RESUMO
INTRODUCTION: Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder that presents with a progressive movement disorder along with cognitive and psychiatric problems. It is caused by a Cytosine-adenin-guanine (CAG) expansion in exon 1 of the huntingtin gene which codes for mutant huntingtin (mHTT) that over time accumulates in cells, causing dysfunction and then death through new toxic gain-of-function mechanisms. Autophagy has been shown to be critical for the degradation of diverse intracytoplasmic aggregate-prone proteins that cause neurodegenerative disease, including mHTT. From a screen of a library enriched in approved drugs, felodipine was selected as the most suitable candidate showing strong autophagy-inducing effects in preclinical models of HD. We are, therefore, conducting a trial to assess the safety and tolerability of felodipine in people with early HD. METHODS AND ANALYSIS: FELL-HD is a phase II, single-centre, open-label, dose-finding trial in people with early HD. 18 participants with early clinical features of the disease will be treated with felodipine for 58 weeks, with a further 4-week follow-up. The primary outcome measure is the number of adverse events attributable to felodipine. Exploratory outcomes include additional measures of motor and cognitive function, non-motor symptoms and quality of life scales, as well as peripheral and central disease biomarkers assessed through brain MRI. Analysis of blood and cerebrospinal fluid will also be performed through an associated sample study, FELL HD-s. ETHICS AND DISSEMINATION: The study was approved by the London-Brent Research Ethics Committee (reference 22/LO/0387) and has been accepted by the Medicines and Healthcare products Regulatory Agency for clinical trials authorisation (reference CTA 12854/0256/001-0001). A lay summary of the results of the trial will be uploaded to our research group website which is publicly accessible. A webinar or in-person open day, to present results of the trial to participants and our wider cohort of patients who attend our centre, will be held once the trial is completed. The results of the trial will also be published in scientific journals and presented at national and international conferences. TRIAL REGISTRATION NUMBERS: EudraCT-2021-000897-27, ISRCTN56240656.
Assuntos
Autofagia , Felodipino , Doença de Huntington , Humanos , Doença de Huntington/tratamento farmacológico , Felodipino/administração & dosagem , Felodipino/uso terapêutico , Autofagia/efeitos dos fármacos , Ensaios Clínicos Fase II como Assunto , Adulto , Masculino , Pessoa de Meia-Idade , Feminino , Regulação para Cima/efeitos dos fármacos , Qualidade de VidaRESUMO
Felodipine has proven to be effective as an atherosclerosis therapy because it increases blood flow to the vessel wall. However, the poor solubility, low bioavailability, and hepatic first-pass metabolism of oral felodipine compromise its therapeutic effectiveness. The study's goal is to create a nasal pH-sensitive hydrogel of felodipine-loaded invasomes (IPHFI) that will improve felodipine's release, permeation, bioavailability, and efficacy as a potential diabetes-associated atherosclerosis therapy. According to the pre-formulation study, the felodipine-loaded invasomes formulation composed of phospholipid (3%w/v), cholesterol (0.16%w/v), ethanol (3%v/v) and cineole (1%v/v) was chosen as the optimum formulation. The optimum formulation was characterized in vitro and then mixed with a mixture of chitosan and glyceryl monooleate to make the IPHFI formulation. The IPHFI formulation enhanced the release and permeation of felodipine by 2.99 and 3-fold, respectively. To assess the efficacy and bioavailability of the IPHFI formulation, it was studied in vivo using an experimental atherosclerosis rat model. Compared to oral free felodipine, the nasal administration of the IPHFI formulation increased the bioavailability by 3.37-fold and decreased the serum cholesterol, triglycerides, LDL, and calcification score by 1.56, 1.53, 1.80, and 1.18 ratios, respectively. Thus, nasal IPHFI formulation may represent a promising diabetes-associated atherosclerosis therapy.
