RESUMO
Oral delivery of potent peptide drugs provides key formulation challenges in the pharmaceutical industry: stability, solubility, and permeability. Intestinal permeation enhancers (PEs) can overcome the low oral bioavailability by improving the drug permeability. Conventional in vitro and ex vivo models for assessing PEs fail to predict efficacy in vivo. Here, we compared Caco-2 cells cultured in the conventional static Transwell model to a commercially available continuous flow microfluidic Gut-on-a-Chip model. We determined baseline permeability of FITC-Dextan 3 kDa (FD3) in Transwell (5.3 ± 0.8 × 10-8 cm/s) vs Chip (3.2 ± 1.8 × 10-7 cm/s). We screened the concentration impact of two established PEs sodium caprate and sucrose monolaurate and indicated a requirement for higher enhancer concentration in the Chip model to elicit equivalent efficacy e.g., 10 mM sodium caprate in Transwells vs 25 mM in Chips. Fasted and fed state simulated intestinal fluids (FaSSIF/FeSSIF) were introduced into the Chip and increased basal FD3 permeability by 3-fold and 20-fold, respectively, compared to 4-fold and 4000-fold in Transwells. We assessed the utility of this model to peptides (Insulin and Octreotide) with PEs and observed much more modest permeability enhancement in the Chip model in line with observations in ex vivo and in vivo preclinical models. These data indicate that microfluidic Chip models are well suited to bridge the gap between conventional in vitro and in vivo models.
Assuntos
Absorção Intestinal , Peptídeos , Permeabilidade , Células CACO-2 , Humanos , Peptídeos/química , Absorção Intestinal/efeitos dos fármacos , Administração Oral , Dispositivos Lab-On-A-Chip , Ácidos Decanoicos/química , Disponibilidade Biológica , Sacarose/química , Mucosa Intestinal/metabolismo , Mucosa Intestinal/efeitos dos fármacos , Solubilidade , Composição de Medicamentos/métodosRESUMO
Administration of long-acting injectable suspensions is an increasingly common approach to increasing patient compliance and improving therapeutic efficacy through less frequent dosing. While several long-acting suspensions have recently been marketed, parameters modulating drug absorption from suspension-based formulations are not well understood. Further, methods for predicting clinical pharmacokinetic data from preclinical studies are not well established. Together, these limitations hamper compound selection, formulation design and formulation selection through heavy reliance on iterative optimization in preclinical and clinical studies. This article identifies key parameters influencing absorption from suspension-based formulations through compilation and analysis of preclinical and clinical pharmacokinetic data of seven compounds marketed as suspensions; achievable margins for predicting the clinical dose and input rate from preclinical studies as a function of the preclinical species, the clinical injection location and the intended therapeutic duration were also established.
Assuntos
Suspensões , Humanos , Estudos Retrospectivos , InjeçõesRESUMO
PURPOSE: In this study we evaluated the utility of in-vitro screening tools for predicting the in-vivo behavior of six cyclic peptides with different solubility and permeability properties (BCS class II and III), intended for oral delivery in presence of permeation enhancer Labrasol. METHODS: An in vitro flux assay was used to assess peptide permeation across a biomimetic, lipid-based membrane and in vivo studies in rats were used to determine oral peptide bioavailability in the presence of Labrasol. RESULTS: The in vitro flux was significantly increased for BCS class III peptides, while it significantly decreased or remained unchanged for BCS class II peptides with increasing Labrasol concentrations. The different flux responses were attributed to the combination of reduced effective free peptide concentration and increased membrane permeability in the presence of Labrasol. In vivo studies in male Wistar-Hans rats indicated improved oral bioavailability at different extents for all peptides in presence of Labrasol. On comparing the in vitro and in vivo data, a potential direct correlation for BCS class III peptides was seen but not for BCS class II peptides, due to lower free concentrations of peptides in this class. CONCLUSION: This study assessed the utility of in vitro screening tools for selecting peptides and permeation excipients early in drug product development. Graphical Abstract Graphical Abstract and Figure 1 contains small text.Graphical Abstract text is made larger. The Figure 1 text cannot be made larger.
