Converting oral to long-acting injectable antipsychotics: a guide for the perplexed

Novel pH-Responsive Structural Rearrangement of Myristic Acid-Conjugated Quetiapine Nanosuspension for Enhanced Long-Acting Delivery Performance

Quetiapine myristate (QM), an ester-bonded lipophilic prodrug of quetiapine (QTP), is synthesized and converted into an amphiphilic structure in acidic pH to trigger a novel self-assembled QM nanosuspension (QMN). Following injection, this QMN rearranges within physiological pH to form nanoaggregates in structure, resulting in enhanced physicochemical properties and in vivo therapeutic performance without an initial burst release. The 200-nm-sized QMN exhibits less invasive injection, higher drug content, and better storage stability profile than conventional poly(lactide-co-glycolide) (PLGA) nanosuspensions containing QTP or QM. Following a single intramuscular injection to beagle dogs (35 mg kg-1 QTP), QMN undergoes pH-responsive nanoaggregation to form the lipophilic prodrug, providing esterase-oriented sustained release for five weeks compared with the two-week period of PLGA nanosuspensions. Notably, QMN exhibits improved in vivo pharmacokinetic performance with long-acting delivery while minimizing issues associated with polymeric PLGA formulations, including the initial massive burst release, cellular toxicity, and adverse side effects. These results support the further development of QMN as a novel long-acting injectable to improve patient compliance and dosing frequency.

Roles of Fatty Acid Chain Length and Enzyme-Oriented Drug Controlled Release from pH-Triggering Self-Assembled Fatty Acid Conjugated Quetiapine Nanosuspensions

Background

Quetiapine (QTP) is a first-line antipsychotic drug, but its therapeutic druggability and patient adherence were limited due to high oral dose strength, low bioavailability and physicochemical/biopharmaceutical issues.

Purpose

To investigate the roles of fatty acid chain length and enzyme-oriented QTP controlled release from pH-triggering self-assembled fatty acid conjugated QTP nanosuspensions (NSPs).

Methods

QTP was conjugated with different chain length fatty acids (C10-decanoic acid, C14-myristic acid, C18-stearic acid) to obtain QTP-fatty acid conjugates (QFCs: QD, QM, QS) by exploiting 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/4-dimethylaminopyridine (EDC/DMAP) conjugation chemistry. Then, the solubility, partitioning coefficient (log P), cell viability and cleavage kinetics of QFCs were evaluated. The pH-triggering self-assembled behaviors of QFCs to form QTP-fatty acid NSPs (QDN, QMN, QSN) by varying pH, QFC concentration and proton-to-QTP ratios were characterized. The morphological images, critical micelle concentration (CMC), physicochemical properties and enzyme-oriented QTP controlled release of NSPs were examined.

Results

Three QFCs were synthesized with different chain length fatty acids from QTP after desalting fumarate from QTP fumarate. The pH, QFC concentration and proton-to-quetiapine molar ratio could influence physicochemical properties and nanonization behaviors of QFCs. All three QFCs showed no effect on the viability of myoblast cells. The pH-triggering self-assembly of amphiphilic QFCs to form nanoparticles (NPs) occurred as the amine moiety of QTP was readily ionized in a strongly acidic environment (pH 1.2). Interestingly, the longer the fatty acid chain length, the lower water solubility, the higher log P (lipophilicity) and the smaller NP particle size were observed. The conversion rate of QFCs to liberate QTP by esterase in human plasma and liver S9 fractions was also inversely proportional to the fatty acid carbon chain length. Interestingly, the freeze-dried QMN showed the esterase-oriented controlled release of QTP over one month, unlike the initial burst release of QDN or the slowly delayed release pattern of QSN.

Conclusion

A new pH-triggering self-assembled nanonization platform was developed using different chain length fatty acid conjugated QTP in low pH environment. By varying fatty acid chain length, the enzyme-oriented QTP controlled release dosage form was challenged to enhance the therapeutic effectiveness of QTP.

Switching to long-acting injectable antipsychotics: pharmacological considerations and practical approaches

INTRODUCTION

Long-acting injectable antipsychotics (LAIs) are an effective, but potentially underutilized treatment option in schizophrenia and other severe mental illnesses. Prescribing information typically focuses on how to initiate treatment from the corresponding oral formulations. However, in clinical practice other scenarios, such as switching from other oral antipsychotics or other LAIs, occur frequently, requiring guidance.