Assuntos
Aterosclerose , Disponibilidade Biológica , Liberação Controlada de Fármacos , Felodipino , Felodipino/administração & dosagem , Felodipino/farmacocinética , Felodipino/química , Animais , Aterosclerose/tratamento farmacológico , Masculino , Ratos , Ratos Sprague-Dawley , Hidrogéis/química , Quitosana/química , Bloqueadores dos Canais de Cálcio/farmacocinética , Bloqueadores dos Canais de Cálcio/administração & dosagem , Bloqueadores dos Canais de Cálcio/química , Diabetes Mellitus Experimental/tratamento farmacológico , Concentração de Íons de Hidrogênio , Solubilidade , Fosfolipídeos/química , Complicações do Diabetes/tratamento farmacológico , Colesterol/química , Portadores de Fármacos/químicaRESUMO
Lipid-based drug delivery systems hold immense promise in addressing critical medical needs, from cancer and neurodegenerative diseases to infectious diseases. By encapsulating active pharmaceutical ingredients - ranging from small molecule drugs to proteins and nucleic acids - these nanocarriers enhance treatment efficacy and safety. However, their commercial success faces hurdles, such as the lack of a systematic design approach and the issues related to scalability and reproducibility. This work aims to provide insights into the drug-phospholipid interaction by combining molecular dynamic simulations and thermodynamic modelling techniques. In particular, we have made a connection between the structural properties of the drug-phospholipid system and the physicochemical performance of the drug-loaded liposomal nanoformulations. We have considered two prototypical drugs, felodipine (FEL) and naproxen (NPX), and one model hydrogenated soy phosphatidylcholine (HSPC) bilayer membrane. Molecular dynamic simulations revealed which regions within the phospholipid bilayers are most and least favoured by the drug molecules. NPX tends to reside at the water-phospholipid interface and is characterized by a lower free energy barrier for bilayer membrane permeation. Meanwhile, FEL prefers to sit within the hydrophobic tails of the phospholipids and is characterized by a higher free energy barrier for membrane permeation. Flory-Huggins thermodynamic modelling, small angle X-ray scattering, dynamic light scattering, TEM, and drug release studies of these liposomal nanoformulations confirmed this drug-phospholipid structural difference. The naproxen-phospholipid system has a lower free energy barrier for permeation, higher drug miscibility with the bilayer, larger liposomal nanoparticle size, and faster drug release in the aqueous medium than felodipine. We suggest that this combination of molecular dynamics and thermodynamics approach may offer a new tool for designing and developing lipid-based nanocarriers for unmet medical applications.
Assuntos
Bicamadas Lipídicas , Lipossomos , Simulação de Dinâmica Molecular , Naproxeno , Termodinâmica , Lipossomos/química , Bicamadas Lipídicas/química , Naproxeno/química , Naproxeno/administração & dosagem , Felodipino/química , Felodipino/administração & dosagem , Fosfatidilcolinas/química , Fosfolipídeos/química , Sistemas de Liberação de MedicamentosRESUMO
The use of animal experiments can be minimized with computational models capable of reflecting the simulated environments. One such environment is intestinal fluid and the colloids formed in it. In this study we used molecular dynamics simulations to investigate solubilization patterns for three model drugs (carvedilol, felodipine and probucol) in dog intestinal fluid, a lipid-based formulation, and a mixture of both. We observed morphological transformations that lipids undergo due to the digestion process in the intestinal environment. Further, we evaluated the effect of bile salt concentration and observed the importance of interindividual variability. We applied two methods of estimating solubility enhancement based on the simulated data, of which one was in good qualitative agreement with the experimentally observed solubility enhancement. In addition to the computational simulations, we also measured solubility in i) aspirated dog intestinal fluid samples and ii) simulated canine intestinal fluid in the fasted state, and found there was no statistical difference between the two. Hence, a simplified dissolution medium suitable for in vitro studies provided physiologically relevant data for the systems explored. The computational protocol used in this study, coupled with in vitro studies using simulated intestinal fluids, can serve as a useful prescreening tool in the process of drug delivery strategies development.
Assuntos
Felodipino , Simulação de Dinâmica Molecular , Solubilidade , Cães , Animais , Felodipino/administração & dosagem , Felodipino/farmacocinética , Felodipino/química , Probucol/administração & dosagem , Probucol/farmacocinética , Probucol/química , Carvedilol/administração & dosagem , Carvedilol/farmacocinética , Carvedilol/química , Lipídeos/química , Líquidos Corporais/química , Líquidos Corporais/metabolismo , Ácidos e Sais Biliares/química , Masculino , Secreções Intestinais/químicaRESUMO
This study focuses on the combination of three-dimensional printing (3DP) and amorphous solid dispersion (ASD) technologies for the manufacturing of gastroretentive floating tablets. Employing hot melt extrusion (HME) and fused deposition modeling (FDM), the study investigates the development of drug-loaded filaments and 3D printed (3DP) tablets containing felodipine as model drug and hydroxypropyl methylcellulose (HPMC) as the polymeric carrier. Prior to fabrication, solubility parameter estimation and molecular dynamics simulations were applied to predict drug-polymer interactions, which are crucial for ASD formation. Physical bulk and surface characterization complemented the quality control of both drug-loaded filaments and 3DP tablets. The analysis confirmed a successful amorphous dispersion of felodipine within the polymeric matrix. Furthermore, the low infill percentage and enclosed design of the 3DP tablet allowed for obtaining low-density systems. This structure resulted in buoyancy during the entire drug release process until a complete dissolution of the 3DP tablets (more than 8 h) was attained. The particular design made it possible for a single polymer to achieve a zero-order controlled release of the drug, which is considered the ideal kinetics for a gastroretentive system. Accordingly, this study can be seen as an advancement in ASD formulation for 3DP technology within pharmaceutics.
