Dose-dependent effect of lamotrigine on quetiapine serum concentration in patients using instant release tablets

PURPOSE

Lamotrigine was previously reported to reduce serum concentration of quetiapine. The aim of this study was to investigate whether lamotrigine dose or quetiapine formulation was of importance for the drug interaction.

METHODS

Patients combining lamotrigine with quetiapine (cases) were included retrospectively from a routine therapeutic drug monitoring (TDM) service, as were a control group of patients using quetiapine without any interacting drugs. The case and control groups were divided into groups using immediate release (IR) and extended release (XR) quetiapine. The case group was further split into high-dose (> 200 mg/day) and low-dose (≤ 200 mg/day) lamotrigine users. Quetiapine concentration-to-dose (C/D) ratio and metabolite-to-parent ratio (MPR) were compared between the control group and dose-separated case groups using ANOVA test and t-tests.

RESULTS

In total, 406 patients were included. The mean C/D ratio of IR quetiapine was 46% lower in the high-dose lamotrigine group compared with the control group (P < 0.001), while no interaction effect was present in the low dose lamotrigine group (P = 0.7). Regardless of lamotrigine dose, there was no difference in quetiapine C/D ratio for patients using the XR formulation (P = 0.4). The quetiapine MPR was unaffected regardless of formulation and lamotrigine dose (P ≥ 0.06).

CONCLUSION

The effect of lamotrigine in reducing quetiapine concentration is only significant for patients using quetiapine IR tablets who are treated with lamotrigine doses > 200 mg/day. Because of high variability in the interaction effect, TDM of quetiapine should be recommended during co-prescription of high-dose lamotrigine.

Mucoadhesive chitosan-poly (lactic-co-glycolic acid) nanoparticles for intranasal delivery of quetiapine - Development & characterization in physiologically relevant 3D tissue models

Quetiapine hemifumarate (QF) delivery to the CNS via conventional formulations is challenging due to poor solubility and lower oral bioavailability (9 %). Similarly, many other second-generation antipsychotics, such as olanzapine, clozapine, and paliperidone, have also shown low oral bioavailability of <50 %. Hence, the present work was intended to formulate QF-loaded biodegradable PLGA-NPs with appropriate surface charge modification through poloxamer-chitosan and investigate its targeting potential on RPMI-2650 cell lines to overcome the limitations of conventional therapies. QF-loaded poloxamer-chitosan-PLGA in-situ gel (QF-PLGA-ISG) was designed using emulsification and solvent evaporation techniques. Developed QF-PLGA-ISG were subjected to evaluation for particle size, PDI, zeta potential, ex-vivo mucoadhesion, entrapment efficiency (%EE), and drug loading, which revealed 162.2 nm, 0.124, +20.5 mV, 52.4 g, 77.5 %, and 9.7 %, respectively. Additionally, QF-PLGA formulation showed >90 % release within 12 h compared to 80 % of QF-suspension, demonstrating that the surfactant with chitosan-poloxamer polymers could sustainably release medicine across the membrane. Ex-vivo hemolysis study proved that developed PLGA nanoparticles did not cause any hemolysis compared to negative control. Further, in-vitro cellular uptake and transepithelial permeation were assessed using the RPMI-2650 nasal epithelial cell line. QF-PLGA-ISG not only improved intracellular uptake but also demonstrated a 1.5-2-fold increase in QF transport across RPMI-2650 epithelial monolayer. Further studies in the EpiNasal™ 3D nasal tissue model confirmed the safety and efficacy of the developed QF-PLGA-ISG formulation with up to a 4-fold increase in transport compared to plain QF after 4 h. Additionally, histological reports demonstrated the safety of optimized formulation. Finally, favorable outcomes of IN QF-PLGA-ISG formulation could provide a novel platform for safe and effective delivery of QF in schizophrenic patients.

