6-Carboxycellulose Acetate Butyrate: Effectiveness as an Amorphous Solid Dispersion Polymer.

Amorphous solid dispersion (ASD) in a polymer matrix is a powerful method for enhancing the solubility and bioavailability of otherwise crystalline, poorly water-soluble drugs. 6-Carboxycellulose acetate butyrate (CCAB) is a relatively new commercial cellulose derivative that was introduced for use in waterborne coating applications. As CCAB is an amphiphilic, carboxyl-containing, high glass transition temperature (Tg) polymer, characteristics essential to excellent ASD polymer performance, we chose to explore its ASD potential. Structurally diverse drugs quercetin, ibuprofen, ritonavir, loratadine, and clarithromycin were dispersed in CCAB matrices. We evaluated the ability of CCAB to create ASDs with these drugs and its ability to provide solubility enhancement and effective drug release. CCAB/drug dispersions prepared by spray drying were amorphous up to 25 wt % drug, with loratadine remaining amorphous up to 50% drug. CCAB formulations with 10% drug proved effective at providing in vitro solubility enhancement for the crystalline flavonoid drug quercetin as well as ritonavir, but not for the more soluble APIs ibuprofen and clarithromycin and the more hydrophobic loratadine. CCAB did provide slow and controlled release of ibuprofen, offering a simple and promising Long-duration ibuprofen formulation. Formulation with clarithromycin showed the ability of the polymer to protect against degradation of the drug at stomach pH. Furthermore, CCAB ASDs with both loratadine and ibuprofen could be improved by the addition of the water-soluble polymer poly(vinylpyrrolidone) (PVP), with which CCAB shows good miscibility. CCAB provided solubility enhancement in some cases, and the slower drug release exhibited by CCAB, especially in the stomach, could be especially beneficial, for example, in formulations containing known stomach irritants like ibuprofen.

Clinical efficacy and safety study of Loratadine combined with glucocorticoid nasal spray in the treatment of pediatric bronchial asthma with seasonal allergic rhinitis.

OBJECTIVE: To investigate the clinical efficacy and safety of Loratadine combined with Glucocorticoid nasal spray in the treatment of pediatric bronchial asthma with seasonal allergic rhinitis. METHODS: A total of 100 pediatric patients with moderate to severe bronchial asthma and seasonal allergic rhinitis admitted to our hospital between January 2020 and January 2023 were included in this study. All patients met the complete inclusion and exclusion criteria. Based on different treatment interventions, they were divided into the control group (n = 50) and the observation group (n = 50). Patients in the control group received treatment with glucocorticoid nasal spray, while patients in the observation group received combined intervention with Loratadine in addition to the treatment received by the control group. The clinical treatment outcomes, incidence of adverse reactions, as well as the scores of nasal symptoms, asthma control, and peak expiratory flow rates at different treatment time points (baseline, T1: 30 days after treatment, T2: 60 days after treatment, T3: 90 days after treatment) were compared between the two groups. The combined treatment of Loratadine with Glucocorticoid nasal spray demonstrates significant clinical efficacy in the treatment of pediatric bronchial asthma with seasonal allergic rhinitis. It further promotes the recovery of peak expiratory flow rates, improves symptoms of rhinitis and asthma in pediatric patients. Importantly, the application of this combined treatment does not increase the risk of adverse reactions in pediatric patients, indicating its high safety profile. This treatment approach is worthy of clinical application and further promotion.

Cost-effectiveness Analysis of Second-Generation Antihistamine 1 Receptor Blockers and Japanese Kampo Shoseiryuto for Treating Perennial Allergic Rhinitis in Outpatient Settings in Japan.

