: This product is for research use only, not for human or veterinary use.

MedKoo CAT#: 326809

CAS#: 124832-26-4 (free base)

Description: Valacyclovir, also known as valacyclovir, is an antiviral drug used in the management of herpes simplex, herpes zoster (shingles), and herpes B. It is a prodrug, being converted in vivo to aciclovir. Valaciclovir has been available as a generic drug in the U.S. since November 25, 2009. Valaciclovir is a prodrug, an esterified version of aciclovir that has greater oral bioavailability (about 55%) than aciclovir (10–20%). It is converted by esterases to the active drug aciclovir, as well as the amino acid valine, via hepatic first-pass metabolism. Aciclovir is selectively converted into a monophosphate form by viral thymidine kinase, which is far more effective (3000 times) in phosphorylation of aciclovir than cellular thymidine kinase.

Chemical Structure

Valacyclovir free base
CAS# 124832-26-4 (free base)

Theoretical Analysis

MedKoo Cat#: 326809
Name: Valacyclovir free base
CAS#: 124832-26-4 (free base)
Chemical Formula: C13H20N6O4
Exact Mass: 324.15
Molecular Weight: 324.341
Elemental Analysis: C, 48.14; H, 6.22; N, 25.91; O, 19.73

Price and Availability

This product is not in stock, which may be available by custom synthesis. For cost-effective reason, minimum order is 1g (price is usually high, lead time is 2~3 months, depending on the technical challenge). Quote less than 1g will not be provided. To request quote, please email to sales or click below button.
Note: Price will be listed if it is available in the future.

Related CAS #: 124832-26-4 (free base)   124832-27-5 (HCl)   950189-66-9 (maleate)    

Synonym: 256U87 hydrochloride; BW 256; BW-256; BW256; BW-256U87; Valacyclovir; valacyclovir. Val-ACV; Valtrex; Zelitrex; Valacyclovir HCl; Valacyclovir hydrochloride

IUPAC/Chemical Name: 2-((2-amino-6-oxo-1,6-dihydro-9H-purin-9-yl)methoxy)ethyl L-valinate


InChi Code: InChI=1S/C13H20N6O4/c1-7(2)8(14)12(21)23-4-3-22-6-19-5-16-9-10(19)17-13(15)18-11(9)20/h5,7-8H,3-4,6,14H2,1-2H3,(H3,15,17,18,20)/t8-/m0/s1


Appearance: Light yellow to yellow solid powder

Purity: >98% (or refer to the Certificate of Analysis)

Shipping Condition: Shipped under ambient temperature as non-hazardous chemical. This product is stable enough for a few weeks during ordinary shipping and time spent in Customs.

Storage Condition: Dry, dark and at 0 - 4 C for short term (days to weeks) or -20 C for long term (months to years).

Solubility: Soluble in DMSO

Shelf Life: >2 years if stored properly

Drug Formulation: This drug may be formulated in DMSO

Stock Solution Storage: 0 - 4 C for short term (days to weeks), or -20 C for long term (months).

HS Tariff Code: 2934.99.9001

More Info:

Biological target:
In vitro activity:
In vivo activity:

Preparing Stock Solutions

The following data is based on the product molecular weight 324.34 Batch specific molecular weights may vary from batch to batch due to the degree of hydration, which will affect the solvent volumes required to prepare stock solutions.

Recalculate based on batch purity %
Concentration / Solvent Volume / Mass 1 mg 5 mg 10 mg
1 mM 1.15 mL 5.76 mL 11.51 mL
5 mM 0.23 mL 1.15 mL 2.3 mL
10 mM 0.12 mL 0.58 mL 1.15 mL
50 mM 0.02 mL 0.12 mL 0.23 mL
Formulation protocol:
In vitro protocol:
In vivo protocol:

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1: Zhuang K, Wu Q, Ran X, Ran Y, Ding L, Xu X, Lei S, Lama J. Oral treatment with valacyclovir for HSV-2-associated eczema herpeticum in a 9-month-old infant: A case report. Medicine (Baltimore). 2016 Jul;95(29):e4284. doi: 10.1097/MD.0000000000004284. PubMed PMID: 27442669.

