Paliperidone: a review of clinical trial data and clinical implications

Paliperidone-loaded nose to brain targeted NLCS: optimisation, evaluation, histopathology and pharmacokinetic estimation for schizophernia

Study was to develop a nanostructured-lipid-careers (NLCs) of paliperidone (PLP) for nose-to-brain targeting. NLCs was prepared by sonication, high-shear homogenisation method, and characterised their mean diameter, PDI, zeta-potential, morphology (by SEM, TEM and AFM), entrapment efficiency, drug loading, in vitro release, interaction study (by FTIR), and stability. Further, ex vivo permeation and ciliotoxicity performed in sheep nasal mucosa, and in vivo biodistribution/pharmacokinetic was performed in rats for schizophernia. Developed NLCs showed spherical and clearly 3-dimentinal structure with 129 ± 2.7 nm mean diameter, 0.304 ± 0.003 PDI, -7.61 ± 0.56 mV zeta-potential, 58.16 ± 0.17% entrapment efficiency, 65.8 ± 2% drug loading and 74.32 ± 0.003% release in 12 h, followed by Higuchi model. Ex vivo study showed NLCs have three times higher permeation, compare to pure drug (around 71.50.32% in 6 h) and 3.98 g/cm2/h steady sate flux. The blood/brain ratio given by intranasally have higher compare to IV route, and 94.53 ± 21.45% drug targeting efficiency in brain. In conclusion, NLCs have easily crossed BBB, higher drug delivery and effective for schizophrenia in given by intranasal.

Randomized Controlled Trial of Paliperidone Extended Release Versus Risperidone for the Treatment of Methamphetamine-Associated Psychosis in Chinese Patients

BACKGROUND

The efficacy or tolerability of paliperidone extended release (ER) in the treatment of methamphetamine (METH)-associated psychosis (MAP) is unknown. This study was designed to assess the tolerability and efficacy of paliperidone ER and risperidone for the treatment of MAP in China.

METHODS

This 25-day randomized clinical trial involved 120 patients with acute MAP symptoms who were randomized to receive either paliperidone ER or risperidone from baseline to day 25 of an inpatient hospital stay. The primary outcome was changes in the severity of psychosis, which were assessed using the Positive and Negative Syndrome Scale (PANSS) total score changes from baseline to endpoint.

RESULTS

Overall, 84% of the patients completed the entire study protocol. The PANSS total score, the Clinical Global Impressions-Severity of Illness scale (CGI-S) score, and a METH craving score assessed by a visual analog scale (VAS) showed statistically significant improvements from baseline for the patients in both groups (p < 0.01). The Simpson-Angus Scale (SAS) and the Barnes Akathisia Rating Scale (BARS) scores increased from baseline during treatment in both groups (p < 0.01); there were statistically significant differences between the treatment groups in the SAS scores (p < 0.01). Measures of hypermyotonia, salivation, and dizziness were significantly higher in the risperidone-treated patients than in the paliperidone ER-treated patients (all p < 0.05).

CONCLUSION

Paliperidone ER and risperidone had similar efficacy and were generally tolerable in the treatment of MAP; however, paliperidone ER had a more favorable adverse event profile than risperidone, particularly regarding extrapyramidal and prolactin-increasing effects.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, identifier NCT01822730. Full date of first registration:03/28/2013.

Immunoendocrine Peripheral Effects Induced by Atypical Antipsychotics

Atypical antipsychotics (AAP) or second-generation antipsychotics are the clinical option for schizophrenia treatment during acute psychoses, but they are also indicated for maintenance during lifetime, even though they are being used for other psychiatric conditions in clinical practice such as affective disorders and autism spectrum disorder, among others. These drugs are differentiated from typical antipsychotics based on their clinical profile and are a better choice because they cause fewer side effects regarding extrapyramidal symptoms (EPS). Even though they provide clear therapeutic benefits, AAP induce peripheral effects that trigger phenotypic, functional, and systemic changes outside the Central Nervous System (CNS). Metabolic disease is frequently associated with AAP and significantly impacts the patient's quality of life. However, other peripheral changes of clinical relevance are present during AAP treatment, such as alterations in the immune and endocrine systems as well as the intestinal microbiome. These less studied alterations also have a significant impact in the patient's health status. This manuscript aims to revise the peripheral immunological, endocrine, and intestinal microbiome changes induced by AAP consumption recommended in the clinical guidelines for schizophrenia and other psychiatric disorders.