Objectives: Perennial allergic rhinitis (PAR) is common in Japan. Second-generation antihistamines (SGAs) are commonly used for its treatment; however, it remains unclear which SGA is the most cost-effective. Additionally, the pharmacoeconomics of Japanese Kampo shoseiryuto (which was traditionally prescribed to treat PAR in Japan) remains poorly understood. In this study, we aimed to investigate the effectiveness of various SGAs and shoseiryuto for the treatment of PAR in Japanese outpatients, from the healthcare payer's perspective. Methods: The most cost- and clinically effective SGAs were determined from a list of 6 SGAs (bepotastine, 10 mg; cetirizine, 10 mg; ebastine, 10 mg; epinastine, 20 mg; loratadine, 10 mg; and olopatadine, 5 mg) together with shoseiryuto, using the overall improvement rate through a model-based analysis. The time horizon was 28 days. Costs were determined based on the Medical Fee Index in 2020. Deterministic and probabilistic sensitivity analyses were conducted to address the uncertainty of the base-case results. Results: Overall, bepotastine (10 mg) and ebastine (10 mg) were cost-effective. Shoseiryuto was less cost-effective than ebastine (10 mg) (dominated). Ebastine (10 mg) was the most cost-effective option based on deterministic and probabilistic sensitivity analyses. Conclusions: Ebastine (10 mg) was the most cost-effective treatment strategy for PAR among the agents evaluated in this study. This insight could aid in establishing an appropriate formulary for treating PAR in hospitals and communities.

Computational modeling (in silico) methods combined with ecotoxicological experiments (in vivo) to predict the environmental risks of an antihistamine drug (loratadine).

This study employed computational modeling (in silico) methods, combined with ecotoxicological experiments (in vivo) to predict the persistence/biodegradability, bioaccumulation, mobility, and ecological risks of an antihistamine drug (Loratadine: LOR) in the aquatic compartment. To achieve these goals, four endpoints of the LOR were obtained from different open-source computational tools, namely: (i) "STP total removal"; (ii) Predicted ready biodegradability; (iii) Octanol-water partition coefficient (KOW); and (iv) Soil organic adsorption coefficient (KOC). Moreover, acute and chronic, ecotoxicological assays using non-target freshwater organisms of different trophic levels (namely, algae Pseudokirchneriella subcapitata; microcrustaceans Daphnia similis and Ceriodaphnia dubia; and fish Danio rerio), were used to predict the ecological risks of LOR. The main results showed that LOR: (i) is considered persistent (after a weight-of-evidence assessment) and highly resistant to biodegradation; (ii) is hydrophobic (LOG KOW = 5.20), immobile (LOG KOC = 5.63), and thus, it can potentially bioaccumulate and/or can cause numerous deleterious effects in aquatic species; and (iii) after ecotoxicological evaluation is considered "toxic" and/or "highly toxic" to the three trophic levels tested. Moreover, both the ecotoxicological assays and risk assessment (RQ), showed that LOR is more harmful for the crustaceans (RQcrustaceans = moderate to high risks) than for algae and fish. Ultimately, this study reinforces the ecological concern due to the indiscriminate disposal of this antihistamine drug in worldwide aquatic ecosystems.

Real-world practice of the Egyptian Kelleni's protocol amid changing tropism of SARS-CoV-2 omicron BA.5.2.1.7, XBB 1.5 and CH.1.1 subvariants: a multi-purpose protocol.

The Egyptian immune-modulatory Kelleni's protocol, including nitazoxanide as an integral component, is being safely and effectively practiced to manage SARS-CoV-2, RSV, influenza infections in pediatric, adult and pregnant patients with negligible requirements for the relatively expensive diagnostic molecular tests. Most recently, Kelleni's protocol is being likewise used to manage potential norovirus infection which is currently confused with SARS-CoV-2 Omicron new enterotropic subvariants and the antihistaminic loratadine has been co-administered in selected patients. Notably, Africa has the least mandates, restrictions and SARS-CoV-2 vaccination rates and yet the least COVID-19 mortality.

Network Pharmacology Study to Elucidate the Key Targets of Underlying Antihistamines against COVID-19.

