A comparison of dissolving microneedles and transdermal film with solid microneedles for iloperidone in vivo: a proof of concept

Iloperidone (ILO) is a poorly soluble and bioavailable WHO-approved schizophrenia drug. Microneedles are a revolutionary delivery technology that overcomes many of the issues associated with traditional drug administration. The current research aimed to compare the antipsychotic activity and pharmacokinetics of ILO-loaded dissolving microneedles (DMNs) and transdermal film with a solid microneedle (STF). The DMNs were fabricated using the micromolding process, while the transdermal film was created using the solvent casting approach. Furthermore, an in vivo pharmacokinetic, pharmacodynamic, and skin irritation study was performed on Wistar rats. Studies were compared with transdermal film (TF) on untreated skin as a passive control. STF and DMNs had considerably greater AUC and C_max (p ≤ 0.001) than transdermal film. In pharmacodynamic tests, STF and DMNs demonstrated significant (p ≤ 0.001) forelimb retraction time (FRT) and hindlimb retraction time (HRT) delay responses as compared to control and TF. In the skin irritation test, no adverse effects such as erythema or edema were observed at the end of the 48 h. Thus, antipsychotic activity (paw test) and pharmacokinetics studies revealed sustained action of DMN and STF. This research revealed that improved efficacy of DMN and STF for antipsychotic drug delivery may be an alternative to the existing dosage form.

Optimization and characterization of self-nanoemulsifying drug delivery system of iloperidone using box-behnken design and desirability function

PURPOSE

Iloperidone (IP) is an antipsychotic drug which belongs to Biopharmaceutical Classification System (BCS) II exhibiting poor aqueous solubility. The current investigation explores the possibility of enhancement of solubility and dissolution characteristics of IP by formulation of liquid self-nano emulsifying drug delivery system (L-SNEDDS) utilizing Box-Behnken Design (BBD) and desirability function.

METHODS

The oils, surfactants and co-surfactants used in the study were selected based on solubility of the drug and their emulsification ability. Optimization of the formulation was performed using BBD by employing four response variables such as globule size (nm), percentage transmittance (%), self-emulsification time (sec) and percent drug released in 15min. 2D contour plots and 3D response surface plots were constructed using Design Expert software.

RESULTS

The developed optimal L-SNEDDS of IP through BBD approach resulted in improvement of solubility and dissolution rate as compared with the pure drug. Based on desirability function, optimized formulation was prepared and was assessed for response variables (globule size, percentage transmittance, self-emulsification time and percent drug dissolved in 15min). The characterization studies revealed droplet size to be 21.80±2.41nm, 99.584±0.65% transmittance, 24.43±2.12sec emulsification time and 95.31±1.57% cumulative drug release in 15min.

CONCLUSION

The results conclude the potentiality of prepared L-SNEDDS in improving solubility and dissolution rate of IP.

Pharmacokinetic and pharmacodynamic studies of iloperidone-loaded lipid nanoemulsions via oral route of administration

Iloperidone (IL) is practically insoluble in water and has significant first-pass metabolism, resulting in low oral bioavailability in humans (36%). IL lipid nanoemulsions (IL-LNEs) were prepared to improve oral bioavailability. IL-LNEs were formulated by hot homogenization and ultrasonication method. Soybean oil and egg lecithin in various concentrations as emulsifier were used in the preparation of LNEs. Dynamic light scattering technique was used for globule size analysis. All LNE formulations showed narrow size distribution and the average globule size and Poly Dispersity Index (PDI) were found to be in between 182.2 ± 2.8 to 222.3 ± 1.9 nm and 0.200 ± 0.004 to 0.274 ± 0.005 respectively. Zeta potential values varied from -20.0 ± 0.15 to -28.9 ± 0.30 mV which indicated stability of prepared LNEs. All formulations showed good entrapment efficiency ranging from 99.07 ± 0.01 to 99.28 ± 0.01% when separated using centrisart tubes and the drug content varied from 96.99 ± 0.94 to 99.06 ± 0.36%. Physical stability testing indicated the stability of all LNEs and optimized LNE-IL4 was found stable for 3 months at both refrigerated (4 °C) and room temperature (25 °C). During in vivo studies in wistar rats, the optimized LNE showed 2.47-fold improvement in the oral bioavailability and superior (1.22-fold) pharmacodynamic activity when compared to marketed tablet suspension (Ilosure-4^®) in suppressing the hyperlocomotor activity, being induced by MK-801 (Dizocilpine).