AREAS COVERED

Pharmacodynamic properties of antipsychotics and their relation to rebound symptoms. Pharmacokinetic properties of LAIs and their implications for switching approaches. Specific approaches to switching to LAIs.

EXPERT OPINION

The LAI landscape has evolved significantly in the last decade with more formulations available, longer dosing intervals, and extended indications. However, currently available LAIs have various shortcomings, e.g. short dosing intervals, need for oral supplementation, loading regimens, deep intramuscular injection and/or restricted indications. Recent improvements include a one-day initiation option for aripiprazole lauroxil, aripiprazole monohydrate once-monthly, risperidone in situ microparticles and subcutaneous risperidone. Future LAI developments should focus on longer dosing intervals, subcutaneous administration, expansion of LAIs beyond currently available antipsychotic agents and indications beyond schizophrenia and bipolar disorder. In the future, LAIs might become a first-line treatment after initial oral stabilization for chronic mental disorders with need for maintenance treatment and presence of significant non-adherence.

Aripiprazole Lauroxil Dosing Regimens: Understanding Dosage Strengths and Injection Intervals

Aripiprazole lauroxil (AL) is a long-acting atypical antipsychotic approved for the treatment of schizophrenia in adults. AL has five regimen options that offer three different injection intervals using four different dosage strengths. The relationship between dosage strength (milligram injected), injection interval (time between injection visits), and expected steady-state plasma aripiprazole concentrations may not be readily apparent. This article illustrates the relationship by providing visual scenarios of steady-state plasma aripiprazole concentrations for the five AL regimens. The efficacy of AL was originally demonstrated in a pivotal study of two AL regimens (approved as 441 mg monthly and 882 mg monthly). The three additional regimens (662 mg monthly, 882 mg every 6 weeks, and 1064 mg every 2 months) were approved based on pharmacokinetic bridging studies and population pharmacokinetic models. For this paper, expected steady-state concentrations for each AL regimen were derived from the published population pharmacokinetic models and compared using median values and ranges. The five labeled AL regimens differ in dosage strength and injection interval; however, model-simulated concentrations illustrate that each regimen produces steady-state plasma aripiprazole concentrations within the upper and lower bounds associated with known efficacy for AL 441 mg and 882 mg administered monthly. This visual presentation of the relationship between dosage strength of the AL injection, the interval between successive injections, and steady-state aripiprazole plasma concentrations may demonstrate for clinicians how dosage strength and injection interval can be considered in selecting the AL regimen option that best fits the clinical circumstances of the individual patient.

Attitudes and Willingness to Accept Long-Acting Injections for Patients With Schizophrenia in Beijing: A Cross-Sectional Investigation Based on Samples From the Communities

Background: Schizophrenia has brought a serious disease burden to China. Under the background that community rehabilitation has become the mainstream treatment model, the long-acting injection (LAI) can better prevent recurrence. Some districts in Beijing have also issued policies. This article aims to find out patient's current attitudes toward LAI and provide policy suggestions.

Methods: Some patients with schizophrenia in the communities are selected, while the survey format is face-to-face conversation. The content of the self-made questionnaire includes patients' willingness and reasons for accepting LAI treatment. Descriptive statistics, t-test and F-test are used to process the data from questionnaire surveys.

Results: About 10% of respondents have had experience using LAI and the current utilization rate is 2.4%. Respondents' willingness to accept LAI is generally low (only 18.1% are willing). The main reason for willingness is no need to take medication every day, while the main reasons for unwillingness are high cost, fear of injection and lack of understanding.

Conclusion: Beijing community patients are not very optimistic about LAI's cognition and willingness. Medication habits play an important role in their medication selection decisions. Intervention such as educate clinicians and patients about LAI and provide free injections to patients can be imposed. The promotion of LAI still has a long way to go.

Long-Acting Injectable Antipsychotics in the Treatment of Schizophrenia: Practical Considerations

The positive symptoms of schizophrenia are usually treated with oral antipsychotics despite high rates of nonadherence leading to relapse and rehospitalization. Seven long-acting injectable (LAI) antipsychotics are currently approved by the U.S. Food and Drug Administration for maintenance treatment of schizophrenia. These medications reduce the risk for nonadherence and relapse, yet relatively few clinicians prescribe them. All LAI anti-psychotics are equally effective in treating the positive symptoms of schizophrenia. Dosing requirements, dosing frequencies, and what clinicians should consider in choosing a LAI antipsychotic for a specific patient are discussed. Communication strategies that help patients and families understand what they need to know about schizophrenia and its treatment to share in the decision-making process are also provided. [Journal of Psychosocial Nursing and Mental Health Services, 59(7), 7-12.].

