Study of the complexation of risperidone and 9-hydroxyrisperidone with cyclodextrin hosts using affinity capillary electrophoresis and 1H NMR spectroscopy

Designed proteinoid polymers and nanoparticles encapsulating risperidone for enhanced antipsychotic activity

BACKGROUND

Nanoparticles (NPs) incorporating drug formulations can be used to facilitate passage through biological barriers including the blood-brain barrier (BBB) and increase drug delivery and bioavailability. Hence, NP-based administration may enhance the efficiency of current antipsychotics. Encapsulation within NPs can resolve aqueous solubility problems that not only reduce permeability through the BBB but also affect targeting. The present study describes a new drug delivery system based on proteinoid NPs to explore the possibility of improving drug efficacy. Risperidone (RSP) is a commonly used atypical antipsychotic medication, and was therefore selected for encapsulation by proteinoid NPs.

RESULTS

Proteinoid polymers with high molecular weight and low polydispersity were synthesized from L-amino acids and poly-L-lactic acid (PLLA) by thermal step-growth polymerization mechanism. RSP-loaded proteinoid NPs were then prepared using a self-assembly process in the presence of RSP, followed by PEGylation. The optimal PEGylated RSP-loaded NPs were characterized in terms of diameter and size distribution, drug loading, ζ-potential, cytotoxicity, biodistribution, and psychopharmacological effects. The findings indicate significantly higher antipsychotic activity of drug-loaded proteinoid NPs compared to free RSP.

CONCLUSIONS

Proteinoid NPs enhance RSP delivery and may potentially increase drug efficiency by reducing dosage and side effects.

Development and Evaluation of pH-Responsive Cyclodextrin-Based in situ Gel of Paliperidone for Intranasal Delivery

Paliperidone (PLPD) is approved for treatment and management of schizophrenia. The current study demonstrates the potential of in situ gel of PLPD for nasal delivery. The permeation of drug through sheep nasal mucosa was analyzed since the nose-to-brain pathway has been indicated for delivering drugs to the brain. The carbopol 934 (CP)- and hydroxypropyl methyl cellulose K4M (HPMC)-based in situ gels containing 0.2% CP and 0.4% w/v HPMC were optimized using experimental design software. The use of hydroxypropyl-β-cyclodextrin (HP-β-CD) in nasal permeation of drug was investigated. Transmucosal permeation of PLPD was examined using sheep nasal mucosa. The in situ gels of PLPD exhibited satisfactory mucoadhesion and showed sustained drug release. The mucocilliary toxicity and histopathological examination confirmed that the nasal mucosa architecture remains unaffected after treatment with PLPD in situ gel. The formulation containing HP-β-CD complex of PLPD exhibited higher rate of drug permeation through sheep nasal mucosa revealing the role of HP-β-CD as nasal absorption enhancer. Thus, CP- and HPMC-based pH-triggered in situ gel containing HP-β-CD-drug inclusion complex demonstrates a novel nasal delivery of PLPD.

Evaluation of three neutral capillary coatings for the determination of analyte-cyclodextrin binding constants by affinity capillary electrophoresis. Application to N,N'-disubstituted piperazine derivatives

The performances of three neutral static coatings (hydroxypropyl cellulose, polyethylene oxide and poly(N,N-dimethylacrylamide) have been evaluated in order to determine the binding constants of the complexes formed between four polycationic compounds (piperazine derivatives) and four cyclodextrins of pharmaceutical interest (β-CD, HP-β-CD, Me-β-CD and sulfobutyl ether-β-CD) by affinity capillary electrophoresis. The physically-adsorbed poly(N,N-dimethylacrylamide) coating proves to be the more efficient to mask the silanol groups of the capillary wall since the lowest electroosmotic flow was measured for this coating. Moreover, it drastically reduces the adsorption of the compounds since it allows a correct repeatability of their migration time, higher efficiencies of the peaks and no baseline shift. Then, it was verified for four complexes that this coating allows a correct determination of the binding constants avoiding the CD adsorption which is responsible of an undervaluation of binding constants. The highest binding constants are obtained using the anionic sulfobutyl ether-β-CD (SBE-β-CD). The structure of the complex formed between the tacrine derivative and the SBE-β-CD was further investigated through 2D ROESY NMR experiments and structure-binding constant relationships. Results suggest that the inclusion in the SBE-β-CD cavity occurs through the aliphatic ring portion of the tacrine moiety.