A significance for drug-drug interactions during combined therapy

Antipsychotics are often used in combination with other psychotropic drugs to treat a variety of psychiatric disorders, as well as in combination with other drugs taken by patients with co-morbidities. When these drugs are combined, the potential for drug-drug interaction increases, leading to side-effects, in addition to the predicted increase in effectiveness. The present study aimed at examining the effects of the three atypical neuroleptics asenapine, lurasidone and iloperidone on cytochrome P450 (CYP) expression in the human liver. The study was carried out on cryopreserved human hepatocytes. The hepatotoxicity of the tested drugs was assessed after exposure to the neuroleptics (LDH cytotoxicity assay). CYP activities were measured in the incubation medium using the CYP-specific reactions: caffeine 3-N-demethylation (CYP1A1/2), diclofenac 4'-hydroxylation (CYP2C9), perazine N-demethylation (CYP2C19) and testosterone 6β-hydroxylation (CYP3A4). Parallel, CYP mRNA levels were measured in neuroleptic-treated hepatocytes. Asenapine significantly decreased the mRNA level and activity of CYP1A2, while iloperidone potently diminished the mRNA level and activity of CYP3A4 in the cultures of human hepatocytes. Lurasidone did not affect the expression and activity of any of the investigated human CYP enzymes. The presented findings may have clinical implications for the prediction of potential drug-drug interactions involving the asenapine-induced inhibition of metabolism of CYP1A2 substrates (e.g. caffeine, theophylline, melatonin, tricyclic antidepressants, phenacetin, propranolol) and iloperidone-induced inhibition of CYP3A4 substrates (e.g. antidepressants, benzodiazepines, atorvastatin, macrolide antibiotics, calcium channel antagonists).

An update on the efficacy and safety of iloperidone as a schizophrenia therapy

INTRODUCTION

Schizophrenia has a prevalence of approximately 1% in the general population, with 15.2 per 100,000 persons affected. Iloperidone is a second-generation antipsychotic drug approved for the treatment of schizophrenia in adults. It acts primarily by D2/5HT2a receptor antagonism, with greater affinity for the 5HT2a receptor than for the D2 receptor.

AREAS COVERED

This article discusses iloperidone and aims to provide useful information for clinicians to determine which circumstances would best suit the use of iloperidone to treat schizophrenic patients. In this review, the authors briefly discuss schizophrenia and its treatment, before they discuss properties of iloperidone, its indications, approval process, and adverse effects. Finally, the authors review the specific strengths and weaknesses of the medication.

EXPERT OPINION

Iloperidone would be an attractive option in patients who are particularly prone to EPS, or who are showing prominent negative symptoms, as well as cognitive deficits. Its availability only in an oral formulation makes it a better option for patients with good medication adherence, and though it could be useful in patients prone to weight gain or hepatic dysfunction on other second generation antipsychotics, it should be used with caution in patients prone to side effects related to alpha adrenergic blockade.