Poly(l-Lactic Acid)-co-poly(Butylene Adipate) New Block Copolymers for the Preparation of Drug-Loaded Long Acting Injectable Microparticles

The present study evaluates the use of newly synthesized poly(l-lactic acid)-co-poly(butylene adipate) (PLA/PBAd) block copolymers as microcarriers for the preparation of aripiprazole (ARI)-loaded long acting injectable (LAI) formulations. The effect of various PLA to PBAd ratios (95/5, 90/10, 75/25 and 50/50 w/w) on the enzymatic hydrolysis of the copolymers showed increasing erosion rates by increasing the PBAd content, while cytotoxicity studies revealed non-toxicity for all prepared biomaterials. SEM images showed the formation of well-shaped, spherical MPs with a smooth exterior surface and no particle's agglomeration, while DSC and pXRD data revealed that the presence of PBAd in the copolymers favors the amorphization of ARI. FTIR spectroscopy showed the formation of new ester bonds between the PLA and PBAd parts, while analysis of the MP formulations showed no molecular drug-polyester matrix interactions. In vitro dissolution studies suggested a highly tunable biphasic extended release, for up to 30 days, indicating the potential of the synthesized copolymers to act as promising LAI formulations, which will maintain a continuous therapeutic level for an extended time period. Lastly, several empirical and mechanistic models were also tested, with respect to their ability to fit the experimental release data.

Current and emerging long-acting antipsychotics for the treatment of schizophrenia

Introduction: In this review, the authors discuss the role of long-acting injectable antipsychotics (LAIs) for schizophrenia, focusing on the effectiveness and new perspectives introduced by such treatment strategy. Despite their promising pharmacokinetic features and their potential advantages in medication adherence, clinical outcomes, and medical costs, LAIs are not habitually presented as an option for patients, especially in the early phase of schizophrenia.Areas covered: This review explores the panorama of available LAIs for the treatment of schizophrenia, first-episode of psychosis, approved indications, medical costs, medication adherence, side effects, effectiveness and differences between first-generation (FGA)-LAIs and second-generation (SGA)-LAIs.Expert Opinion: LAIs differ in terms of specific indications, approved injection sites, needle size, injection volume, injection interval as well as potential drug-drug interactions, and commonly reported adverse reactions. The approved indications have expanded beyond schizophrenia to include bipolar and schizoaffective disorder. SGA-LAIs are often preferred to FGA-LAIs. FGA-LAIs although are less chosen in new patients due to the induction of cognitive and extrapyramidal side effects, even if, on the other hand, many SGA-LAIs are burden by hyperprolactinemia and weight gain. After a review of the available evidence, insight is provided into the potential and current therapeutic opportunities offered by LAI antipsychotic formulations.

The 'Parma-Early Psychosis' programme: Characterization of help-seekers with first episode psychosis

AIM

Research on early psychosis paradigm has demonstrated the importance of early intervention (EI) in reducing illness severity and persistence. From January 2013, the Parma Department of Mental Health developed a specific care pathway [the 'Parma-Early Psychosis' (Pr-EP) programme] as a diffused EI infrastructure aimed to offer an evidence-based protocol of care to help-seekers with a first episode psychosis (FEP). Aim of this study was to investigate sources of referral, drop-out rate, sociodemographic and clinical characteristics of patients enrolled in the Pr-EP programme during the first 6 years of activity.

METHODS

Participants (n = 279) were individuals (aged 12-54 years) completing an ad-hoc socio-demographic/clinical schedule.

RESULTS

At baseline, the most frequent diagnoses were schizophreniform disorder (30.5%) and schizophrenia (29.4%). Only 31 (11.1%) subjects dropped out during the first year of treatment. FEP participants were mainly referred by general practitioners (36.9%) and emergency room/general hospital (28.7%). FEP individuals who were referred by emergency room/general hospital showed a higher percentage of current suicidal ideation compared to those entering the Pr-EP protocol through other sources of referrals.

CONCLUSIONS

EI in FEP help-seekers within Italian public mental health services is feasible and desirable, also in adolescence, where the risk of falling through the child-adult service gap is high.