Recent advances in affinity capillary electrophoresis for binding studies

The present review covers recent advances and important applications of affinity capillary electrophoresis (ACE). It provides an overview about various ACE types, including ACE-MS, the multiple injection mode, the use of microchips and field-amplified sample injection-ACE. The most common scenarios of the studied affinity interactions are protein-drug, protein-metal ion, protein-protein, protein-DNA, protein-carbohydrate, carbohydrate-drug, peptide-peptide, DNA-drug and antigen-antibody. Approaches for the improvements of ACE in term of precision, rinsing protocols and sensitivity are discussed. The combined use of computer simulation programs to support data evaluation is presented. In conclusion, the performance of ACE is compared with other techniques such as equilibrium dialysis, parallel artificial membrane permeability assay, high-performance affinity chromatography as well as surface plasmon resonance, ultraviolet, circular dichroism, nuclear magnetic resonance, Fourier transform infrared, fluorescence, MS and isothermal titration calorimetry.

A new sensing platform based on electrospun copper oxide/ionic liquid nanocomposite for selective determination of risperidone

A copper oxide nanoparticle/ionic liquid nanocomposite modified electrode exhibits excellent electrocatalytic activity towards the oxidation of risperidone.

Near infrared spectroscopic (NIRS) analysis of drug-loading rate and particle size of risperidone microspheres by improved chemometric model

Microspheres have been developed as drug carriers in controlled drug delivery systems for years. In our present study, near infrared spectroscopy (NIRS) is applied to analyze the particle size and drug loading rate in risperidone poly(d,l-lactide-co-glycolide) (PLGA) microspheres. Various batches of risperidone PLGA microspheres were designed and prepared successfully. The particle size and drug-loading rate of all the samples were determined by a laser diffraction particle size analyzer and high performance liquid chromatography (HPLC) system. Monte Carlo algorithm combined with partial least squares (MCPLS) method was applied to identify the outliers and choose the numbers of calibration set. Furthermore, a series of preprocessing methods were performed to remove signal noise in NIR spectra. Moving window PLS and radical basis function neural network (RBFNN) methods were employed to establish calibration model. Our data demonstrated that PLS-developed model was only suitable for drug loading analysis in risperidone PLGA microspheres. Comparatively, RBFNN-based predictive models possess better fitting quality, predictive effect, and stability for both drug loading rate and particle size analysis. The correlation coefficients of calibration set (Rc(2)) were 0.935 and 0.880, respectively. The performance of optimum RBFNN models was confirmed by independent verification test with 15 samples. Collectively, our method is successfully performed to monitor drug-loading rate and particle size during risperidone PLGA microspheres preparation.

Study on the luminescence behavior of sulfobutylether-β-cyclodextrin with risperidone and its analytical application

The interaction of sulfobutylether-β-cyclodextrin (SBE-β-CD) with risperidone (RISP) was first described with luminol-SBE-β-CD chemiluminescence (CL) system by flow injection analysis (FIA). In luminol-SBE-β-CD CL system, the 1:1 SBE-β-CD···luminol(*) complexation could enhance CL intensity of luminol and produce the effect of complexation enhancement of CL (CEC). It was found that RISP could quench the CL intensity of SBE-β-CD···luminol(*) and caused the effect of complexation enhancement of quenching (CEQ), the formation constant K(R-CD) 3.4×10(4) L mol(-1) and the stoichiometric ratio 1:1 of RISP···SBE-β-CD complex were obtained by the proposed CL model. Association degree α 0.036 of RISP···SBE-β-CD complex was also given by CL method. Based on the linear relationship to the decrement of luminol-SBE-β-CD-RISP CL intensity and the logarithm of RISP concentration, RISP also can be quantified in the linear range of 3.0-500.0 nmol L(-1) with a detection limit of 1.0 nmol L(-1) (3σ). The proposed method was successfully applied to monitoring excreted RISP in human urine. It was found that RISP reached its maximum after oral administration for 1.5 h with the total excretion of 14.26% within 8.5 h; the elimination rate constant k and half-life time t(1/2) were 0.474 and 1.5 h, respectively.