Antihistamines have potent efficacy to alleviate COVID-19 (Coronavirus disease 2019) symptoms such as anti-inflammation and as a pain reliever. However, the pharmacological mechanism(s), key target(s), and drug(s) are not documented well against COVID-19. Thus, we investigated to decipher the most significant components and how its research methodology was utilized by network pharmacology. The list of 32 common antihistamines on the market were retrieved via drug browsing databases. The targets associated with the selected antihistamines and the targets that responded to COVID-19 infection were identified by the Similarity Ensemble Approach (SEA), SwissTargetPrediction (STP), and PubChem, respectively. We described bubble charts, the Pathways-Targets-Antihistamines (PTA) network, and the protein-protein interaction (PPI) network on the RPackage via STRING database. Furthermore, we utilized the AutoDock Tools software to perform molecular docking tests (MDT) on the key targets and drugs to evaluate the network pharmacological perspective. The final 15 targets were identified as core targets, indicating that Neuroactive ligand-receptor interaction might be the hub-signaling pathway of antihistamines on COVID-19 via bubble chart. The PTA network was constructed by the RPackage, which identified 7 pathways, 11 targets, and 30 drugs. In addition, GRIN2B, a key target, was identified via topological analysis of the PPI network. Finally, we observed that the GRIN2B-Loratidine complex was the most stable docking score with -7.3 kcal/mol through molecular docking test. Our results showed that Loratadine might exert as an antagonist on GRIN2B via the neuroactive ligand-receptor interaction pathway. To sum up, we elucidated the most potential antihistamine, a key target, and a key pharmacological pathway as alleviating components against COVID-19, supporting scientific evidence for further research.

Evaluation of biotransformation capacity of transplastomic plants and hairy roots of Nicotiana tabacum expressing human cytochrome P450 2D6.

Cytochrome P450 monooxygenases (CYPs) are important tools for regio- and stereoselective oxidation of target molecules or engineering of metabolic pathways. Functional heterologous expression of eukaryotic CYPs is often problematic due to their dependency on the specific redox partner and the necessity of correct association with the membranes for displaying enzymatic activity. Plant hosts offer advantages of accessibility of reducing partners and a choice of membranes to insert heterologous CYPs. For the evaluation of plant systems for efficient CYP expression, we established transplastomic plants and hairy root cultures of Nicotiana tabacum carrying the gene encoding human CYP2D6 with broad substrate specificity. The levels of CYP2D6 transcript accumulation and enzymatic activity were estimated and compared with the data of CYP2D6 transient expression in N. benthamiana. The relative level of CYP2D6 transcripts in transplastomic plants was 2-3 orders of magnitude higher of that observed after constitutive or transient expression from the nucleus. CYP2D6 expressed in chloroplasts converted exogenous synthetic substrate loratadine without the need for co-expression of the cognate CYP reductase. The loratadine conversion rate in transplastomic plants was comparable to that in N. benthamiana plants transiently expressing a chloroplast targeted CYP2D6 from the nucleus, but was lower than the value reported for transiently expressed CYP2D6 with the native endoplasmic reticulum signal-anchor sequence. Hairy roots showed the lowest substrate conversion rate, but demonstrated the ability to release the product into the culture medium. The obtained results illustrate the potential of plant-based expression systems for exploiting the enzymatic activities of eukaryotic CYPs with broad substrate specificities.

Anti-Inflammatory Activities of an Anti-Histamine Drug, Loratadine, by Suppressing TAK1 in AP-1 Pathway.

Loratadine is an anti-histamine routinely used for treating allergies. However, recent findings have shown that Loratadine may also have anti-inflammatory functions, while their exact mechanisms have not yet been fully uncovered. In this paper, we investigated whether Loratadine can be utilized as an anti-inflammatory drug through a series of in vitro and in vivo experiments using a murine macrophage cell line and an acute gastritis mouse model. Loratadine was found to dramatically reduce the expression of pro-inflammatory genes, including MMP1, MMP3, and MMP9, and inhibit AP-1 transcriptional activation, as demonstrated by the luciferase assay. Therefore, we decided to further explore its role in the AP-1 signaling pathway. The expression of c-Jun and c-Fos, AP-1 subunits, was repressed by Loratadine and, correspondingly, the expression of p-JNK, p-MKK7, and p-TAK1 was also inhibited. In addition, Loratadine was able to reduce gastric bleeding in acute gastritis-induced mice; Western blotting using the stomach samples showed reduced p-c-Fos protein levels. Loratadine was shown to effectively suppress inflammation by specifically targeting TAK1 and suppressing consequent AP-1 signaling pathway activation and inflammatory cytokine production.