Assuntos
Peptídeos Cíclicos/administração & dosagem , Peptídeos Cíclicos/farmacocinética , Administração Oral , Animais , Disponibilidade Biológica , Permeabilidade da Membrana Celular , Química Farmacêutica , Excipientes/química , Glicerídeos/química , Bicamadas Lipídicas/metabolismo , Masculino , Modelos Biológicos , Peptídeos Cíclicos/química , Ratos Wistar , SolubilidadeRESUMO
The purpose of this research was to assess variability in pharmacokinetic profiles (PK variability) in preclinical species and identify the risk factors associated with the properties of a drug molecule that contribute to the variability. Exposure data in mouse, rat, dog, and monkey for a total of 16,592 research compounds studied between 1999 and 2013 were included in the analysis. Both in vivo study parameters and in silico/experimental physicochemical properties of the molecules were analyzed. Areas under the plasma concentration vs time curves (AUC) were used to assess PK variability. PK variability was calculated as the ratio of the highest AUC within a defined set of AUC values (AUCmax) over the lowest AUC within that set (AUCmin). Both intra- and inter-animal variability were analyzed, with intra-animal exposures found to be more variable than inter-animal exposures. While several routes of administration were initially studied, the analysis was focused on the oral route, which corresponds to the large majority of data points and displays higher variability than the subcutaneous, intraperitoneal, or intravenous routes. The association between inter-animal PK variability and physical properties was studied, and low solubility, high administered dose, high preclinical dose number (PDo), and pH-dependent solubility were found to be associated with high variability in exposures. Permeability-as assessed by the measured permeability coefficient in the LLC-PK1 cell line-was also considered but appeared to only have a weak association with variability. Consistent with these findings, BCS class I and III compounds were found to be less prone to PK variability than BCS class II and IV compounds. A modest association of PK variability with clearance was observed while the association with bioavailability, a higher PK variability for compounds with lower bioavailability, appeared to be more pronounced. Finally, two case studies that highlight PK variability issues are described, and successful mitigation strategies are presented.
Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Animais , Área Sob a Curva , Líquidos Corporais/metabolismo , Cães , Humanos , Concentração de Íons de Hidrogênio , Absorção Intestinal/fisiologia , Células LLC-PK1 , Camundongos , Permeabilidade , Preparações Farmacêuticas/metabolismo , Farmacocinética , Ratos , SuínosRESUMO
Despite many documented differences in gut physiology compared to humans, the beagle dog has been successfully used as a preclinical model for assessing the relative bioavailability of dosage forms during formulation development. However, differences in pH and bile salt concentration and micellar structure between dog and human intestinal fluids may influence the solubility and dissolution behavior of especially BCS II/IV compounds. Recently, a canine fasted simulated intestinal fluid (FaSSIFc) mimicking the composition in the lumen of the beagle dog under the fasted state has been proposed. In this manuscript, we present the utilization of FaSSIFc to compare solubility of several preclinical candidates against human FaSSIF. While solubility of free bases and neutral compounds was easily predicted by the relative amounts of sodium taurocholate in the fluids, free acids were shown to be much more soluble in FaSSIFc owing to both the solubility at higher pH as well as the increased bile salt concentration. For one of the model compounds, we demonstrate that the high solubility necessitates the need for a formulation comparison at a relatively higher dose in the dog to mimic the outcome of a human relative bioavailability study. Finally, we show how using the solubility value in FaSSIFc for the same compound results in better predictability of the plasma concentration profiles in dogs from a physiologically based absorption model. The collective data indicate that caution and more detailed measurements are required if the dog is used as the preclinical model for the development of formulations of weak acids.