Assessment of chemokine profiles in human skin biopsies by an immunoaffinity capillary electrophoresis chip

Atopic dermatitis is a skin condition resulting in a skin rash from exposure to environmental factors. Skin biopsies taken from patients suffering from atopic dermatitis were micro-dissected and analyzed using a microchip-based immunoaffinity CE system for the presence of CXCL1, CXCL5 and CXCL8 and CCL1, CCL3 and CCL5 chemokines. Disposable immunoaffinity disks with immobilized antibodies were used to capture the CXC and CC chemokines from the homogenized skin samples. The captured analytes were then labeled with AlexaFluor 633, eluted from the disk and separated by CE. The labeled chemokines were identified and quantified by laser induced fluorescence. The total analysis time was less than 40min, including the biopsy microdissection, pre-analysis preparation of the sample and the ICE-CHIP analysis, which took less than 10min with inter- and intra-assay CV's below 6.4%. Microchip-based immunoaffinity CE could distinguish between normal skin biopsies and those with inflammation. Patients with neutrophil cellular infiltrates by histopathology showed increased concentrations of CXCL1, CXCL5 and CXCL8 while increases of CCL1, CCL3 and CCL5 corresponded to the patient group demonstrating monocytic and T-lymphocyte infiltration by histopathology. This system demonstrates the ability to identify and quantify immunochemical analytes in frozen sections taken from clinical histopathology samples.

Stability indicating HPLC determination of risperidone in bulk drug and pharmaceutical formulations

The objective of the current study was to develop a validated stability-indicating assay method (SIAM) for risperidone after subjecting it to forced decomposition under hydrolysis, oxidation, photolysis, and thermal stress conditions. The liquid chromatographic separation was achieved isocratically on a symmetry C18 column (5 μm size, 250 mm × 4.6 mm i.d.) using a mobile phase containing methanol: acetonitrile (80 : 20, v/v) at a flow rate of 1 mL/min and UV detection at 280 nm. Retention time of risperidone was found to be 3.35 ± 0.01. The method was linear over the concentration range of 10-60 μg/mL(r(2) = 0.998) with a limit of detection and quantitation of 1.79 and 5.44 μg/mL, respectively. The method has the requisite accuracy, specificity, sensitivity, and precision to assay risperidone in bulk form and pharmaceutical dosage forms. Degradation products resulting from the stress studies did not interfere with the detection of Risperidone, and the assay is thus stability indicating.

Risperidone solid dispersion for orally disintegrating tablet: its formulation design and non-destructive methods of evaluation

The focus of present investigation was to assess the utility of non-destructive techniques in the evaluation of risperidone solid dispersions (SD) with methyl-β-cyclodextrin (MBCD) and subsequent incorporation of the SD into orally disintegrating tablets (ODT) for a faster release of risperidone. The SD was prepared by a solvent evaporation method and evaluated by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), near infrared spectroscopy (NIR), NIR-chemical imaging (NIR-CI), powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC). DSC and XRD analysis indicated that crystallinity of SD has reduced significantly. FTIR showed no interaction between risperidone and MBCD. Partial least square (PLS) was applied to the NIR data for the construction of chemometric models to determine both components of the SD. Good correlations were obtained for calibration and prediction as indicated by correlation coefficients >0.9965. The model was more accurate and less biased in predicting the MBCD than risperidone as indicated by its lower mean accuracy and mean bias values. SD-3 (risperidone:MBCD, 1:3) was incorporated into ODT tablets containing diluent (D-mannitol, FlowLac(®) 100 or galenIQ™-721) and superdisintegrant (Kollidon(®) CL-SF, Ac-Di-Sol or sodium starch glycolate). Disintegration time, T(50) and T(90) were decreased in the formulations containing mannitol and Kollidon(®) CL-SF, but increased with galenIQ™-721 and sodium starch glycolate, respectively. NIR-CI images confirmed the homogeneity of SD and ODT formulations.

Chip-based immunoaffinity CE: application to the measurement of brain-derived neurotrophic factor in skin biopsies

A chip-based immunoaffinity CE system has been employed to measure the concentrations of brain-derived neurotrophic factor in human skin biopsies, taken during atopic inflammatory events. The device employs a replaceable immunoaffinity disk to which capture antibodies have been chemically immobilized. Homogenates obtained from micro-dissected human skin samples were injected into the system, where the analyte of interest was captured in the immunoextraction port, thus allowing non-reactive materials to be removed prior to analysis. The captured analyte was labeled in situ with a red-emitting laser dye before being released from the capture antibody, separated by electrophoresis, and the resolved peaks detected by online LIF. Comparison of this chip-based system with conventional immunoassay demonstrated good correlation when analyzing both standards and patient samples. The system was semi-automated resulting in a CE analysis within 1.5 min and a total of circa 5 min. Intra- and inter-assay CV's of 3.85 and 4.19 were achieved with circa 98.8% recovery of brain-derived neurotrophic factor at a concentration of 100 pg/mL. The assay demonstrated clear differences between clinical stages of atopic dermatitis in human patients and could run 10-15 samples per hour. This system holds the potential for being modified to be a portable unit that could be used in clinics and other biomedical screening studies.