Assuntos
Liberação Controlada de Fármacos , Felodipino , Derivados da Hipromelose , Impressão Tridimensional , Solubilidade , Comprimidos , Felodipino/química , Felodipino/administração & dosagem , Derivados da Hipromelose/química , Composição de Medicamentos/métodos , Simulação de Dinâmica Molecular , Portadores de Fármacos/química , Preparações de Ação Retardada/química , Química Farmacêutica/métodos , Tecnologia de Extrusão por Fusão a Quente/métodos , Tecnologia Farmacêutica/métodosRESUMO
The solution behavior and membrane transport of multidrug formulations were herein investigated in a biorelevant medium simulating fasted conditions. Amorphous multidrug formulations were prepared by the solvent evaporation method. Combinations of atazanavir (ATV) and ritonavir (RTV) and felodipine (FDN) and indapamide (IPM) were prepared and stabilized by a polymer for studying their dissolution (under non-sink conditions) and membrane transport in fasted state simulated intestinal fluid (FaSSIF). The micellar solubilization by FaSSIF enhanced the amorphous solubility of the drugs to different extents. Similar to buffer, the maximum achievable concentration of drugs in combination was reduced in FaSSIF, but the extent of reduction was affected by the degree of FaSSIF solubilization. Dissolution studies of ATV and IPM revealed that the amorphous solubility of these two drugs was not affected by FaSSIF solubilization. In contrast, RTV was significantly affected by FaSSIF solubilization with a 30% reduction in the maximum achievable concentration upon combination to ATV, compared to 50% reduction in buffer. This positive deviation by FaSSIF solubilization was not reflected in the mass transport-time profiles. Interestingly, FDN concentrations remain constant until the amount of IPM added was over 1000 µg/mL. No decrease in the membrane transport of FDN was observed for a 1:1 M ratio of FDN-IPM combination. This study demonstrates the importance of studying amorphous multidrug formulations under physiologically relevant conditions to obtain insights into the performance of these formulations after oral administration.
Assuntos
Líquidos Corporais/química , Química Farmacêutica/métodos , Administração Oral , Sulfato de Atazanavir/administração & dosagem , Sulfato de Atazanavir/química , Sulfato de Atazanavir/farmacocinética , Membrana Celular/metabolismo , Combinação de Medicamentos , Felodipino/administração & dosagem , Felodipino/química , Felodipino/farmacocinética , Indapamida/administração & dosagem , Indapamida/química , Indapamida/farmacocinética , Intestinos , Membranas Artificiais , Ritonavir/administração & dosagem , Ritonavir/química , Ritonavir/farmacocinética , SolubilidadeRESUMO
Bead coating or fluid-bed coating serves as an auspicious solvent-based amorphous solid dispersion (ASD) manufacturing technique in respect of minimization of potential physical stability issues. However, the impact of solvent selection on the bead coating process and its resulting pellet formulation is, to the best of our knowledge, never investigated before. This study therefore aims to investigate the influence of the solvent on the bead coating process itself (i.e. manufacturability) and on solid-state characteristics of the resulting ASDs coated onto beads. For this purpose, the drug-polymer system felodipine (FEL)-poly(vinylpyrrolidone-co-vinyl acetate) (PVP-VA) was coated onto microcrystalline cellulose (MCC) beads from acetonitrile (ACN), methanol (MeOH), ethanol (EtOH), acetone (Ac), 2-propanol (PrOH), dichloromethane (DCM) and ethyl acetate (EthAc). A drug loading screening approach with bead coating revealed analogous ability to manufacture high drug-loaded ASDs from the different organic solvents. The results show no correlation with crystallization tendency or with equilibrium solubility of the drug in the different solvents, nor with the solvent-dependent drug-polymer miscibility obtained from film casting experiments. Distinct coating morphologies were however observed for PVP-VA and FEL-PVP-VA ASDs deposited onto beads from the various solvents, which is attributed to differences in solvent evaporation kinetics.
Assuntos
Química Farmacêutica/métodos , Portadores de Fármacos/química , Felodipino/administração & dosagem , Solventes/química , Celulose/química , Cristalização , Composição de Medicamentos/métodos , Estabilidade de Medicamentos , Felodipino/química , Polímeros/química , Pirrolidinas/química , Solubilidade , Compostos de Vinila/químicaRESUMO
PURPOSE: Penetration enhancers (PEs) enhancing efficacy depends on two processes: PEs release from patches and action on skin. Compared with their action on skin, PEs release process was poorly understood. Therefore, the purpose of this study was to make a mechanistic understanding of PEs release from acrylic pressure-sensitive adhesive of patches and propose an unconventional enhancement of PEs efficacy. METHODS: PEs efficacy was evaluated both in drug permeation study and drug pharmacokinetic study. Confocal Raman spectroscopy was employed to observe PEs release behavior by mapping PEs dynamic distribution in skin. The mechanism of PEs release behavior was provided from molecular interaction and rheology using FT-IR, molecular docking, molecular dynamic simulation and rheometer, separately. RESULTS: The release behavior of PEs themselves greatly restricted their efficacy. By using PEG 400, an improvement of oleic acid (OA) release behavior was achieved, and the efficacy of OA was significantly enhanced with enhancing ratio (ER) from 2.69 to 4.10 and AUClast from 1574 ± 87 to 2664 ± 249 ng·h/mL, separately. The improvement of OA release behavior was primarily resulted from reduction of the interaction between OA and adhesive, which was caused by other small molecules with a strong ability in forming hydrogen bonds with adhesive. Also, the rigidity of adhesive was a factor in affecting PEs release behavior. CONCLUSIONS: An unconventional passive enhancement of transdermal drug delivery was achieved via improving PEs themselves releasing from acrylic pressure-sensitive adhesive. Graphical abstract Influence of PEs release behavior on drug permeation through skin and molecular mechanism.