Pharmacokinetic/pharmacodynamic modeling of cortical dopamine concentrations after quetiapine lipid core nanocapsules administration to schizophrenia phenotyped rats

Schizophrenia (SCZ) response to pharmacological treatment is highly variable. Quetiapine (QTP) administered as QTP lipid core nanocapsules (QLNC) has been shown to modulate drug delivery to the brain of SCZ phenotyped rats (SPR). In the present study, we describe the brain concentration-effect relationship after administrations of QTP as a solution or QLNC to SPR and naïve animals. A semimechanistic pharmacokinetic (PK) model describing free QTP concentrations in the brain was linked to a pharmacodynamic (PD) model to correlate the drug kinetics to changes in dopamine (DA) medial prefrontal cortex extracellular concentrations determined by intracerebral microdialysis. Different structural models were investigated to fit DA concentrations after QTP dosing, and the final model describes the synthesis, release, and elimination of DA using a pool compartment. The results show that nanoparticles increase QTP brain concentrations and DA peak after drug dosing to SPR. To the best of our knowledge, this is the first study that combines microdialysis and PK/PD modeling in a neurodevelopmental model of SCZ to investigate how a nanocarrier can modulate drug PK and PD, contributing to the development of new treatment strategies for SCZ.

Dutch Pharmacogenetics Working Group (DPWG) guideline for the gene-drug interaction between CYP2D6, CYP3A4 and CYP1A2 and antipsychotics

The Dutch Pharmacogenetics Working Group (DPWG) aims to facilitate pharmacogenetics implementation in clinical practice by developing evidence-based guidelines to optimize pharmacotherapy. A guideline describing the gene-drug interaction between the genes CYP2D6, CYP3A4 and CYP1A2 and antipsychotics is presented here. The DPWG identified gene-drug interactions that require therapy adjustments when respective genotype is known for CYP2D6 with aripiprazole, brexpiprazole, haloperidol, pimozide, risperidone and zuclopenthixol, and for CYP3A4 with quetiapine. Evidence-based dose recommendations were obtained based on a systematic review of published literature. Reduction of the normal dose is recommended for aripiprazole, brexpiprazole, haloperidol, pimozide, risperidone and zuclopenthixol for CYP2D6-predicted PMs, and for pimozide and zuclopenthixol also for CYP2D6 IMs. For CYP2D6 UMs, a dose increase or an alternative drug is recommended for haloperidol and an alternative drug or titration of the dose for risperidone. In addition, in case of no or limited clinical effect, a dose increase is recommended for zuclopenthixol for CYP2D6 UMs. Even though evidence is limited, the DPWG recommends choosing an alternative drug to treat symptoms of depression or a dose reduction for other indications for quetiapine and CYP3A4 PMs. No therapy adjustments are recommended for the other CYP2D6 and CYP3A4 predicted phenotypes. In addition, no action is required for the gene-drug combinations CYP2D6 and clozapine, flupentixol, olanzapine or quetiapine and also not for CYP1A2 and clozapine or olanzapine. For identified gene-drug interactions requiring therapy adjustments, genotyping of CYP2D6 or CYP3A4 prior to treatment should not be considered for all patients, but on an individual patient basis only.

A validated method for the determination of quetiapine fumarate tablets in human plasma by UPLC-MS/MS and its application to a pharmacokinetic study in healthy Chinese subjects

A rapid, highly specific and sensitive UPLC-MS/MS method was developed for the determination of Quetiapine Fumarate, a therapeutic drug for various psychiatric disorders, in human plasma. The samples were pretreated using a protein precipitation method, followed by chromatographic separation using a column (Kinetex C18, 2.6µm 50*2.1mm) equipped with an ESI source and MRM mode mass spectrometer. In the validation results of the method, the analyte quetiapine showed a peak at approximately 1.0 minute and exhibited good linearity within the concentration from 2.5 to 2000ng/mL. The intra- and inter-batch precision CV% were within the range of -1.3% to 7.7% and precision of intra- and inter-batch were below 15.0%. Furthermore, this method demonstrated low matrix effects and high recovery rates. The quetiapine plasma sample solution remained stable at room temperature for 25 hours and following 4 freeze-thaw cycles. The prepared samples remained stable in the autosampler (The temperature control of the autosampler was 5oC) for 185 hours and after four freeze-thaw cycles at -20oC and -70oC for 40 days. The present work effectively employed this approach to investigate the pharmacokinetics of orally administered quetiapine fumarate tablets in a cohort of healthy Chinese individuals, both in a fasting state and after a meal.