Assuntos
Mucosa Intestinal/metabolismo , Medição de Risco , Animais , Disponibilidade Biológica , Cães , Composição de Medicamentos , Jejum , Humanos , SolubilidadeRESUMO
Preclinical species are a crucial component of drug development, but critical differences in physiology and anatomy need to be taken into account when attempting to extrapolate to humans or between species. The same is true when trying to develop oral formulations for preclinical species, especially unconventional formulations, such as sustained release tablets. During the evaluation of such specialized dosage forms, dissolution can be a critical in vitro tool used to rank-order formulations and ultimately choose the desired release rate. Here, the development of a canine biorelevant dissolution method for the prediction of the in vivo performance of sustained release matrix tablets in beagle dogs is described. The method accounts for differences in physiology between humans and dogs such as gastrointestinal fluid composition, gastric emptying forces, and gastric residence time. The most critical dissolution method parameters were found to be the paddle speed used to simulate the gastric emptying forces as well as the time spent in simulated gastric fluid. The resulting differences in method conditions are further explored through in silico models of the hydrodynamic forces applied to a dosage form. Two case studies are reported showing that the method was able to obtain excellent in vitro-in vivo relationships (slopes ranging from 1.08-1.01) which are significantly (p < 0.01-0.05) improved compared to human biorelevant dissolution used to predict in vivo performance in humans (slopes â¼1.5-1.75). The quality of the method's predictive ability allows for it to help drive the development of matrix sustained release formulations intended for preclinical studies.
Assuntos
Química Farmacêutica/métodos , Preparações de Ação Retardada/química , Preparações de Ação Retardada/metabolismo , Comprimidos/química , Comprimidos/metabolismo , Administração Oral , Animais , Líquidos Corporais/metabolismo , Simulação por Computador , Cães , Esvaziamento Gástrico/fisiologia , Mucosa Gástrica/metabolismo , Conteúdo Gastrointestinal , Humanos , Modelos Biológicos , SolubilidadeRESUMO
A drug's permeability across biological membranes is a key property associated with the successful development of an orally absorbed drug candidate. Although a variety of methods are available for predicting and assessing permeability, some are more preferred than others at specific stages of drug discovery and development across the pharmaceutical industry. Permeability measurements may be interpreted differently depending on the chosen method. Herein, we present a refreshed perspective on the screening approaches and philosophy in permeability evaluation, from early drug discovery to early clinical development. Additionally, we review and discuss chemical design and drug delivery technologies that can be leveraged to overcome permeability challenges, which are increasingly being used with emerging modalities.
Assuntos
Sistemas de Liberação de Medicamentos , Descoberta de Drogas , Descoberta de Drogas/métodos , Preparações Farmacêuticas/química , Permeabilidade , TecnologiaRESUMO
Medical prescriptions for the alleviation of post-surgical pain are the most abundant source of opioids in circulation. As a systemic drug delivery source, opioids leave patients at high risk for side effects after being dosed. Given the significant rate of unauthorized use, distribution, addiction, and opioid related deaths, an alternative method of post-surgical analgesia is needed. Herein, we report the use of bio-resorbable poly(ester urea) (PEU) films that controllably deliver a non-opioid COX-2 inhibitor, etoricoxib, in vivo and in vitro as a model system for post-surgical pain control. PEU composition, drug-load, and film thickness were varied to selectively control etoricoxib elution. Elution data were fit to a Higuchi model, and the diffusion constant of etoricoxib was calculated in each of the films. Pharmacokinetic (pK) data from an in vivo rat model showed the local tissue concentration of etoricoxib at the study endpoint to be up to 23-fold higher in tissue then plasma. In a well-established mouse model of diabetic neuropathic pain in vivo film implantation showed effective relief of pain for more than 4 days post-implantation and efficacious local etoricoxib delivery. Overall, implementation of local drug delivery systems such as this could reduce the need for opioid prescriptions associated with current pain management strategies.
