The purpose of this study is to

1. Compare and evaluate the single-dose bioavailability study of 1000mg Valacyclovir HCl tablets of Dr. Reddy's and Valtrex (R)(Valacyclovir Hydrochloride)CAPLETS 1 gram of GlaxoSmithkline, in healthy, adult human subjects under fasting conditions.
2. monitor the adverse events and ensure the safety of subjects.

An open label, balanced, randomized, two-treatment, two-sequence two-period, single-dose, crossover comparative bioavailability study of 1000 mg Valacyclovir Hydrochloride Tablets of Dr. Reddy's Laboratories Ltd., India and valtrex (R) (Valacyclovir Hydrochloride) CAPLETS 1 gram of GlaxoSmithkline in healthy, adult human subjects under fasting conditions

Inclusion Criteria:

The subjects were selected for study participation, based on the following criteria:

1. Human subjects aged between 18 and 45 years (including both).
2. Subjects' weight within the normal range according to normal values for the Body Mass Index (18.5 to 24.9 kg/m2) with minimum of 50 kg weight.
3. Subjects with normal health as determined by personal medical history, clinical examination and laboratory examinations within the clinically acceptable normal range.
4. Subjects having normal 12-lead electrocardiogram (ECG).
5. Subjects having normal chest X-Ray (PIA view).
6. Have a negative urine screen for drugs of abuse (including amphetamines, barbiturates, benzodiazepines, marijuana, cocaine, and morphine).
7. Have negative alcohol breath test.
8. Subjects willing to adhere to the protocol requirements and to provide written informed consent.

Exclusion Criteria:

The subjects were excluded from the study, based on the following criteria:

1. Hypersensitivity to Valacyclovir Hydrochloride or related drugs.
2. History or presence of significant cardiovascular, pulmonary, hepatic, renal, gastrointestinal, endocrine, immunological, dermatological, neurological or psychiatric disease or disorder.
3. History or presence of significant alcoholism or drug abuse in the past one year.
4. History or presence of significant smoking (more than 10 cigarettes or beedi' s/day).
5. History or presence of significant asthma, urticaria or other allergic reactions.
6. History or presence of significant gastric and/or duodenal ulceration.
7. History or presence of significant thyroid disease, adrenal dysfunction, organic intracranial lesion such as pituitary tumour.
8. History or presence of cancer.
9. Difficulty with donating blood.
10. Difficulty in swallowing solids like tablets or capsules.
11. Systolic blood pressure less than 100 mm Hg or more than 140 mm Hg.
12. Diastolic blood pressure less than 60 mm Hg or more than 90 mm Hg.
13. Pulse rate less than 50/minute or more than 100/minute.
14. Oral temperature less than 95°F or more than 98.6°F.
15. Respiratory rate less than 12/minute or more than 20/minute
16. Subjects who have used any prescription medication, within 14 days of period 01 dosing or OTC medication within 14 days of period 01 dosing.
17. Major illness during 3 months before screening.
18. Participation in a drug research study within past 3 months.
19. Donation of blood in the past 3 months before screening.
20. Subjects who have consumed xanthine-containing products (including caffeine, theobromines, etc.) within 48 hours prior to period 01 dosing.
21. Subjects who have consumed food or beverages containing grapefruit or pomelo within 14 days prior to period 01 dosing.
22. Subjects who have used any drugs or substances known to be strong inhibitors of CYP enzymes (formerly known as cytochrome P450 enzymes) within 28 days prior to the first dose.
23. Subjects who have used any drugs or substances known to be strong inducers of CYP enzymes (formerly known as cytochrome P450 enzymes) within 28 days prior to the first dose.