Assuntos
Liberação Controlada de Fármacos/fisiologia , Absorção Cutânea/fisiologia , Adesivos/química , Administração Cutânea , Animais , Química Farmacêutica , Sistemas de Liberação de Medicamentos , Ácidos Graxos/química , Felodipino/administração & dosagem , Felodipino/farmacocinética , Masculino , Modelos Moleculares , Simulação de Acoplamento Molecular , Preparações Farmacêuticas/metabolismo , Ratos , Pele/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Adesivo TransdérmicoRESUMO
ABSTRCT Felodipine has been widely used as a poorly water-soluble model drug for various studies to improve its oral bioavailability and in vivo efficacy. In this study, we developed amorphous solid dispersions (ASDs) via spray drying to enhance the bioavailability of felodipine through using natural zein protein as a novel polymeric excipient. The solid state characterization results demonstrated a single glass transition temperature (Tg ) around 128.6 °C and good physical stability post 3 months accelerated study under the condition of 40 °C and 75% relative humidity (RH), which is possibly accounted for the molecular immobilization and hydrogen bonding interactions between felodipine and zein. By combining the in vitro dissolution study with TIM-1 gastrointestinal simulation investigation, it is indicated that felodipine was rapidly released from the ASD in 30 mins, and the supersaturation of felodipine was well maintained over 6 h, which resulted in a significant enhancement of felodipine bioavailability during simulated digestive processes in the upper GI tract. This study suggests that spray drying combined with natural excipient zein is an efficient formulation strategy for the development of ASDs with enhanced aqueous solubility and bioavailability.
Assuntos
Bloqueadores dos Canais de Cálcio/administração & dosagem , Excipientes/química , Felodipino/administração & dosagem , Zeína/química , Disponibilidade Biológica , Bloqueadores dos Canais de Cálcio/química , Bloqueadores dos Canais de Cálcio/farmacocinética , Química Farmacêutica/métodos , Estabilidade de Medicamentos , Armazenamento de Medicamentos , Felodipino/química , Felodipino/farmacocinética , Trato Gastrointestinal/metabolismo , Umidade , Ligação de Hidrogênio , Técnicas In Vitro , Solubilidade , Temperatura , Temperatura de TransiçãoRESUMO
Felodipine (FLD), a dihydropyridine calcium channel blocker with excellent antihypertensive effect, is poorly soluble and undergoes extensive hepatic metabolism, which lead to poor oral bioavailability (about 15%) and limit its clinic application. The goal of this study was to develop solid lipid nanoparticles (SLNs) loading FLD to improve the oral bioavailability. The FLD loaded solid lipid nanoparticles (FLD-SLNs) were prepared by the effervescent dispersion technique developed by our laboratory, which might have some advantages over traditional methods. The FLD-SLNs showed desired particle characteristics with particle size (198.15 ± 1.82 nm), poly dispersity index (0.26 ± 0.02), zeta-potential (- 25.53 ± 0.60 mV), entrapment efficiency (95.65 ± 0.70%), drug loading (2.33 ± 0.10%), and a spherical appearance. Pharmacokinetic results showed that the FLD-SLNs presented 3.17-fold increase in area under the curve (AUC(0-t)) compared with free FLD after oral administration in beagle dogs, which indicated that SLNs prepared using the effervescent dispersion technique can improve the bioavailability of lipophilic drugs like felodipine by enhancement of absorption and reduction first-pass metabolism.