Nanosized-Loratadine Embedded Orodispersible Films for Enhanced Bioavailability: Scalable Preparations and Characterizations.

The patient-centric strategy urges the pharmaceutical companies to develop orodispersible films (ODF) as a new approach for pediatrics. However, the most common ODF-fabricated method, solvent casting, is facing the safety challenges of safety during manufacturing. To obtain favorable formulations with the ease of use and rapid dissolution, nanotechnology has been accounted for the development process. In this work, we investigated the wet-milling technique in preparing nanocarriers for loratadine-a hydrophobic anti-histamine drug. The results showed that the wet-milling technique could produce nanocarriers at the size of 400 nm. The reduction of particle size induced the increase of solubility and the dissolution rate of loratadine. Moreover, the pre-formulation of nanosized materials could adapt to the preparation of orodispersible films that disintegrated (less than 60s) and dissolved quickly. The DSC results showed that after the milling process, the crystallinity of loratadine was unchanged; however, the reduction in size induced an enhancement of drug bioavailability. After orally administrated to rats, the drug was quickly reached to the blood circulation, just after 30 min. Cmax increased from 44.97 ng/mL for the raw drug to 101.02 ng/mL for the nanocrystal leading to an enhancement of the AUC0-24h by 5.69-fold when the nanocrystal ODF was administrated. The ease of formulation and the improvement of drug solubility as well as bioavailability potentiated orodispersible films as a promising drug delivery for loratadine. Graphical abstract.

Computational and Experimental Models of Type III Lipid-Based Formulations of Loratadine Containing Complex Nonionic Surfactants.

Type III lipid-based formulations (LBFs) combine poorly water-soluble drugs with oils, surfactants, and cosolvents to deliver the drugs into the systemic circulation. However, the solubility of the drug can be influenced by the colloidal phases formed in the gastrointestinal tract as the formulation is dispersed and makes contact with bile and other materials present within the GI tract. Thus, an understanding of the phase behavior of LBFs in the gut is critical for designing efficient LBFs. Molecular dynamics (MD) simulation is a powerful tool for the study of colloidal systems. In this study, we modeled the internal structures of five type III LBFs of loratadine containing poly(ethylene oxide) nonionic surfactants polysorbate 80 and polyoxyl hydrogenated castor oil (Kolliphor RH40) using long-timescale MD simulations (0.4-1.7 µs). We also conducted experimental investigations (dilution of formulations with water) including commercial Claritin liquid softgel capsules. The simulations show that LBFs form continuous phase, water-swollen reverse micelles, and bicontinuous and phase-separated systems at different dilutions, which correlate with the experimental observations. This study supports the use of MD simulation as a predictive tool to determine the fate of LBFs composed of medium-chain lipids, polyethylene oxide surfactants, and polymers.

Efficiency and safety of desloratadine in combination with compound glycyrrhizin in the treatment of chronic urticaria: a meta-analysis and systematic review of randomised controlled trials.

CONTEXT: Desloratadine, an H1 receptor antagonist, is suggested as an effective first-line drug for chronic urticarial (CU). However, the efficacy of desloratadine alone is limited, and the recurrence rate of CU is relatively high. OBJECTIVE: We sought to evaluate the efficacy and clinical feasibility of desloratadine in combination with compound glycyrrhizin in the treatment of CU. MATERIALS AND METHODS: A systematic literature search was conducted in the databases of the China National Knowledge Infrastructure Database, VIP, WanFang, PubMed, and Web of Science using subject terms: "Chronic urticaria", "Loratadine", and "Compound glycyrrhizin". Randomised controlled trials (RCTs) that compared the efficiency and safety of the combination treatment with desloratadine alone starting from January 1, 2014 until February 10, 2021 were selected by two co-first authors independently, and the extracted data were analysed using Rev Man 5.3 software. RESULTS: Fourteen RCTs were included in our meta-analysis with a total of 1501 patients. The results showed that the combination treatment yielded a better treatment effect (total response rate: RR = 1.23, 95% CI: 1.17 to 1.29, p < 0.00001; cure rate: RR = 1.50, 95% CI: 1.30 to 1.73, p < 0.00001), lower recurrence rate as well as superior immune improvement than the treatment with desloratadine alone. In addition, there was no significant difference in the safety of the two treatments. DISCUSSION AND CONCLUSION: The combination of desloratadine and compound glycyrrhizin is a promising treatment for CU and is associated with decreased serum IgE level and improved proportions of CD4+ T and CD8+ T cells.