Paliperidone for schizophrenia

BACKGROUND

Paliperidone, risperidone's active metabolite, is now available in an oral formulation for daily use, and an intramuscular formulation for monthly administration may follow shortly.

OBJECTIVES

To compare effects of oral paliperidone with any other treatment for people with schizophrenia and schizophrenia-like illnesses.

SEARCH STRATEGY

We searched the Cochrane Schizophrenia Group's Register (December 2006), and inspected references of identified studies for further trials. We contacted the manufacturers of paliperidone, the Food and Drug Administration, and authors of relevant trials for additional material.

SELECTION CRITERIA

We included all relevant randomised trials.

DATA COLLECTION AND ANALYSIS

We independently selected and critically appraised studies, extracted data and analysed on an intention-to-treat basis. Where possible and appropriate, we calculated risk ratios (RR) and their 95% confidence intervals (CI) with the number needed to treat (NNT). We calculated Weighted Mean Differences (WMD) for continuous data.

MAIN RESULTS

Five studies compared paliperidone with placebo. Fewer people left the studies early if they were randomized to paliperidone (n=1647, 5 RCTs, RR 0.68 CI 0.61 to 0.76, NNT 7 CI 6 to 9) and those receiving any dose of paliperidone were significantly more likely to have an improvement in global state (n=1420, 4RCTs, RR 0.69 CI 0.63 to 0.75, NNT 5 CI 4 to 6). People randomised to paliperidone were less likely to experience a recurrence of psychosis (n=1638, 5 RCTs, RR 0.45 CI 0.31 to 0.66, NNT 16 CI 13 to 26) than those allocated to placebo. Adverse effect data were not well reported but paliperidone does seem to produce a greater incidence of tachycardia than placebo (n=1638, 5 RCTs, RR1.88 CI 1.28 to 2.76, NNH 21 CI 11 to 90) and a consistent, significant elevation in serum prolactin was found for both men (n=413, 3 RCTs, WMD 27.68 CI 23.66 to 31.69) and women (n=252, 3 RCTs, WMD 87.39 CI 74.27 to 100.51). People receiving paliperidone were more likely to experience extrapyramidal disorders (n=1638, 5 RCTs, RR 2.21 CI 1.26 to 3.88, NNH 28 CI 12 to 129) and weight gain (n=769, 4 RCTs, WMD 1.07 CI 0.65 to 1.49, I-squared 78%) compared with those allocated to placebo. When compared with 10 mg/day olanzapine we found no differences between paliperidone and olanzapine for leaving in the short term (n=1332, 3 RCTs, RR 1.04 CI 0.89 to 1.21; 40% in both groups left by six weeks). Those receiving any dose of paliperidone were no more likely to have a recurrence of psychotic symptoms than those receiving 10 mg/day olanzapine (n=1327, 3 RCTs, RR 0.1.07 CI 0.64 to 1.76). Data from all three studies found paliperidone was less likely to produce a weight change than olanzapine (n=660, 3 RCTs, WMD -0.88 CI -1.38 to -0.37). Results for various movement disorders all favoured olanzapine. There are no clear data relating to social functioning, services use, quality of life, satisfaction and cost.

AUTHORS' CONCLUSIONS

In short-term studies, oral paliperidone is an antipsychotic that is more efficacious than placebo. We found its adverse effects to be similar to those of its parent compound, risperidone, with movement disorders, weight gain, and tachycardia all more common with paliperidone than placebo. In addition, paliperidone is associated with substantial increases in serum prolactin that may be associated with sexual dysfunction, although sexual functioning outcomes were not reported. At doses greater than 3 mg per day, oral paliperidone appears comparable in efficacy to oral olanzapine 10 mg per day. Regarding the critical comparison of oral paliperidone to risperidone, we have no information and are thus unable to determine if paliperidone has any advantages or disadvantages compared to its well-known parent compound.