Paliperidone, a relatively novel atypical antipsychotic drug, is a substrate for breast cancer resistance protein

Paliperidone (PAL) is a relatively novel atypical antipsychotic drug for schizophrenia that induces markedly varying responses. Breast cancer resistance protein (BCRP) is a recently discovered member of the ATP-binding cassette superfamily that has been used to control drug absorption, distribution and elimination, and especially to impede drug entry into the brain. To the best of our knowledge, the present study is the first to investigate the possibility of using PAL as a BCRP substrate. The intracellular accumulation and bidirectional transport were investigated using transfected 293 cell/BCRP and porcine renal endothelial cell (LLC-PK1)/BCRP cell monolayers and BCRP overexpression was confirmed by reverse transcription-quantitative polymerase chain reaction and western blot analysis. The in vitro affinity to BCRP was assessed in human BCRP (Arg482) membranes. The intracellular accumulation and bidirectional transport investigations demonstrated that BCRP can efflux PAL from cells and significantly decrease its cellular concentration over a concentration range of 0.1-50 µM. The in vitro affinity experiments indicated that PAL has a moderate affinity to BCRP at 0.1-100 µM. These results together suggest that PAL is a substrate for BCRP and that it can affect the blood-brain barrier penetration of PAL at therapeutic dosages.

Clinically significant drug interactions with atypical antipsychotics

Atypical antipsychotics [also known as second-generation antipsychotics (SGAs)] have become a mainstay therapeutic treatment intervention for patients with schizophrenia, bipolar disorders and other psychotic conditions. These agents are commonly used with other medications--most notably, antidepressants and antiepileptic drugs. Drug interactions can take place by various pharmacokinetic, pharmacodynamic and pharmaceutical mechanisms. The pharmacokinetic profile of each SGA, especially with phase I and phase II metabolism, can allow for potentially significant drug interactions. Pharmacodynamic interactions arise when agents have comparable receptor site activity, which can lead to additive or competitive effects without alterations in measured plasma drug concentrations. Additionally, the role of drug transporters in drug interactions continues to evolve and may effect both pharmacokinetic and pharmacodynamic interactions. Pharmaceutical interactions occur when physical incompatibilities take place between agents prior to drug absorption. Approximate therapeutic plasma concentration ranges have been suggested for a number of SGAs. Drug interactions that markedly increase or decrease the concentrations of these agents beyond their ranges can lead to adverse events or diminished clinical efficacy. Most clinically significant drug interactions with SGAs occur via the cytochrome P450 (CYP) system. Many but not all drug interactions with SGAs are identified during drug discovery and pre-clinical development by employing a series of standardized in vitro and in vivo studies with known CYP inducers and inhibitors. Later therapeutic drug monitoring programmes, clinical studies and case reports offer methods to identify additional clinically significant drug interactions. Some commonly co-administered drugs with a significant potential for drug-drug interactions with selected SGAs include some SSRIs. Antiepileptic mood stabilizers such as carbamazepine and valproate, as well as other antiepileptic drugs such as phenobarbital and phenytoin, may decrease plasma SGA concentrations. Some anti-infective agents such as protease inhibitors and fluoroquinolones are of concern as well. Two additional important factors that influence drug interactions with SGAs are dose and time dependence. Smoking is very common among psychiatric patients and can induce CYP1A2 enzymes, thereby lowering expected plasma levels of certain SGAs. It is recommended that ziprasidone and lurasidone are taken with food to promote drug absorption, otherwise their bioavailability can be reduced. Clinicians must be aware of the variety of factors that can increase the likelihood of clinically significant drug interactions with SGAs, and must carefully monitor patients to maximize treatment efficacy while minimizing adverse events.