Efficacy and Pharmacokinetic Considerations of Loratadine Nanoformulations and its Combinations for Pancreatic Cancer Chemoprevention.

PURPOSE: Pancreatic cancer (PC) is predicted to become the second leading cause of cancer associated deaths by 2020. Earlier, we confirmed the development and efficacy of our novel Loratadine Self-Microemulsifying-Drug-Delivery-System - Sulforaphane (LOR SMEDDS -SFN) nanoformulation in PC chemoprevention. In this report, we extend our studies to evaluate the PC chemoprevention efficacy of LOR SMEDDS - SFN. METHODS: The nanoformulation was subjected to in vitro colony formation assays, in vivo oral pharmacokinetics and stability studies. RESULTS: The colony formation assay using Panc-1 PC cells demonstrated a survival fraction of 0.74 with LOR-SFN (p < 0.001) which further reduced to 0.35 with LOR SMEDDS-SFN treatment (p < 0.0001) confirming the synergistic chemoprevention efficacy of the nanoformulation. Further, the oral pharmacokinetic studies of LOR SMEDDS-SFN showed 4-fold and 9-fold increase in Cmax (503.2 ± 5.8 ng/mL) and oral bioavailability (20,274.8 ± 3711.0 ng·h/mL) for LOR compared to LOR-SFN combination respectively assuring the enhanced performance by the SMEDDS. Additionally, the formulation exhibited statistically non-significant alteration in globule size, zeta potential, drug content and in vitro drug release during stability studies confirming its stability and pharmaceutical acceptability. CONCLUSION: Our studies have demonstrated a potential of LOR SMEDDS-SFN nanoformulation as an effective PC chemoprevention strategy.

Molecular Origin of the Distinct Tabletability of Loratadine and Desloratadine: Role of the Bonding Area - Bonding Strength Interplay.

PURPOSE: To explain the different tabletability of two structurally similar H1-receptor antihistamine drugs, loratadine (LOR) and desloratadine (DES), based on the molecular basis of bonding area and bonding strength. METHODS: LOR and DES were characterized by powder X-ray diffractometry, thermal analysis, and dynamic water sorption. The compressibility, tabletability, compactibility, and Heckel analysis of their bulk powders and formulations were evaluated. A combined energy framework and topological analysis was used to characterize the crystal structure - mechanical property relationship. Surface energy of bulk powder was assessed by contact angle measurement using the Owens/Wendt theory. RESULTS: Both LOR and DES bulk powders are phase pure and stable under compaction. The superior tabletability of LOR is attributed to both larger bonding area (BA) and higher interparticle bonding strength (BS). The larger BA of LOR results from its experimentally established higher plasticity, which is explained by the presence of more densely packed molecular layers with smooth surface topology. The higher BS of LOR corresponded to its significantly higher dispersive component of the surface energy. CONCLUSIONS: This work provides new insights into the molecular origins of BA and BS, which can be applied to improve mechanical properties and tableting performance of drugs through appropriate crystal engineering.

Hepatocyte spheroids as a viable in vitro model for recapitulation of complex in vivo metabolism pathways of loratadine in humans.