Assuntos
Ésteres , Ureia , Animais , Inibidores de Ciclo-Oxigenase 2/uso terapêutico , Preparações de Ação Retardada/uso terapêutico , Método Duplo-Cego , Ésteres/uso terapêutico , Etoricoxib/uso terapêutico , Humanos , Camundongos , Dor Pós-Operatória/tratamento farmacológico , Piridinas/uso terapêutico , Ratos , Sulfonas/uso terapêuticoRESUMO
Drug development is a long process which requires careful evaluation of the drug substance (active pharmaceutical ingredient, API), drug product (tablet, capsule etc.) and the bioperformance (both pre-clinical and clinical) before testing the efficacy of the final dosage form. The earliest assessment of a new drug substance requires an understanding of the safety and clinical performance (Phase 1) wherein faster processes (like on-site formulation strategy) have been set in place for quick clinical read-outs. One key gap that exists in this early assessment is the ability to evaluate modified release drug products. Here, an additive manufacturing approach is used to prepare polyvinyl alcohol (PVA) capsule shells using 3D printing (3DP), where the shells can be filled with either a solid or a liquid vehicle containing the API. In this work we demonstrate how we can delay the release of the API from the printed capsules allowing us to evaluate regional absorption in pre-clinical studies. By using 3DP, a new method to provide a series of release profiles is demonstrated, where the induction time of a delayed burst release is controlled by the wall thicknesses of printed capsules. New hanging baskets were also designed and 3D printed for the dissolution tests to better understand the rupturing of these capsules in an USP 2 dissolution apparatus. By controlling the wall thickness of the capsule, the induction time of drug release can be controlled from 12 to 198â¯min. This wide range of induction times demonstrated with this 3DP strategy is not currently available in a commercially available oral drug product form. Varying the induction times to the drug release to interrogate different regions of the GI tract is exhibited in vivo (beagle dogs) and initial analysis suggested a good in vitro/in vivo relationship (IVIVR).
Assuntos
Cápsulas/administração & dosagem , Absorção Intestinal , Impressão Tridimensional , Animais , Fármacos Anti-HIV/administração & dosagem , Fármacos Anti-HIV/química , Cápsulas/química , Carboximetilcelulose Sódica/administração & dosagem , Carboximetilcelulose Sódica/química , Preparações de Ação Retardada/administração & dosagem , Preparações de Ação Retardada/química , Cães , Liberação Controlada de Fármacos , Trato Gastrointestinal/metabolismo , Lamivudina/administração & dosagem , Lamivudina/química , Masculino , Álcool de Polivinil/administração & dosagem , Álcool de Polivinil/químicaRESUMO
Developing new antiretroviral therapies for HIV-1 infection with potential for less frequent dosing represents an important goal within drug discovery. Herein, we present the discovery of ethylâ (1-((4-((4-fluorobenzyl)carbamoyl)-1-methyl-2-(2-(5-methyl- 1,3,4-oxadiazole-2-carboxamido)propan-2-yl)-6-oxo-1,6-dihydropyrimidin-5-yl)oxy)ethyl) carbonate (MK-8970), a highly optimized prodrug of raltegravir (Isentress). Raltegravir is a small molecule HIV integrase strand-transfer inhibitor approved for the treatment of HIV infection with twice-daily administration. Two classes of prodrugs were designed to have enhanced colonic absorption, and derivatives were evaluated in pharmacokinetic studies, both in vitro and in vivo in different species, ultimately leading to the identification of MK-8970 as a suitable candidate for development as an HIV therapeutic with the potential to require less frequent administration while maintaining the favorable efficacy, tolerability, and minimal drug-drug interaction profile of raltegravir.
Assuntos
Inibidores de Integrase de HIV/química , Oxidiazóis/química , Pró-Fármacos/química , Pirimidinonas/química , Pirrolidinonas/química , Acetais/química , Animais , Área Sob a Curva , Carbonatos/química , Cães , Avaliação Pré-Clínica de Medicamentos , Integrase de HIV/química , Integrase de HIV/metabolismo , Inibidores de Integrase de HIV/síntese química , Inibidores de Integrase de HIV/farmacocinética , HIV-1/enzimologia , Meia-Vida , Hepatócitos/metabolismo , Humanos , Mucosa Intestinal/metabolismo , Masculino , Oxidiazóis/síntese química , Oxidiazóis/farmacocinética , Pró-Fármacos/síntese química , Pró-Fármacos/farmacocinética , Pirimidinonas/síntese química , Pirimidinonas/farmacocinética , Curva ROC , Raltegravir Potássico , Ratos , Ratos Wistar , Relação Estrutura-AtividadeRESUMO
Prodrugs can be used to enhance the properties of an active pharmaceutical ingredient or drug, generally by improving solubility and/or permeability of the compound. However, discovery teams duly spend considerable time and resources on structure-activity optimization and formulation-enabled drug delivery technologies to achieve the target exposures and biopharmaceutical properties, when early implementation of prodrugs could lead to an improved drug molecule. The goal of this review is to provide an overview of the achievements during the past few years in developing prodrugs and highlighting the challenges of following this approach.