Inhibition of voltage-dependent K+ channels by iloperidone in coronary arterial smooth muscle cells

Iloperidone, a second-generation atypical antipsychotic drug, is widely used in the treatment of schizophrenia. However, the side-effects of iloperidone on vascular K⁺ channels remain to be determined. Therefore, we explored the effect of iloperidone on voltage-dependent K⁺ (Kv) channels in rabbit coronary arterial smooth muscle cells using the whole-cell patch-clamp technique. Iloperidone inhibited vascular Kv channels in a concentration-dependent manner with a half-maximal inhibitory concentration (IC₅₀ ) of 2.11 ± 0.5 μM and a Hill coefficient of 0.68 ± 0.03. Iloperidone had no effect on the steady-state inactivation kinetics. However, it shifted the steady-state activation curve to the right, indicating that iloperidone inhibited Kv channels by influencing the voltage sensors. Application of 20 repetitive depolarizing pulses (1 and 2 Hz) progressively increased the inhibition of the Kv current in the presence of iloperidone. Furthermore, iloperidone increased the recovery time constant from Kv channel inactivation, suggesting that iloperidone-induced inhibition of Kv channels is use (state)-dependent. Pretreatment with a Kv1.5 inhibitor (diphenyl phosphine oxide 1 [DPO-1]) inhibited the Kv current to a level similar to that with iloperidone alone. However, pretreatment with a Kv2.1 or Kv7.X inhibitor (guangxitoxin or linopirdine) did not affect the inhibitory effect of iloperidone on Kv channels. Therefore, iloperidone directly inhibits Kv channels in a concentration- and use (state)-dependent manner independently of its antagonism of serotonin and dopamine receptors. Furthermore, the primary target of iloperidone is the Kv1.5 subtype.

Evaluation of potential metabolic interactions

Background

The present study aimed at examining the inhibitory effect of two atypical neuroleptics iloperidone and lurasidone on the main human cytochrome P450 (CYP) enzymes in pooled human liver microsomes and cDNA-expressed CYP enzymes (supersomes).

Methods

The activity of these enzymes was determined by the following CYP-specific reactions: caffeine 3-N-demethylation/CYP1A2, diclofenac 4′-hydroxylation/CYP2C9, perazine N-demethylation/CYP2C19, bufuralol 1′-hydroxylation/CYP2D6 and testosterone 6β-hydroxylation/CYP3A4, respectively, using HPLC.

Results

Iloperidone inhibited the activity of CYP3A4 via a noncompetitive mechanism (K_i = 0.38 and 0.3 µM in liver microsomes and supersomes, respectively) and CYP2D6 via a competitive mechanism (K_i = 2.9 and 10 µM in microsomes and supersomes). Moreover, iloperidone attenuated the activity of CYP1A2 (K_i = 45 and 31 µM in microsomes and supersomes) and CYP2C19 via a mixed mechanism (K_i = 6.5 and 32 µM in microsomes and supersomes) but did not affect CYP2C9. Lurasidone moderately inhibited CYP1A2 (K_i = 12.6 and 15.5 µM in microsomes and supersomes), CYP2C9 (K_i = 18 and 3.5 µM in microsomes and supersomes) and CYP2C19 via a mixed mechanism (K_i = 18 and 18.4 µM in microsomes and supersomes), and CYP3A4 via a competitive mechanism (K_i = 29.4 and 9.1 µM in microsomes and supersomes). Moreover, lurasidone competitively, though weakly diminished the CYP2D6 activity (K_i = 37.5 and 85 µM in microsomes and supersomes).

Conclusion

The examined neuroleptics showed inhibitory effects on different CYP enzymes. The obtained results indicate that metabolic/pharmacokinetic interactions with iloperidone (involving mainly CYP3A4 and CYP2D6) and possibly with lurasidone (involving CYP1A2, CYP2C9 or CYP2C19) may occur during combined therapy.

Repurposing of Iloperidone: Antihypertensive and ocular hypotensive activity in animals

PURPOSE

Iloperidone, second generation antipsychotic drug, reported in clinical trial to produce orthostatic hypotension as side effect. It was claimed to be antagonistic at alpha adrenergic receptor in central nervous system. We evaluated effect of Iloperidone on peripheral alpha 1 adrenoreceptor by in silico and in vitro methods while in vivo hypotensive, antihypertensive and ocular hypotensive activity was evaluated in animals.