Accurate prediction of in vivo metabolic pathways in humans can be challenging because in vitro liver matrices may fail to produce certain in vivo metabolites.Rat and human spheroids, generated from cryopreserved hepatocytes in media that contained minimal amount of serum, maintained morphology, viability and cytochrome P450 (CYP) activities for at least a week without media exchange.With spheroid cultures, multiple Phase I and Phase II metabolites were observed in rat and human spheroid cultures that were incubated with loratadine (LOR) for multiple days. Consistent with in vivo observations, 3-hydroxydesloratadine, (3-OH-DL), along with its glucuronide, were observed in human spheroids, but not in rat spheroids. Interestingly, the putative intermediate metabolite leading to 3-OH-DL, DL-N-glucuronide, was observed in incubations with both rat and human spheroids. In conclusion, hepatocyte spheroid were capable of recapitulating the inter-species differences in metabolism between human and rat for LOR, therefore, it may represent a viable model for studying complex metabolic pathways.

The combination of loratadine with famotidine to relieve the symptoms of urinary frequency in female patients with bladder function disorders：First report of three cases.

WHAT IS KNOWN AND OBJECTIVES: Urinary frequency is a common presentation of bladder function disorders in female patients. Few medicines are effective in all patients. The use of loratadine combined with famotidine had not been previously reported for this indication. CASE DESCRIPTION: Three female patients complaining of urinary frequency had been given loratadine at 10 mg QD combined with famotidine 20 mg BID for about 5 months. They all achieved symptom improvement. WHAT IS NEW AND CONCLUSION: The combination of loratadine with famotidine was used to treat urinary frequency. It was safe, effective, and convenient, and may be an option for oral medical therapy in female patients with bladder function disorders.

Ecotoxic effects of loratadine and its metabolic and light-induced derivatives.

Loratadine and desloratadine are second-generation antihistaminic drugs. Because of human administration, they are continuously released via excreta into wastewater treatment plants and occur in surface waters as residues and transformation products (TPs). Loratadine and desloratadine residues have been found at very low concentrations (ng/L) in the aquatic environment but their toxic effects are still not well known. Both drugs are light-sensitive even under environmentally simulated conditions and some of the photoproducts have been isolated and characterized. The aim of the present study was to investigate the acute and chronic ecotoxicity of loratadine, desloratadine and their light-induced transformation products in organisms of the aquatic trophic chain. Bioassays were performed in the alga Pseudokirchneriella subcapitata, the rotifer Brachionus calyciflorus and in two crustaceans, Thamnocephalus platyurus and Ceriodaphnia dubia. Loratadine exerted its acute and chronic toxicity especially on Ceriodaphnia dubia (LC50: 600 µg/L, EC50: 28.14 µg/L) while desloratadine showed similar acute toxicity among the organisms tested and it was the most chronically effective compound in Ceriodaphnia dubia and Pseudokirchneriella subcapitata. Generally, transformation products were less active in both acute and chronic assays.

Oral loratadine in the management of G-CSF-induced bone pain: a pilot study.

This pilot study aimed to ascertain if bone pain induced by granulocyte-colony stimulating factors (G-CSFs) can be alleviated or eliminated by oral antihistamine loratadine. Twelve patients with cancer receiving chemotherapy were included in the study. Daily pain increased between before treatment started and after cycle 1 in all patients. All 12 participants were started on loratadine on cycle 2; three patients were taking pain medications in addition to this as needed, which were ibruprofen (n=1) or tramadol (n=2). Pain decreased towards the later cycles after patients were started on loratadine in cycle 2, with the exception of one patient who also took tramadol as needed in cycle 3. Oral loratadine was found to be associated with pain reduction in patients with cancer receiving G-CSFs.

NOLAN: a randomized, phase 2 study to estimate the effect of prophylactic naproxen or loratadine vs no prophylactic treatment on bone pain in patients with early-stage breast cancer receiving chemotherapy and pegfilgrastim.