Assuntos
Sistemas de Liberação de Medicamentos/tendências , Descoberta de Drogas/tendências , Preparações Farmacêuticas/administração & dosagem , Pró-Fármacos/administração & dosagem , Animais , Ensaios Clínicos como Assunto/tendências , Sistemas de Liberação de Medicamentos/métodos , Descoberta de Drogas/métodos , HumanosRESUMO
Prodrugs are chemistry-enabled drug delivery modifications of active molecules designed to enhance their pharmacokinetic, pharmacodynamic and/or biopharmaceutical properties. Ideally, prodrugs are efficiently converted in vivo, through chemical or enzymatic transformations, to the active parent molecule. The goal of this work is to enhance the colonic absorption of a drug molecule with a short half-life via a prodrug approach to deliver sustained plasma exposure and enable once daily (QD) dosing. The compound has poor absorption in the colon and by the addition of a promoiety to block the ionization of the molecule as well as increase lipophilicity, the relative colonic absorption increased from 9% to 40% in the retrograde dog colonic model. A combination of acceptable solubility and stability in the gastrointestinal tract (GI) as well as permeability was used to select suitable prodrugs to optimize colonic absorption.
RESUMO
The biopharmaceutical and physicochemical properties of two new cyclic prodrugs (CA-[cychexalanine (Cha(4)), D-Leu(5) ]-Enkephalin (Enk) and coumarinic acid (CA)-[Cha(4), D-Ala(5)]-Enk) of opioid peptides that were designed to be stable to oxidative metabolism by cytochrome P-450 enzymes in the intestinal mucosa are described in this paper. Two-dimensional nuclear magnetic resonance studies and molecular dynamics simulations showed that these cyclic prodrugs exhibit unique solution conformations (i.e., type I ß-turns), which are favorable for transcellular permeation. The calculated molecular surface areas and cLog P values confirmed that these new cyclic prodrugs are more lipophilic than linear opioid peptides and, thus, they should exhibit better transcellular permeation characteristics. However, Caco-2 cell permeation studies showed that the cyclic prodrugs were substrates for apically polarized efflux transporters (e.g., P-glycoprotein, which significantly limited their transcellular permeation). Permeability studies using an in situ rat intestinal perfusion model confirmed the poor intestinal permeation characteristics of CA-[Cha(4), D-Leu(5) ]-Enk and CA-[Cha(4), D-Ala(5)]-Enk as well as the stability of these two new cyclic prodrugs of opioid peptides to oxidative metabolism. In conclusion, these data clearly show that oral absorption of cyclic prodrugs of opioid peptides can only be achieved by designing molecules devoid of substrate activity for both cytochrome P-450 enzymes and efflux transporters in the intestinal mucosa.