2: Kumar R, Sinha VR. Lipid Nanocarrier: an Efficient Approach Towards Ocular Delivery of Hydrophilic Drug (Valacyclovir). AAPS PharmSciTech. 2016 Jul 1. [Epub ahead of print] PubMed PMID: 27368921.

3: Nakatani M, Tsukino M, Takahashi R, Ikeda A. Periodic synchronous discharge occurred in an elderly with acute valacyclovir-associated encephalopathy. Rinsho Shinkeigaku. 2016 Jul 28;56(7):504-7. doi: 10.5692/ Epub 2016 Jun 30. PubMed PMID: 27356736.

4: Leruez-Ville M, Ghout I, Bussières L, Stirnemann J, Magny JF, Couderc S, Salomon LJ, Guilleminot T, Aegerter P, Benoist G, Winer N, Picone O, Jacquemard F, Ville Y. In utero treatment of congenital cytomegalovirus infection with valacyclovir in a multicenter, open-label, phase II study. Am J Obstet Gynecol. 2016 Apr 13. pii: S0002-9378(16)30044-8. doi: 10.1016/j.ajog.2016.04.003. [Epub ahead of print] PubMed PMID: 27083761.

5: Kervan U, Kucuker SA, Kocabeyoglu SS, Unal EU, Ozatik MA, Sert DE, Kavasoglu K, Tezer AY, Pac M. Low-Dose Valacyclovir for Cytomegalovirus Infection Prophylaxis After a Heart Transplant. Exp Clin Transplant. 2016 Mar 14. doi: 10.6002/ect.2015.0109. [Epub ahead of print] PubMed PMID: 26976362.

6: Gnann JW, Sköldenberg B, Hart J. Gnann JW et al (Clin Infect Dis 2015; 61:683-91). Herpes Simplex Encephalitis: Lack of Clinical Benefit of Long-term Valacyclovir Therapy. Clin Infect Dis. 2016 Feb 15;62(4):530. doi: 10.1093/cid/civ1011. Epub 2015 Dec 24. PubMed PMID: 26703861.

7: Staikuniene J, Staneviciute J. Long-term valacyclovir treatment and immune modulation for Herpes-associated erythema multiforme. Cent Eur J Immunol. 2015;40(3):387-90. doi: 10.5114/ceji.2015.54604. Epub 2015 Oct 15. Review. PubMed PMID: 26648786; PubMed Central PMCID: PMC4655392.

8: Anderson BJ, McGuire DP, Reed M, Foster M, Ortiz D. Prophylactic Valacyclovir to Prevent Outbreaks of Primary Herpes Gladiatorum at a 28-Day Wrestling Camp: A 10-Year Review. Clin J Sport Med. 2016 Jul;26(4):272-8. doi: 10.1097/JSM.0000000000000255. PubMed PMID: 26540599.

9: Singh SK, Prabhu A, Kumar A. Valacyclovir-induced urticaria without acyclovir hypersensitivity. Indian J Dermatol Venereol Leprol. 2015 Nov-Dec;81(6):611-2. doi: 10.4103/0378-6323.168346. PubMed PMID: 26515842.

10: Kechagia IA, Kalantzi L, Dokoumetzidis A. Extrapolation of Valacyclovir Posology to Children Based on Pharmacokinetic Modeling. Pediatr Infect Dis J. 2015 Dec;34(12):1342-8. doi: 10.1097/INF.0000000000000910. PubMed PMID: 26379165.

11: Canivet C, Menasria R, Rhéaume C, Piret J, Boivin G. Valacyclovir combined with artesunate or rapamycin improves the outcome of herpes simplex virus encephalitis in mice compared to antiviral therapy alone. Antiviral Res. 2015 Nov;123:105-13. doi: 10.1016/j.antiviral.2015.09.007. Epub 2015 Sep 14. PubMed PMID: 26374952.