PURPOSE: Mild-to-moderate bone pain is a commonly reported adverse event (AE) associated with pegfilgrastim. We evaluated the effect of prophylactic naproxen or loratadine vs no prophylactic treatment on pegfilgrastim-associated bone pain. METHODS: In this open-label study (NCT01712009), women ≥ 18 years of age with newly diagnosed stage I-III breast cancer and an ECOG performance status ≤ 2 who were planning ≥ 4 cycles of adjuvant or neoadjuvant chemotherapy with pegfilgrastim support starting in cycle 1 were randomized 1:1:1 to receive naproxen, loratadine, or no treatment to prevent pegfilgrastim-associated bone pain. The primary endpoint was all-grade bone pain in cycle 1 from AE reporting. Secondary endpoints included bone pain in cycles 2-4 and across all cycles from AE reporting and patient-reported bone pain by cycle and across all cycles. RESULTS: Six hundred patients were enrolled. Most patients (83.0%) were white, and mean (SD) age was 54.2 (11.1) years. The percentage of patients with all-grade bone pain in cycle 1 from AE reporting in the naproxen, loratadine, and no prophylaxis groups was 40.3, 42.5, and 46.6%, respectively; differences between the treatment groups were not statistically significant. Maximum, mean, and area under the curve for patient-reported bone pain were consistently lower in the naproxen and loratadine groups than in the no prophylaxis group; some of these differences were significant. Loratadine was associated with fewer treatment-related AEs and discontinuations than naproxen. CONCLUSIONS: Given its tolerability, its ease of administration, and its potential benefit, treatment with loratadine should be considered to help prevent bone pain in patients receiving chemotherapy and pegfilgrastim. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov ; NCT01712009.

D-Optimal mixture design optimization of an HPLC method for simultaneous determination of commonly used antihistaminic parent molecules and their active metabolites in human serum and urine.

This study describes a specific, precise, sensitive and accurate method for simultaneous determination of hydroxyzine, loratadine, terfenadine, rupatadine and their main active metabolites cetirizine, desloratadine and fexofenadine, in serum and urine using meclizine as an internal standard. Solid-phase extraction method for sample clean-up and preconcentration of analytes was carried out using Phenomenex Strata-X-C and Strata X polymeric cartridges. Chromatographic analysis was performed on a Phenomenex cyano (150 × 4.6 mm i.d., 5 µm) analytical column. A D-optimal mixture design methodology was used to evaluate the effect of changes in mobile phase compositions on dependent variables and optimization of the response of interest. The mixture design experiments were performed and results were analyzed. The region of ideal mobile phase composition consisting of acetonitrile-methanol-ammonium acetate buffer (40 mm; pH 3.8 adjusted with acetic acid): 18:36:46% v/v/v was identified by a graphical optimization technique using an overlay plot. While using this optimized condition all analytes were baseline resolved in <10 min. Solvent mixtures were delivered at 1.5 mL/min flow rate and analytes peaks were detected at 222 nm. The proposed bioanalytical method was validated according to US Food and Drug Administration guidelines. The proposed method was sensitive with detection limits of 0.06-0.15 µg/mL in serum and urine samples. Relative standard deviation for inter- and intra-day precision data was found to be <7%. The proposed method may find application in the determination of selected antihistaminic drugs in biological fluids.

Interaction of Approved Drugs with Synaptic Vesicle Protein 2A.

Levetiracetam (LEV) and its recently approved derivative brivaracetam are anti-epileptic drugs with a unique mechanism of action. The synaptic vesicle protein 2A (SV2A) was previously identified as their main target. In the current study, we tested a collection of 500 approved drugs for interaction with the human SV2A protein expressed in Chinese hamster ovary cells. Competition binding studies were performed using cell lysates with high SV2A expression and [3 H]brivaracetam as a radioligand. A hit rate of 3% was obtained, defined as compounds that inhibited radioligand binding by more than 90% at a screening concentration of 20 µM. Subsequent concentration-inhibition curves revealed the antihistaminic prodrug loratadine (Ki = 1.16 µM) and the antimalarial drug quinine (Ki = 2.03 µM) to be the most potent SV2A protein ligands of the investigated drug library. Both compounds were similarly potent as LEV (Ki = 1.74 µM), providing structurally novel scaffolds for SV2A ligands. A pharmacophore model was established, which indicated steric and electronic conformities of brivaracetam with the new SV2A ligands, and preliminary structure-activity relationships were determined. The anti-convulsive effects of the natural product quinine may - at least in part - be explained by interaction with SV2A. Loratadine and quinine represent new lead structures for anti-epileptic drug development.