Assuntos
Analgésicos Opioides/metabolismo , Permeabilidade da Membrana Celular , Sistema Enzimático do Citocromo P-450/metabolismo , Desenho de Fármacos , Leucina Encefalina-2-Alanina/metabolismo , Mucosa Intestinal/enzimologia , Pró-Fármacos/metabolismo , Administração Oral , Analgésicos Opioides/administração & dosagem , Analgésicos Opioides/síntese química , Animais , Células CACO-2 , Química Farmacêutica , Estabilidade de Medicamentos , Leucina Encefalina-2-Alanina/administração & dosagem , Leucina Encefalina-2-Alanina/análogos & derivados , Leucina Encefalina-2-Alanina/síntese química , Humanos , Absorção Intestinal , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Conformação Molecular , Simulação de Dinâmica Molecular , Oxirredução , Perfusão , Pró-Fármacos/administração & dosagem , Pró-Fármacos/síntese química , Ratos , Propriedades de Superfície , Tecnologia Farmacêutica/métodosRESUMO
Previously, our laboratory reported that cyclic peptide prodrugs of the opioid peptide H-Tyr-D-Ala-Gly-Phe-D-Leu-OH (DADLE) are metabolized by cytochrome P450 (CYP450) enzymes, which limits their systemic exposure after oral dosing to animals. In an attempt to design more metabolically stable cyclic prodrugs of DADLE, we synthesized analogs of DADLE cyclized with a coumarinic acid linker (CA; CA-DADLE), which contained modifications in the amino acid residues known to be susceptible to CYP450 oxidation. Metabolic stability and metabolite identification studies of CA-DADLE and its analogs were then compared using rat liver microsomes (RLM), guinea pig liver microsomes (GPLM), and human liver microsomes (HLM), as well as recombinant human recombinant cytochrome P450 3A4 (hCYP3A4). Similar to the results observed for CA-DADLE, incubation of its analogs with RLM, GPLM, and HLM resulted in monohydroxylation of an amino acid side chain on these cyclic prodrugs. When CA-DADLE was incubated with hCYP3A4, similar oxidative metabolism of the peptide was observed. In contrast, incubation of the CA-DADLE analogs with hCYP3A4 showed that these amino-acid-modified analogs are not substrates for this CYP450 isozyme. These results suggest that the amino-acid-modified analogs of CA-DADLE prepared in this study could be stable to metabolic oxidation by CYP3A4 expressed in human intestinal mucosal cells.
Assuntos
Analgésicos Opioides/metabolismo , Permeabilidade da Membrana Celular , Sistema Enzimático do Citocromo P-450/metabolismo , Desenho de Fármacos , Leucina Encefalina-2-Alanina/metabolismo , Pró-Fármacos/metabolismo , Analgésicos Opioides/síntese química , Animais , Biotransformação , Química Farmacêutica , Citocromo P-450 CYP3A/metabolismo , Estabilidade de Medicamentos , Leucina Encefalina-2-Alanina/análogos & derivados , Leucina Encefalina-2-Alanina/síntese química , Feminino , Cobaias , Humanos , Hidroxilação , Masculino , Microssomos Hepáticos/enzimologia , Oxirredução , Pró-Fármacos/síntese química , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes/metabolismo , Especificidade por Substrato , Tecnologia Farmacêutica/métodosRESUMO
The objective of this study was to elucidate the role of P-glycoprotein (P-gp) in restricting the blood-brain barrier (BBB) permeation of cyclic prodrugs of the opioid peptide DADLE (H-Tyr-D-Ala-Gly-Phe-D-Leu-OH). The BBB permeation characteristics of these prodrugs and DADLE were determined using an in situ perfused rat brain model and in vitro cell culture model (MDCK-MDR1 cells) of the BBB. The activities of P-gp in these models were characterized using a known substrate (quinidine) and known inhibitors [cyclosporine A (CyA), GF-120918, PSC-833] of P-gp. Cyclic peptide prodrugs exhibited very poor permeation in both models. Inclusion of GF-120918, CyA, or PSC-833 in the brain perfusion medium or the cell culture medium significantly increased the permeation of these cyclic prodrugs. The order of potency of these P-gp inhibitors, as measured using the cyclic prodrugs as substrates, was, by in vitro MDCK-MDR1 cells: GF-120918 = CyA >or= PSC-833; and by in situ rat brain perfusion: GF-120918 > CyA = PSC-833. In conclusion, P-gp in the BBB is the major factor restricting the brain permeation of these cyclic prodrugs. MDCK-MDR1 cells can predict the order of potencies of the investigated P-gp inhibitors to enhance the rat BBB permeation of quinidine and the cyclic prodrugs.