Therapeutic Drug Monitoring of Long-Acting Injectable Antipsychotic Drugs

BACKGROUND

The use of therapeutic drug monitoring (TDM) to guide treatment with long-acting injectable (LAI) antipsychotics, which are increasingly prescribed, remains a matter of debate. The aim of this review was to provide a practical framework for the integration of TDM when switching from an oral formulation to the LAI counterpart, and in maintenance treatment.

METHODS

The authors critically reviewed 3 types of data: (1) positron emission tomography data evaluating dopamine (D2/D3) receptor occupancy related to antipsychotic concentrations in serum or plasma; D2/D3 receptors are embraced as target sites in the brain for antipsychotic efficacy and tolerability, (2) pharmacokinetic studies evaluating the switch from oral to LAI antipsychotics, and (3) pharmacokinetic data for LAI formulations. Based on these data, indications for TDM and therapeutic reference ranges were considered for LAI antipsychotics.

RESULTS

Antipsychotic concentrations in blood exhibited interindividual variability not only under oral but also under LAI formulations because these concentrations are affected by demographic characteristics such as age and sex, genetic peculiarities, and clinical variables, including comedications and comorbidities. Reported data combined with positron emission tomography evidence indicated a trend toward lower concentrations under LAI administration than under oral medications. However, the available evidence is insufficient to recommend LAI-specific therapeutic reference ranges.

CONCLUSIONS

Although TDM evidence for newer LAI formulations is limited, this review suggests the use of TDM when switching an antipsychotic from oral to its LAI formulation. The application of TDM practice is more accurate for dose selection than the use of dose equivalents as it accounts more precisely for individual characteristics.

Size matters: the importance of particle size in a newly developed injectable formulation for the treatment of schizophrenia

One of the challenges with initiating long-acting injectable (LAI) antipsychotic regimens is achieving relevant drug levels quickly. After first injection of the LAI antipsychotic aripiprazole lauroxil (AL), the lag to reaching relevant plasma aripiprazole levels was initially addressed using supplemental oral aripiprazole for 21 days. A 1-day AL initiation regimen using a NanoCrystal® Dispersion formulation of AL (ALNCD; Aristada Initio®) combined with a single 30 mg dose of oral aripiprazole has been developed as an alternative approach. We compared the 1-day AL initiation regimen (ALNCD + 30 mg oral aripiprazole for 1 day) with the 21-day AL initiation regimen (AL + 15 mg/day of oral aripiprazole for 21 days) using kinetic modeling. Observed and modeled data demonstrate that the 1-day AL initiation regimen provides continuous aripiprazole exposure comparable to the 21-day AL initiation regimen. Each component of the 1-day AL initiation regimen (30 mg oral aripiprazole, ALNCD, and AL) contributes to aripiprazole plasma levels at different times, with oral aripiprazole predominating in the first week, then ALNCD and AL over time. In a double-blind, placebo-controlled, phase 1 study in patients with schizophrenia, the 1-day initiation regimen resulted in rapid achievement of relevant plasma aripiprazole levels comparable to those from the 21-day initiation regimen. Safety and tolerability of the 1-day regimen were consistent with the known profile of aripiprazole. Each part of the 1-day initiation regimen, together with AL, is necessary for continuous aripiprazole exposure from treatment initiation until the next regularly scheduled AL injection is administered.

Monitoring and improving antipsychotic adherence in outpatient forensic diversion programs

Outpatient diversion programs present an opportunity for severely mentally ill defendants to receive psychiatric treatment and have alleged offenses dismissed by the court. Moreover, the successful completion of pretrial diversion is associated with fewer post-program arrest and jail days. The target patient population for such programs is typically people with schizophrenia spectrum disorders, but the care of such patients in outpatient settings presents challenges for monitoring treatment fidelity, specifically antipsychotic adherence, as low adherence rates are associated with increased rates of recidivism. Presented here is a review of evidence-based strategies that must be employed to track antipsychotic adherence in outpatient diversion programs, including pill counts, use of long-acting injectable antipsychotics, and determination of plasma antipsychotic levels to assess adherence and the adequacy of antipsychotic treatment. Antipsychotic therapy remains the foundation of schizophrenia treatment, but only through the use of all available modalities can clinicians maximize the odds that schizophrenia patients in pretrial diversion maintain psychiatric stability and successfully complete mental health court mandates.