Innovative spectrofluorometric protocol based on micro-environment improvement for determination of Quetiapine in dosage forms and rat plasma

Quetiapine (QUT) is an atypical antipsychotic drug indicated for the treatment of schizophrenia and acute manic episodes associated with bipolar disorders. A simple, rapid, and highly sensitive micellar spectrofluorometric method has been developed and validated for quantitation of QUT in its pharmaceutical formulations with application to content uniformity test, in presence of its degradation product and in rat plasma. The proposed method was based on the enhancement of the fluorescence intensity of QUT in 2% v/v tween 80 micellar solution. The fluorescence intensity was measured at 372 nm after excitation at 261 nm. A linear relationship was achieved between the fluorescence intensity and the drug concentration in the range of 20-1000 ng/mL with 18.5 and 6.3 ng/mL as limits of quantitation and detection, respectively. The proposed method was extended to study the stability of QUT after its exposure to different forced degradation conditions such as; acidic, alkaline, oxidative, photolytic and thermal conditions according to ICH guidelines. The study revealed that QUT is stable under all the of these conditions except the oxidative one. Furthermore, the high sensitivity of the micellar method permits its application for determination of QUT in rat plasma with good percentage recovery as well as determination of C_max.

Quality by Design Approach for Development and Characterisation of Solid Lipid Nanoparticles of Quetiapine Fumarate

BACKGROUND

Quetiapine fumarate, a 2nd generation anti-psychotic drug has oral bioavailability of 9% because of hepatic first pass metabolism. Reports suggest that co-administration of drugs with lipids affects their absorption pathways, enhances lymphatic transport thus bypassing hepatic first-pass metabolism resulting in enhanced bioavailability.

OBJECTIVE

The present work aimed at developing, and characterising potentially lymphatic absorbable Solid Lipid Nanoparticles (SLN) of quetiapine fumarate by Quality by Design approach.

METHODS

Hot emulsification followed by ultrasonication was used as a method of preparation. Precirol ATO5, Phospholipon 90G and Poloxamer 188 were used as a lipid, stabilizer and surfactant respectively. A32 Central Composite design optimised the 2 independent variables, lipid concentration and stabilizer concentration and assessed their effect on percent Entrapment Efficiency (%EE: Y1). The lyophilized SLNs were studied for stability at 5 ±3οC and 25 ± 2οC/60 ± 5% RH for 3 months.

RESULTS

The optimised formula derived for SLN had 270mg Precirol ATO5 and 107mg of Phospholipon 90G giving %EE of 76.53%. Mean particle size was 159.8nm with polydispersity index 0.273 and zeta potential -6.6mV. In-vitro drug release followed Korsmeyer-Peppas kinetics (R2=0.917) with release exponent n=0.722 indicating non-Fickian diffusion. Transmission electron microscopy images exhibited particles to be spherical and smooth. Fourier-transform infrared spectroscopy, differential scanning calorimetry and X-ray diffraction studies ascertained drug-excipient compatibility. Stability studies suggested 5οC as appropriate temperature for storage and preserving important characteristics within acceptable limits.

CONCLUSION

Development and optimisation by Quality by Design were justified as it yielded SLN having acceptable characteristics and potential application for intestinal lymphatic transport.