12: Lee HJ, Kim JM, Kim GW, Mun JH, Song M, Kim HS, Kim BS, Kim MB, Ko HC. Fixed drug eruption due to acyclovir, valacyclovir and famciclovir. J Eur Acad Dermatol Venereol. 2015 Sep 15. doi: 10.1111/jdv.13261. [Epub ahead of print] PubMed PMID: 26369523.

13: Cunha BA, Baron J. The pharmacokinetic basis of oral valacyclovir treatment of herpes simplex virus (HSV) or varicella zoster virus (VZV) meningitis, meningoencephalitis or encephalitis in adults. J Chemother. 2015 Aug 4:1973947815Y0000000065. [Epub ahead of print] PubMed PMID: 26239190.

14: Ong SY, Truong HT, Diong CP, Linn YC, Ho AY, Goh YT, Hwang WY. Use of Valacyclovir for the treatment of cytomegalovirus antigenemia after hematopoietic stem cell transplantation. BMC Hematol. 2015 Jun 19;15:8. doi: 10.1186/s12878-015-0028-2. eCollection 2015. PubMed PMID: 26090121; PubMed Central PMCID: PMC4471913.

15: Tyler KL. Editorial Commentary: Failure of Adjunctive Valacyclovir to Improve Outcomes in Herpes Simplex Encephalitis. Clin Infect Dis. 2015 Sep 1;61(5):692-4. doi: 10.1093/cid/civ373. Epub 2015 May 8. PubMed PMID: 25956893.

16: Gnann JW Jr, Sköldenberg B, Hart J, Aurelius E, Schliamser S, Studahl M, Eriksson BM, Hanley D, Aoki F, Jackson AC, Griffiths P, Miedzinski L, Hanfelt-Goade D, Hinthorn D, Ahlm C, Aksamit A, Cruz-Flores S, Dale I, Cloud G, Jester P, Whitley RJ; National Institute of Allergy and Infectious Diseases Collaborative Antiviral Study Group. Herpes Simplex Encephalitis: Lack of Clinical Benefit of Long-term Valacyclovir Therapy. Clin Infect Dis. 2015 Sep 1;61(5):683-91. doi: 10.1093/cid/civ369. Epub 2015 May 8. Erratum in: Clin Infect Dis. 2016 Feb 15;62(4):530. Dosage error in article text. PubMed PMID: 25956891; PubMed Central PMCID: PMC4542890.

17: Katakam P, Dey B, Hwisa NT, Assaleh FH, Chandu BR, Singla RK, Mitra A. An Experimental Design Approach for Impurity Profiling of Valacyclovir-Related Products by RP-HPLC. Sci Pharm. 2014 May 5;82(3):617-9. doi: 10.3797/scipharm.1403-20. eCollection 2014 Sep. PubMed PMID: 25853072; PubMed Central PMCID: PMC4318202.

18: Kacer M, Kielberger L, Bouda M, Reischig T. Valganciclovir versus valacyclovir prophylaxis for prevention of cytomegalovirus: an economic perspective. Transpl Infect Dis. 2015 Jun;17(3):334-41. doi: 10.1111/tid.12383. Epub 2015 May 26. PubMed PMID: 25824586.

19: Kechagia IA, Dokoumetzidis A. Development of a paediatric population pharmacokinetic model for valacyclovir from literature non-compartmental values originating from sparse studies and Bayesian priors: a simulation study. J Pharmacokinet Pharmacodyn. 2015 Jun;42(3):237-50. doi: 10.1007/s10928-015-9412-6. Epub 2015 Mar 29. PubMed PMID: 25821006.

20: Upadhyay P, Nayak K, Patel K, Patel J, Shah S, Deshpande J. Formulation development, optimization, and evaluation of sustained release tablet of valacyclovir hydrochloride by combined approach of floating and swelling for better gastric retention. Drug Deliv Transl Res. 2014 Dec;4(5-6):452-64. doi: 10.1007/s13346-014-0207-x. PubMed PMID: 25787207.