Assuntos
Bloqueadores dos Canais de Cálcio/farmacocinética , Química Farmacêutica/métodos , Felodipino/farmacocinética , Nanopartículas/metabolismo , Administração Oral , Animais , Anti-Hipertensivos/administração & dosagem , Anti-Hipertensivos/síntese química , Anti-Hipertensivos/farmacocinética , Disponibilidade Biológica , Bloqueadores dos Canais de Cálcio/administração & dosagem , Bloqueadores dos Canais de Cálcio/síntese química , Estudos Cross-Over , Cães , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/síntese química , Portadores de Fármacos/farmacocinética , Felodipino/administração & dosagem , Felodipino/síntese química , Lipídeos , Masculino , Nanopartículas/administração & dosagem , Nanopartículas/química , Tamanho da Partícula , Distribuição AleatóriaRESUMO
OBJECTIVE: Severity of coeliac disease depends in part on the extent of small intestinal mucosa injury. Patients with the most abnormal pathology have loss of duodenal villi CYP3A4, a drug-metabolising enzyme that inactivates many drugs. These patients are hypothesised to have greater systemic concentrations of felodipine, a drug which normally has low oral bioavailability secondary to intestinal CYP3A4-mediated metabolism. It serves as a representative for a class containing many medications. DESIGN: A phase I, open-label, single-dose, pharmacokinetic study. SETTING: London, Ontario, Canada. PARTICIPANTS: Patients with coeliac disease (n=47) with positive serology and healthy individuals (n=68). MAIN OUTCOME MEASURES: Patients with coeliac disease-upper gastrointestinal endoscopy and oral felodipine pharmacokinetics study within a 3-week period. Healthy individuals-oral felodipine pharmacokinetics study with water and grapefruit juice. RESULTS: Coeliac stratification categories: Group A (n=15, normal), B+C (n=16, intraepithelial lymphocytosis with/without mild villous blunting) and D (n=16, moderate/severe villous blunting). Groups A, B+C and D had linear trends of increasing felodipine AUC0-8; mean±SEM, 14.4±2.1, 17.6±2.8, 25.7±5.0; p<0.05) and Cmax (3.5±0.5, 4.0±0.6, 6.4±1.1; p<0.02), respectively. Healthy subjects receiving water had lower felodipine AUC0-8 (11.9±0.9 vs 26.9±0.9, p=0.0001) and Cmax (2.9±0.2 vs 7.7±0.2, p=0.0001) relative to those receiving grapefruit juice. CONCLUSIONS: Increased felodipine concentrations in patients with coeliac disease were most probably secondary to decreased small intestinal CYP3A4 expression. Patients with severe coeliac disease and healthy individuals with grapefruit juice had equivalently enhanced effect. Thus, patients with severe coeliac disease would probably experience similarly altered drug response, including overdose toxicity, from many important medications known to be metabolised by CYP3A4. Patients with coeliac disease with severe disease should be considered for other clinical drug management, particularly when there is the potential for serious drug toxicity.
Assuntos
Doença Celíaca/tratamento farmacológico , Felodipino/farmacocinética , Adulto , Idoso , Doença Celíaca/metabolismo , Citrus paradisi/efeitos adversos , Estudos Cross-Over , Citocromo P-450 CYP3A/metabolismo , Relação Dose-Resposta a Droga , Felodipino/administração & dosagem , Felodipino/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Índice de Gravidade de Doença , Adulto JovemRESUMO
The nano-particulate system for oral delivery faces a big challenge across the gastrointestinal bio-barriers. The aim was to explore the potential applications of bile acid transporter mediated the self-assembled hybrid nanoparticles (SHNPs) of sodium taurocholate (STC) and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol (Soluplus) for augmenting the oral delivery of poorly water-soluble drugs. Felodipine (FLDP) was chosen as a model drug. The self-assembly of STC with Soluplus to load FLDP and the microstructure of the SHNPs were confirmed using molecular simulation, STC determination by high performance liquid chromatography (HPLC) and transmission electron microscope. Results showed that STC was integrated with Soluplus on the surface of nanoparticles by hydrophobic interactions. The permeability of FLDP loaded STC/Soluplus SHNPs was STC dependent in the ileum, which was inhibited by the higher concentrations of STC and the inhibitor of apical sodium-dependent bile acid transporter (ASBT). STC/Soluplus (1:9) SHNPs significantly improved the drug loading of FLDP, achieved the highest permeability of FLDP and realized 1.6-fold of the area under the curve (AUC) of Soluplus self-assembled nanoparticles (SNPs). A water-quenching fluorescent probe P4 was loaded into the STC/Soluplus SHNPs, which verified that the SHNPs were transferred intactly across the ileum. In conclusion, STC/Soluplus SHNPs via ASBT are a potential strategy for enhancing the oral bioavailability of poorly water-soluble drugs.
