Inclusion Criteria:

1. Healthy normal male or female subjects 18 to 65 years of age on Day -1 of the study
2. Subject must have read, understood, and provided written informed consent after the nature of the study has been fully explained and must be willing to comply with all study requirements and procedures
3. In the opinion of the Investigator, subjects should be in generally good health, based upon prestudy medical history, physical examination, ECG and laboratory tests (see Appendix H)
4. Laboratory screening values (i.e., hematology, clinical chemistries and urinalysis tests) must be within study-defined ranges (See Appendix G).
5. No detectable antibody to B. anthracis Protective Antigen (PA-IgG) as measured by ELISA testing at study Screening

6. Women of childbearing potential may be enrolled if one of the following criteria applies:

   1. Must be using an effective form of contraception (e.g., oral contraceptives,, IUD, injected or implanted hormonal contraception, double barrier method of condom and spermicide, diaphragm with spermicide or sponge with spermicide) for at least one month prior to study entry, must have maintained a normal menstrual pattern for the three months prior to study entry and have a negative pregnancy test at the time of admission to the unit. Women must be willing to continue this contraception throughout the course of the study.
   2. Is sexually abstinent
   3. Is monogamous with a vasectomized partner (> 3 months prior)
   4. Is postmenopausal (i.e., no cycle for at least the previous 12 months, is of menopausal age (> 45 years) and has a negative urine pregnancy test prior to enrollment into the study and a negative serum pregnancy test on Day -1)
   5. Is surgically sterilized (confirmed by medical record review)
   6. Has had a total hysterectomy a minimum of 3 months prior to dosing on Day 1 (confirmed by medical record review)

7. Sexually active male subjects may be enrolled if one of the following criteria applies:

   1. Has had a vasectomy (> 3 months prior to study entry, confirmed by medical record review)
   2. Using condoms and whose partner is using an acceptable form of contraception (IUD, oral contraceptives, birth control patch or vaginal ring, injectable or implanted contraceptives, or tubal ligation [surgical sterilization]) for the duration of the study
   3. Is sexually abstinent
8. Female subjects must have a negative urine pregnancy test at study Screening and a negative serum pregnancy test on admission to the Phase I unit at Day -1
9. Female subjects using injectable, transdermal, vaginal ring, oral contraceptives, or an IUD must agree to also use a barrier method (i.e. male condom, female condom, diaphragm, cervical cap) for the duration of their participation in the study.
10. Agreement to not receive any vaccinations from Day -1 through to 31 days post Valortim dosing. Vaccination against B. anthracis is prohibited during the study.
11. Body Mass Index (BMI) ≥ 19 and ≤ 30 (see Appendix C)
12. Abstinence from alcohol for 24 hours prior to study drug administration until discharge from the Phase I unit

Exclusion Criteria:

1. Prior known or suspected exposure to B. anthracis
2. Prior vaccination for B. anthracis
3. Any participants in the original FTIH study of Valortim.
4. History of drug or alcohol abuse i.e. having been treated either in an in-patient or out-patient facility within 12 months of study Screening
5. Positive drug result and/or positive alcohol result at time of study Screening or at Day -1
6. Smoke more than 10 cigarettes per day for the last 6 months
7. Treatment with an investigational agent within 30 days or 5 half-lives (whichever is longer) of study Screening
8. Use of systemic immunosuppressive agents within 12 months of study Screening. Individuals who have received prednisone or its equivalent in doses of less than 20 mg/day for 14 days or less, as long as it occurred more than 1 month prior to them entering the study and as long as there is no clinical or laboratory evidence of immunosuppression, may be considered for enrollment
9. Use of laxatives within 24 hours prior to dosing
10. Use of proton pump inhibitors within 72 hours prior to dosing
11. History of asthma requiring any use of inhaled or oral medication within the previous 5 years
12. History of hepatic or renal impairment or diabetes
13. Clinically significant medical or psychiatric condition that, in the opinion of the Investigator, may impair study participation to include ongoing recent illness, new medications prescribed in the previous 6 weeks or use of immunosuppressive agents
14. Electrocardiogram with evidence of clinically significant conduction abnormalities or active ischemia (as determined by the Principal Investigator) at the time of study screening
15. Donation of one or more pints of blood 30 days prior to study Screening visit or donation prior to completion of Day 34 of the study
16. Donation of plasma within 14 days prior to study Screening visit or donation prior to completion of Day 34 of the study
17. Vaccinations within 30 days prior to Day -1 through to 31 days post Valortim dosing on Day 6.
18. Prior known serum positivity for human immunodeficiency virus (HIV) antibodies, hepatitis B (surface antigen) or hepatitis C as determined at study Screening
19. Prior known allergy or allergic reaction to doxycycline or any of the group of antibiotics known as tetracyclines
20. Current treatment with, or use of, anticoagulants, antibiotics, barbiturates and anti-epileptic drugs
21. Diagnosis of photosensitivity, including, but not limited to, a history of phototoxic and/or photoallergic reactions to medications