Pharmacokinetic, Safety, and Tolerability Study of Risperidone ISM® at Different Dose Strengths

This clinical trial will try to characterize and document the pharmacokinetics of risperidone ISM in schizophrenic or schizoaffective patients after one intramuscular injection at different dose strengths.Likewise, the safety and tolerability of risperidone ISM will be evaluated in the above mentioned population.

Following confirmation of eligibility and a washout period for study-prohibited drugs, a total of 33 subjects will be randomized in a 1:1:1 ratio to receive a single intramuscular (IM) injection of one of the following dosages of study drug:

Group 1: 50 mg risperidone ISM Group 2: 75 mg risperidone ISM Group 3: 100 mg risperidone ISM Several blood samples for plasma pharmacokinetic (PK) assessments will be obtained pre-dose and post-dose. Safety assessments will be conducted at each pre-specified time points.

Inclusion criteria

• Capable of providing informed consent.
• Male or female aged ≥ 18 years to < 65 years
• Current diagnosis of schizophrenia or schizoaffective disorder, according to the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders Clinical Trials (SCID-CT) or the DSM-IV-TR
• Medically stable over the last month, and psychiatrically stable without significant symptom exacerbation over the last three months based on the investigator's judgment
• Score of ≤ 4 (moderately ill) on the Clinical Global Impression - Severity of Illness (CGI-S)
• If a sexually active female of childbearing potential, using a medically accepted contraceptive method.

Exclusion criteria

• Presence of an uncontrolled, unstable, clinically significant medical condition that in the opinion of the investigator may interfere with the interpretation of safety and PK evaluations
• If female, a positive serum pregnancy test, or planning to become pregnant between now and one month after the last dose of trial medication, or currently breastfeeding a child
• History of neuroleptic malignant syndrome and current or past history of tardive dyskinesia
• Positive urine drug/alcohol screen finding, unless the positive finding can be accounted for by documented prescription use.
• In the investigator's opinion, at imminent risk of committing self-harm
• Use of depot antipsychotics within the last three months
• Receipt of any investigational drugs within the last three months
• Current participation in any other clinical trial