Assuntos
Portadores de Fármacos/química , Felodipino/administração & dosagem , Nanopartículas/química , Transportadores de Ânions Orgânicos Dependentes de Sódio/química , Simportadores/química , Ácido Taurocólico/química , Administração Oral , Animais , Área Sob a Curva , Composição de Medicamentos/métodos , Liberação Controlada de Fármacos , Felodipino/farmacocinética , Interações Hidrofóbicas e Hidrofílicas , Masculino , Camundongos , Permeabilidade , Polietilenoglicóis/química , Polivinil/química , RatosRESUMO
BACKGROUND: Calcium channel blockers may ameliorate the decline in renal function caused by calcineurin inhibitors in lung transplantation (LTX) recipients. We hypothesized that pre-operative and 12-week post-operative treatment with the calcium channel blocker felodipine would reduce the decline in glomerular filtration rate (GFR). METHODS: In this prospective, randomized, double-blind trial, 39 LTX recipients were transplanted and received placebo (nâ¯=â¯19; GFR, 102 ml/min/1.73 m2 [range, 91-113 ml/min/1.73 m2]) or felodipine (nâ¯=â¯20, GFR, 96 ml/min/1.73 m2 [range, 88-104 ml/min/1.73 m2]). Pre-operative treatment was titrated post-operatively to 10 mg or the maximum tolerable dose. The primary end-point was the change in GFR using Cr-51-labeled EDTA from LTX to 12 weeks thereafter, and follow-up was 52 weeks. RESULTS: The treatment group showed an absolute mean decline in GFR of 31 ml/min/1.73 m2 (95% CI: -40 to 22 ml/min/1.73 m2), whereas that of the placebo group was 48 ml/min/1.73 m2 (95% confidence interval [CI]: -56 to 40 ml/min/1.73 m2). Thus, the difference between groups at 12 weeks was 17 ml/min/1.73 m2 (95% CI: 4-29 ml/min/1.73 m2; pâ¯=â¯0.01). Half of the patients were unable to complete the 3-month primary follow-up, and the analysis includes these patients by intention-to-treat. After 52 weeks (40 weeks after termination of treatment), the treatment effect was maintained at 12 ml/min/1.73 m2 (95% CI: 0-24 ml/min/1.73 m2, pâ¯=â¯0.05). The number of days with registered hypotension was significantly higher in the felodipine group than in the placebo group (39 days vs 13 days, rate ratio: 2.9 [95% CI: 1.5-5.3]). CONCLUSIONS: Use of felodipine in select patients was associated with greater preservation in renal function early (90 days) after LTX. The observed benefits were attenuated by 1 year, although trends in better renal function were noted.
Assuntos
Pressão Sanguínea/fisiologia , Felodipino/administração & dosagem , Taxa de Filtração Glomerular/efeitos dos fármacos , Rim/fisiopatologia , Transplante de Pulmão , Bloqueadores dos Canais de Cálcio/administração & dosagem , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos ProspectivosRESUMO
Advanced drug delivery systems (ADDS) are widely explored to overcome poor aqueous solubility of orally administered drugs. However, the prediction of their in vivo performance is challenging, as in vitro models typically do not capture the interplay between processes occurring in the gut. In additions, different models are used to evaluate the different systems. We therefore present a method that allows monitoring of luminal processing (dissolution, digestion) and its interplay with permeation to better inform on the absorption of felodipine formulated as ADDS. Experiments were performed in a µFLUX-apparatus, consisting of two chambers, representing the intestinal and serosal compartment, separated by Caco-2 monolayers. During dissolution-digestion-permeation experiments, ADDS were added to the donor compartment containing simulated intestinal fluid and immobilized lipase. Dissolution and permeation in both compartments were monitored using in situ UV-probes or, when turbidity interfered the measurements, with HPLC analysis. The method showed that all ADDS increased donor and receiver concentrations compared to the condition using crystalline felodipine. A poor correlation between the compartments indicated the need for an serosal compartment to evaluate drug absorption from ADDS. The method enables medium-throughput assessment of: (i) dynamic processes occurring in the small intestine, and (ii) drug concentrations in real-time.
Assuntos
Química Farmacêutica , Sistemas de Liberação de Medicamentos , Felodipino/administração & dosagem , Absorção Intestinal , Administração Oral , Células CACO-2 , Cristalização , Felodipino/química , Felodipino/farmacocinética , Humanos , SolubilidadeRESUMO
The antihypertensive drug felodipine (FD) is a typical biopharmaceutics classification system (BCS) II drug; thus, improving the dissolution rate of FD is very important to enhance its bioavailability. Besides, according to the in situ "close loop" perfusion assay, we found that the jejunum is the main absorptive site, then the duodenum and ileum. Consequently, a novel micron-size particulate of FD in a core-shell structure was fabricated by a coaxial electrospray technique; within the drug delivery system, Hypromellose K4M (HPMC K4M) was selected as a sheath material to prolong the retention time in the upper GI tract, while povidone K30 (PVP K30) was mixed with FD in the inner layer. The dissolution study in three different media (0.02% Tween-80 solution; phosphate buffer containing 0.02% Tween-80, pH 6.8; and HCl solution containing 0.02% Tween-80, pH 1.2) demonstrated that FD-loaded coaxial electrospray particles (F-COES) could greatly improve the dissolution of FD. Furthermore, in vivo pharmacokinetics revealed that F-COES emerged no changes in the half-life but significantly prolonged the tmax and increased the oral bioavailability. Collectively, this work supplies a promising drug release system that will improve the dissolution and enhance the bioavailability simultaneously for those poorly water-soluble drugs mainly absorbed in the upper GI tract.