METHODS

Pharmacological activity prediction of Iloperidone was done using PASSOnline and SwissTargetPrediction softwares and molecular docking with Alpha 1A adrenoreceptor using AutoDock Vina. Hypotensive activity in normotensive and antihypertensive activity against DOCA-salt induced hypertension in rats were evaluated at doses 0.03 mg/Kg and 0.1 mg/Kg, i.p of Iloperidone. Blood pressure was measured by invasive blood pressure measurement technique using PowerLab 4/30 and intraocular pressure was measured using digital tonometer.

RESULTS

Iloperidone (0.1 mg/Kg) showed significant decrease in blood pressure (38.96 ± 1.1%) in normotensive rats, while in DOCA salt induced hypertensive rats, systolic blood pressure was found to be decreased by 29.04 ± 1.45% and 31.43 ± 1.21% in 0.03 mg/Kg and 0.1 mg/Kg treated rats respectively. Iloperidone prevented rise in systolic BP with adrenaline. Intraocular pressure was found to be decreased by 36.66 ± 3.15% in rabbits after 1 h of instillation of 0.1% Iloperidone.

CONCLUSION

Iloperidone exerted hypotensive and/or anti-hypertensive activity in rats and ocular hypotensive activity in rabbits.

A case of iloperidone overdose in a 27-year-old man with cocaine abuse

Introduction:

Iloperidone is a recently introduced antipsychotic medication. It is approved for the treatment of schizophrenia. There are no published reports of iloperidone overdosage, but there are eight cases that have been reported to the US Food and Drug Administration.

Case report:

A case of a 27-year-old man who took 84 mg of iloperidone while also smoking cocaine is described. He developed a prolonged QTc (527 ms) without arrhythmias and respiratory failure with mandated respiratory support. He ultimately recovered without sequelae.

Discussion:

The information regarding previous cases of toxicity on the US Food and Drug Administration website is incomplete. However, there were no fatalities due to iloperidone over-ingestion. Prolongation of the QTc may be a common feature.

Trends in the use of antipsychotics in the Israeli inpatient population, 2004-2013

Background

Although serious mental illneses are treated with both typical and atypical antipsychotic grugs, trends in their use in psychiatric inpatient population in Israel are unrecognized. The aim of this study was to detect trends in the use of typical and atypical antipsychotic drugs in the Israeli inpatient psychiatric population throughout the last decade.

Methods

Data regarding allocation of typical and atypical antipsychotics, over the period 2004 to 2013, were extracted from the electronic records of SAREL, Israel’s largest private supplier of drugs to healthcare and medical facilities. The data were converted to defined daily doses (DDD) per 1000 inpatients per day.

Results

Usage of the ten atypical antipsychotic agents allocated through Israel’s national health care system increased by 73 %, from 128.09 DDD/1000 inpatients/day in 2004 to 221.69 DDD/1000 inpatients/day in 2013. This rise from 2004 to 2013 was largely due to a 1.6-fold increase in the administration of olanzapine (48.31 to 79.57 DDD/1000 inpatients/day), a 4.4-fold increase of quetiapine (9.74 to 43.04 DDD/1000 inpatients/day) and 3.7-fold increase of amisulpride (5.54 to 20.38 DDD/1000 inpatients/day). At the same period, the total utilization of 12 main typical antipsychotics decreased by 15.5 %, from 148.67 DDD/1000 inpatients/day in 2004 to 125.57 DDD/1000 inpatients/day in 2013. Over the entire period, total DDDs of both classes of antipsychotics (typical and atypical) increased by 38 %.

Conclusions

Similar to trends in the treatment of psychiatric outpatients in other countries, there was a substantial increase in the administration of atypical antipsychotic drugs to the Israeli psychiatric inpatient population across the study period. A decrease in the use of typical antipsychotics (substitution), polypharmacy, administration for more indications (supplementation) and the use of larger doses of antipsychotics may account, in part, for this increase. The findings have implications for mental health policy in the context of the Mental Health Care System Reform. Systematic studies on appropriate dosing of antipsychotics and augmentation strategies are warranted.

