Effect of Hydroxychloroquine Sulphate in Healthy Lean Females

Inclusion Criteria: * Subject is female between 18 and 65 years of age. * Subject has a BMI between 18 and 25 kg/m² and has a stable body weight for at least 3 consecutive months at the start of the study and keeps a stable weight during the study visits. * Subject is allowed to take 2 Plaquenil capsuls for one visit with a maximal dose of 6.5 mg hydroxychloroquine sulphate per kg bodyweight. * Women of child-bearing potential agree to apply during the entire duration of the trial a highly effective method of birth control, which is defined as those which result in a low failure rate (i.e., less than 1% per year) when used constantly and correctly such as implants, injectables, combined oral contraceptive method, or some intrauterine devices (IUDs), sexual abstinence, or vasectomized partner. Women of non-childbearing potential may be included if surgically sterile (tubal ligation or hysterectomy) or postmenopausal with at least 2 year without spontaneous menses. * Subject understands the study procedures and agrees to participate in the study by giving written informed consent. Exclusion Criteria: * Subject is under age of legal consent, male, pregnant or breastfeeding. * Subject with a BMI ≥ 18 kg/m² or BMI ≤ 25 kg/m². * Subject has current symptoms or a history of gastrointestinal or other significant somatic or psychiatric diseases or drug allergies. * Subject has diabetes. * Subject has a significant heart, lung, liver or kidney disease. * Subject has a QT-interval \> 450 ms. * Subject has any history of a neurological disorder. * Subject has a history of abdominal surgery. Those having undergone a simple appendectomy more than 1 year prior to the screening visit may participate. * Subject has retinopathy. * Subject suffers from psoriasis. * Subject has porphyria. * Subject shows abnormal eating behavior or has an eating disorder. * History or current use of drugs that can affect glycaemia, gastrointestinal function, motility or sensitivity or gastric acidity. * History or current use of centrally acting medication, including antidepressants, antipsychotics and/or benzodiazepines (in the last year before screening visit). * Subject consumes excessive amounts of alcohol, defined as \>14 units per week. * Subject is currently (defined as within approximately 1 year of the screening visit) a regular or irregular user (including "recreational use") of any illicit drugs (including marijuana) or has a history of drug (including alcohol) abuse. Further, patient is unwilling to refrain from the use of drugs during this study. * High caffeine intake (\> 500 ml coffee daily or equivalent). * Inability or unwillingness to perform all of the study procedures, or the subject is considered unsuitable in any way by the principal investigator. * Recent participation (\<30 days) or simultaneous participation in another clinical study. * Subjects with lactose intolerance. * Subjects with quinine allergy.