Assuntos
Anti-Hipertensivos/administração & dosagem , Anti-Hipertensivos/farmacocinética , Felodipino/administração & dosagem , Felodipino/farmacocinética , Administração Oral , Animais , Anti-Hipertensivos/química , Disponibilidade Biológica , Sistemas de Liberação de Medicamentos , Felodipino/química , Técnicas In Vitro , Intestino Delgado/metabolismo , Masculino , Tamanho da Partícula , Polissorbatos , Ratos Sprague-Dawley , SolubilidadeRESUMO
The fluidity of vesicular membrane affects vesicular transdermal drug delivery. Essential oils can be located in vesicular membrane imparting flexibility and influencing transdermal delivery. Accordingly, the objective was to investigate the effect of incorporation of essential oils in niosomes on felodipine transdermal delivery. Rigid niosomes comprising Span 60 with cholesterol (2:1, w/w) were used with clove, eucalyptus or lemon oils being incorporated in the vesicles at increasing concentrations. The vesicle size and shape was monitored using scanning electron microscopy. Thermal analysis was used to monitor the thermal behavior. Drug entrapment efficiency, release and skin permeation were monitored. Niosomes were spherical with size ranging from 279 to 345 nm. The drug entrapment ranged from 97.9 to 98.8%. Thermal analysis confirmed the existence of oils within vesicular membrane and highlighted the membrane fluidizing effect. Drug release depended on the oil with clove oil or eucalyptus oil showing a trend of increased drug release compared with plain niosomes. In contrast, lemon oil reduced drug release rate. Skin permeation study reflected the superiority of oil containing niosomes. The results correlated with the fluidizing and penetration enhancing effects of oils. The study introduced essential oils as potential niosomes fluidizing agents for enhanced transdermal drug delivery.
Assuntos
Felodipino/administração & dosagem , Felodipino/química , Lipossomos/química , Óleos Voláteis/química , Administração Cutânea , Animais , Sistemas de Liberação de Medicamentos/métodos , Masculino , Microscopia Eletrônica de Varredura/métodos , Tamanho da Partícula , Coelhos , Pele/metabolismo , Absorção CutâneaRESUMO
The oral cavity is of great importance to the performance of orally retained formulations, including: orally disintegrating tablets, taste-masked formulations, and buccal/sublingual delivery systems. With regards to in vitro dissolution assessment of these dosage forms, human saliva should be represented by the dissolution media. Currently there is no general consensus regarding oral cavity dissolution. In this study pooled human saliva was characterised and utilised as dissolution media for biorelevant oral cavity dissolution studies and to assess drug release. Lipophilic drug felodipine with challenging biopharmaceutical properties was selected for assessment in oral cavity dissolution studies. These saliva dissolution studies investigated for the first time how biorelevant dissolution can be implemented as a screening tool to guide the formulation development process and to predict dosage form performance within the mouth. In this study a combination of three dissolution enhancement strategies (cryomilling, solid dispersion, and inclusion complexation) were employed to eventually increase the concentration of felodipine in saliva 150-fold. Using this successful formulation strategy orally disintegrating tablets of felodipine were produced. Interestingly, the percentage release of felodipine in compendial dissolution apparatus was shown to be over 80% after 10â¯min. On the other hand, saliva-based dissolution showed that percentage release of felodipine was only 0.2% after 10â¯min using the same formulation. This discrepancy in drug release between dissolution media highlights the need for biorelevant dissolution apparatus for the oral cavity to reliably assess performance of relevant dosage forms in vitro.
Assuntos
Bloqueadores dos Canais de Cálcio/administração & dosagem , Sistemas de Liberação de Medicamentos , Felodipino/administração & dosagem , Saliva/metabolismo , Administração Oral , Bloqueadores dos Canais de Cálcio/química , Bloqueadores dos Canais de Cálcio/metabolismo , Química Farmacêutica/métodos , Liberação Controlada de Fármacos , Felodipino/química , Felodipino/metabolismo , Humanos , Solubilidade , ComprimidosRESUMO
Water is often readily absorbed by amorphous compounds, lowering their glass transition temperature (Tg) and facilitating their recrystallization (via nucleation-and-growth). At the same time, the increase in moisture content translates to a decrease in both the thermodynamic solubility and intrinsic dissolution rate, as compared to the corresponding dry (pure) amorphous phase, e.g. see [Murdande SB, Pikal MJ, Shanker RM, Bogner RH. 2010. Solubility advantage of amorphous pharmaceuticals: I. A thermodynamic analysis. J Pharm Sci 99:1254-1264.]. In the case of pure indomethacin and felodipine, the solubility advantage of each amorphous phase over its crystalline counterpart were previously determined to be 7.6 and 4.7, respectively, using a new methodology together with basic calorimetric data taken from the literature. Herein, we demonstrate that, theoretically, following the uptake of just â¼0.5% w/w water, the solubility ratios decrease to 6.9 and 4.5, in the same order. Moreover, as the predicted intrinsic dissolution rate (based on the Noyes-Whitney equation) is directly proportional to the solubility advantage of a given amorphous-crystalline pair, it decreases proportionately upon moisture uptake. Applying the methodology presented herein, one can directly predict the extent of Tg-lowering observed at any moisture content, for a given amorphous phase. Knowing that value, it is possible to estimate the relative decrease in the solubility and/or intrinsic dissolution rate of the plasticized phase compared to the pure glass, and vice-versa.