Switching to iloperidone: An omnibus of clinically relevant observations from a 12-week, open-label, randomized clinical trial in 500 persons with schizophrenia

OBJECTIVE

To describe secondary analyses from a 12-week, randomized, open-label trial where adult schizophrenia outpatients receiving risperidone, olanzapine, or aripiprazole were switched to iloperidone.

METHODS

Patients were randomized into two groups: one where the antecedent antipsychotic dose was titrated downwards to zero over 2 weeks (n=240), and the other group where the antecedent antipsychotic was abruptly stopped (n=260). Adaptations of the Clinical Global Impression scale were used to evaluate clinical changes. Other assessments included the reporting of adverse events (AEs), study discontinuation, body weight, and metabolic variables.

RESULTS

Improvement was steady throughout the study for both gradual- and immediate-switch groups starting at Week 1 and continuing through Week 12. Discontinuations due to AEs in the first 2 weeks of treatment were higher for the immediate-switch group compared with the gradual-switch group (10.8% vs. 5.4%, NNT 19, 95% CI 10-151). Fewer patients in the gradual-switch group experienced dizziness as an AE, whereas a higher percentage of patients in the immediate-switch group exhibited earlier onset of a therapeutic response within the first 2 weeks; both groups were comparable thereafter with low rates of dizziness and similar efficacy outcomes.

CONCLUSIONS

Switching to iloperidone can be accomplished either with a gradual crossover or immediate discontinuation of the prior antipsychotic; however, the immediate-switch method is associated with greater proportion of initial dizziness. The observed outcomes are consistent with what has been previously reported regarding iloperidone's favorable akathisia/EPS profile and modest impact on somnolence/sedation, body weight, and metabolic variables.

Priapism associated with iloperidone: a case report

Priapism is a known side effect of antipsychotics. The causal mechanism seems to be mediated through α1-adrenergic receptor blockade which many antipsychotics are known to possess. We present the first detailed case of iloperidone-induced priapism in a patient with bipolar disorder with psychotic features. His case highlights some of the important risk factors clinicians should consider when using iloperidone, as it may be the highest-risk antipsychotic for causing priapism given it is a very potent blocker of the alpha-adrenergic receptor.

A trial evaluating gradual- or immediate-switch strategies from risperidone, olanzapine, or aripiprazole to iloperidone in patients with schizophrenia

In a 12-week randomized open-label trial, adults diagnosed with schizophrenia experiencing inadequate efficacy and/or poor tolerability on risperidone, olanzapine, or aripiprazole were randomized to switch to iloperidone either gradually (ie, down-titration of current therapy over the first 2weeks [to 50% on Day 1, 25% by Week 1, 0% by Week 2]) or immediately. All patients were titrated on iloperidone to 6mg BID by Day 4, then flexibly dosing between 6 and 12mg BID, as needed. The primary variable was the Integrated Clinical Global Impression of Change (I-CGI-C) and the primary analysis time point was Week 12. A total of 500 patients were randomized and received iloperidone (gradual switch, 240; immediate switch, 260), with 175, 155, and 170 patients switched from risperidone, olanzapine, and aripiprazole, respectively. I-CGI-C Results confirmed improved outcomes at Week 12, with scores that were similar between the gradual- and immediate-switch groups, respectively, for risperidone, 2.82 and 2.67 (95% CI: -0.229, 0.511); olanzapine, 2.87 and 3.03 (95% CI: -0.548, 0.235); and aripiprazole, 2.79 and 2.81 (95% CI: -0.405, 0.368). Incidence of adverse events (AEs) was similar in both switch groups, with the most frequently reported (≥10%) being dizziness, dry mouth, somnolence, and weight increase. In conclusion, switching to iloperidone by either a gradual or an immediate method did not reveal any clinically significant differences in ratings of overall efficacy and safety/tolerability outcomes, based on the I-CGI-C at 12weeks. Similar overall safety/AE profiles were observed regardless of the specific agent from which patients were switched.