Practical considerations for managing breakthrough psychosis and symptomatic worsening in patients with schizophrenia on long-acting injectable antipsychotics

With more long-acting injectable (LAI) antipsychotics available for treating schizophrenia, each with variable durations of action (2 weeks to 3 months), it is important to have clear management strategies for patients developing breakthrough psychotic symptoms or experiencing symptomatic worsening on LAIs. However, no treatment guidelines or clinical practice pathways exist; health-care providers must rely on their own clinical judgment to manage these patients. This article provides practical recommendations-based on a framework of clinical, pharmacokinetic, and dosing considerations-to guide clinicians' decisions regarding management of breakthrough psychotic symptoms. Management options include ruling out/addressing medical illness or substance abuse/misuse as a contributing factor, addressing stressors, optimizing nonpharmacologic treatments, treating medical/psychiatric comorbidities, ensuring proper LAI administration technique, addressing missed LAI doses or lack of steady-state attainment, and increasing LAI dose directly or indirectly by shortening the injection interval (off-label). If these strategies do not work sufficiently with frequent monitoring, the LAI could be supplemented with a low dose of the corresponding oral formulation for fast symptom control (off-label). However, caution should be exercised with this strategy, because data on the safety of concomitant use of LAI and oral antipsychotics (OAPs) are limited, especially over extended periods. If symptoms abate, therapy optimization could be continued and slow discontinuation of the OAP could be considered. For persistent/worsening symptoms, the OAP should be increased to optimum effective dose while intensifying the initial steps used before it was added. If this fails, switching the OAP or LAI could be considered. We believe that these strategies will help clinicians manage breakthrough psychotic symptoms during LAI treatment and improve overall outcomes among those who can benefit from LAIs.

Optimization of Extended-Release ZL-004 Nanosuspensions for In Vivo Pharmacokinetic Study to Enhance Low Solubility and Compliance

ZL-004, a promising small molecule that increases white blood cell counts, was developed for extended-release nanosuspensions to improve low solubility and compliance of patients. In vivo pharmacokinetic studies of nanosuspensions with different particle sizes and administration volumes were conducted. Unexpectedly, C_max of NS-PC-L (1156 nm) was 1.3 fold higher than NS-PB-L (836 nm), and area under plasma concentration-time curve (AUC) was similar. It suggested that in vivo behavior of nanosuspensions was influenced significantly by the original dissolved drug, which did not only rely on the particle size but also the amount of the free stabilizers. In addition, smaller administration volume (0.1 mL) achieved significantly lower C_max and AUC than the higher volume (0.5 mL), due to the reduced amount of dissolved drug. DSC and XPRD demonstrated that the crystal forms of nanosuspensions prepared by the precipitation method and high-pressure homogenization were similar; therefore, in vivo behaviors did not show significant differences. An additional 0.15% PEG 4000 enhanced the redispersity and maintained the particle size for 3 months. Finally, a nanosuspensions with the desired initial release was achieved, which lasted approximately 32 days steadily after a single dose. AUC and t_1/2 were 161.2 fold and 22.9 fold higher than oral administration.

Impact of initiating long-acting injectable antipsychotics on hospitalization in patients with bipolar I disorder

Aim: To compare risk of hospitalization in patients with bipolar I disorder (BD-I) initiating long-acting injectable antipsychotics (LAIs). Materials & methods: Using Truven Health Analytics MarketScan® (Medicaid, Commercial and Medicare Supplemental) databases (2012–2016), patients (≥18 years) with BD-I with a LAI (aripiprazole once monthly [AOM 400], fluphenazine-LAI, haloperidol-LAI, risperidone-LAI and paliperidone-4-week-LAI) were identified. Results: The adjusted odds of having hospitalization were significantly higher in haloperidol-LAI (Odds ratio [95% CI]: 1.39 [1.03–1.87] all-cause; p = 0.029; 1.41 [1.03–1.93] psychiatric-specific; p = 0.032) and risperidone-LAI (1.54 [1.12–2.13]; p = 0.009; 1.68 [1.20–2.37]; p = 0.003) users versus AOM 400 users. Risks of hospitalization did not differ comparing fluphenazine-LAI and paliperidone-LAI users with AOM 400 users. Conclusion: AOM 400 may be more beneficial at reducing hospitalization rates in BD-I versus haloperidol-LAI and risperidone-LAI.