Assuntos
Química Farmacêutica/métodos , Felodipino/administração & dosagem , Indometacina/administração & dosagem , Água/química , Calorimetria/métodos , Cristalização , Liberação Controlada de Fármacos , Felodipino/química , Indometacina/química , Solubilidade , Termodinâmica , Temperatura de Transição , VitrificaçãoRESUMO
Felodipine has a very low bioavailability due to first-pass metabolism. The aim of this study was to enhance its bioavailability by transdermal application. Felodipine-loaded transferosomes were prepared by thin-film hydration using different formulation variables. An optimized formula was designed using statistical experimental design. The independent variables were the used edge activator, its molar ratio to phosphatidylcholine, and presence or absence of cholesterol. The responses were entrapment efficiency of transferosomes, their size, polydispersity index, zeta potential, and percent drug released after 8 h. The optimized formula was subjected to differential scanning calorimetry studies and its stability on storage at 4°C for 6 months was estimated. This formula was improved by incorporation of different permeation enhancers where ex vivo drug flux through mice skin was estimated and the best improved formula was formulated in a gel and lyophilized. The prepared gel was subjected to in vivo study using Plendil® tablets as a reference. According to the calculated desirability, the optimized transferosome formula was that containing sodium deoxycholate as edge activator at 5:1 M ratio to phosphatidylcholine and no cholesterol. The thermograms of this formula indicated the incorporation of felodipine inside the prepared vesicles. None of the tested parameters differed significantly on storage. The lyophilized gel of labrasol-containing formula was chosen for in vivo study. The relative bioavailability of felodipine from the designed gel was 1.7. In conclusion, topically applied lyophilized gel containing felodipine-loaded transferosomes is a promising transdermal delivery system to enhance its bioavailability.
Assuntos
Sistemas de Liberação de Medicamentos/métodos , Felodipino/administração & dosagem , Géis/administração & dosagem , Absorção Cutânea/efeitos dos fármacos , Administração Cutânea , Animais , Animais Recém-Nascidos , Disponibilidade Biológica , Varredura Diferencial de Calorimetria , Felodipino/química , Felodipino/metabolismo , Liofilização , Géis/química , Géis/metabolismo , Lecitinas/administração & dosagem , Lecitinas/química , Lecitinas/metabolismo , Lipossomos , Camundongos , Absorção Cutânea/fisiologia , Comprimidos , Adesivo TransdérmicoRESUMO
The oral bioavailability of felodipine (FEL) is very low, i.e., about 15%. This could be due to low water solubility and hepatic first-pass effect. The objective of the present study was to develop FEL microemulsion-based gel, to bypass the first pass effect, for buccal delivery. The optimized FEL microemulsion (OPT-MEF) was used to prepare buccoadhesive gels, with varying concentrations of hydroxypropyl methylcellulose (HPMC) E4M and polycarbophil (PCP), and evaluated. The cross-linking of the PCP gelling agent was done by adjusting the pH with a neutralizing agent, triethanolamine (TEA). The formulations, namely drug suspension, OPT-MEF, microemulsion-based buccal gel containing 1% w/v (MEF-E4M1), 2% w/v (MEF-E4M2), and 3% w/v (MEF-E4M3) of HPMC K4M and 1% w/v (MEF-PCP1), 2% w/v (MEF-PCP2), and 3% w/v (MEF-PCP3) of PCP were prepared and optimized on the basis of ex vivo permeation study, mucoadhesion force, and viscosity. The optimized buccal gel (MEF-PCP1) showed significantly higher (p < 0.01) permeation flux (J = 0.44 ± 0.16 mg/cm2/h), when compared with the drug suspension (J = 0.17 ± 0.14 mg/cm2/h). The permeation enhancement ratio of MEF-PCP1 was found to be 2.59 times higher than that of the aqueous suspension of the drug. The texture profile analysis of MEF-PCP1 was performed which showed spreadability (3.2 mJ), extrudability (151.8 mJ), hardness (13.8 g), and adhesiveness (41.0 g), and results indicated good spreadability and adhesiveness. The rheological study revealed the pseudoplastic flow behavior of MEF-PCP1 buccal gel. The Cmax value 9.21 ± 2.88 µg/ml of MEF-PCP1 gel was found to be significantly higher (P < 0.01) compared to the same dose administered by oral route (Cmax value 3.51 ± 1.74 µg/ml). The relative bioavailability (Fr) of the optimized MEF-PCP1 buccal gel was about 397.39% higher than that of oral route. In conclusion, consistent and effective buccal gel containing optimized FEL-loaded microemulsion, with improved buccal permeation and pharmacokinetic parameters was developed successfully to improve the bioavailability of FEL.