This study is conducted to explore the safety and tolerability and plasma pharmacokinetics of NRL001 after single intra-anal dose of 1mL cream at increasing concentrations.

Inclusion Criteria:

IN.1) sex: male and female (non-child-bearing potential or using medically adequate contraception

IN.2) race: Caucasian

IN.3) BW: 50 - 100 kg

IN.4) BMI: 20 - 28 kg.m-2

IN.5) age: 21 - 50 years

IN.6) type: healthy on the basis of specified criteria evaluated at the screening visit

IN.7) willing and able to provide informed consent

Exclusion Criteria:

General

EX.1) Previous participation in the trial

EX.2) Participant in any other trial during the last 90 days

EX.3) Donation of blood during the last 60 days or a history of blood loss exceeding 300 mL within the last 3 months

EX.4) History of any clinically relevant allergy (including hypersensitivity to the trial medications)

EX.5) Presence of acute or chronic infection

EX.6) Presence or history of any relevant co-morbidity

EX.7) Resting systolic blood pressure > 140 or < 90 mmHg, diastolic blood pressure > 95 or < 50 mmHg

EX.8) Clinically relevant ECG-abnormalities, prolonged QTc with > 450 msec in males and > 460 msec in females in particular

EX.9) Presence of any relevant abnormality in the laboratory safety tests, especially low haemoglobin, increased liver enzymes

EX.10) Positive serology for HBsAg, anti HBc and anti HCV

EX.11) Positive HIV test

EX.12) Positive alcohol or urine drug test on recruitment (and upon admission)

EX.13) History of alcohol and/or drug abuse and/or daily use of > 30 gr alcohol

EX.14) Smoking more than 15 cigarettes/day or equivalent of other tobacco products

EX.15) Use of prohibited medication

EX.16) Suspicion or evidence that the subject is not trustworthy and reliable

EX.17) Suspicion or evidence that the subject is not able to make a free consent or to understand the information in this regard

General - all females

EX.18) Positive pregnancy test

EX.19) Lactating

EX.20) Not using appropriate contraception in pre-menopausal women (note: under the conditions of the present study, women using hormonal contraceptives will be informed that this method is not sufficient during the study and that further i.e. mechanical methods [condom, diaphragm with spermicidal gel] should be used in addition).