Pharmacokinetic evaluation of quetiapine fumarate controlled release hybrid hydrogel: a healthier treatment of schizophrenia

The current study aimed to rationally develop and characterize pH-sensitive controlled release hydrogels by graft polymerization of gelatin (Gel) and hydroxypropyl methyl cellulose (HPMC) in the presence of glutaraldehyde (GA) using quetiapine fumarate for the treatment of schizophrenia. The prepared hydrogels discs were subjected to various physicochemical studies including: swelling, diffusion, porosity, sol-gel analysis, Fourier transform infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy. Three different pH values (1.2, 6.8 and 7.4) were used to determine shape, transition, and controlled release behavior of prepared hydrogels. Various kinetic models including zero order, first order, Higuchi model and Power Law equation were applied on drug release data. The optimized hydrogels were subjected to in vivo studies using albino rabbits. Swelling and release results were found to be insignificant (p < .05) evidencing that there was no significant difference in swelling and drug release rate of hydrogels in different pH mediums. Swelling, porosity, gel-fraction, and drug released (%) were found to be dependent on concentrations of Gel, HPMC, and GA. Kinetic models revealed that QTP-F release followed non-Fickian diffusion. In-vivo studies contributed significantly higher plasma QTP-F concentration (Cmax), time for maximum plasma concentration (Tmax), area under the curve (AUC0-inf) and half-life (t1/2) as 18.32 ± 0.50 µg/ml, 8.00 ± 0.01 hrs, 6021.2 ± 5.09 µg.hrs/ml and 10.06 ± 0.43 hrs, respectively, for test-hydrogels when compared to reference market brand (Qusel® 200 mg, Hilton Pharma, Karachi, Pakistan) QTP-F tablets. It might be concluded that QTP-F loaded pH-sensitive hydrogels were developed successfully with reduced dosing frequency for schizophrenia.

[Delirium as a late onset manifestation of quetiapine intoxication]

In this article we describe the developments of two patients who were hospitalized after a quetiapine overdose, subsequently developing delirium. Delirium occurred several hours after ingestion and lasted several days. Laboratory blood testing revealed a slower decline in quetiapine plasma concentration than expected when compared to the standardized half-life averages of therapeutic doses of quetiapine. The clinical state during the first hours after ingestion does not sufficiently predict further clinical outcome. The changes in pharmacokinetics due to the intoxication, so-called toxicokinetics, are the underlying cause.

How long does the pharmacokinetic interaction between carbamazepine and quetiapine last after carbamazepine withdrawal?

OBJECTIVES

Carbamazepine and quetiapine are drugs that are used as mood stabilizers in the treatment of bipolar disorders. A series of studies has shown that concurrent use of carbamazepine decreases quetiapine serum level due to induction of CYP3A enzymes by carbamazepine.

METHODS

In a 30-year-old bipolar patient with mania treated with quetiapine 1200 mg and carbamazepine 900 mg per day, we measured quetiapine serum level before and after carbamazepine withdrawal.

RESULTS

No serum quetiapine was detected during concurrent use of carbamazepine and was lower than the therapeutic range almost 2 weeks after carbamazepine withdrawal. The patient suffered from sedation when her serum level of quetiapine was 181 ng/ml and because she was quiet we started slowly to decrease to a quetiapine dose of 600 mg. Her serum level (45 ng/ml) was again below therapeutic levels after 3 weeks of carbamazepine withdrawal.

CONCLUSION

We hypothesize that induction of CYP3A lasts even after carbamazepine withdrawal. Our hypothesis was confirmed during the next treatment of mania. The patient had been off carbamazepine for 1 year and her serum level was four times higher (210 ng/ml) on 600 mg of quetiapine than 3 weeks after carbamazepine withdrawal. The influence of carbamazepine on CYP3A enzymes lasted at least 3 weeks after carbamazepine withdrawal which is in accordance with CYP3A de-induction lasting 3 weeks. This could be important information for psychiatrists to know that in some patients it is better to use a minimum washout period of 3 weeks for carbamazepine before new treatment with quetiapine.