Physicochemical characterisation and cyclodextrin complexation of erlotinib

Engineering of Amphiphilic Erlotinib Analogue as Novel Nanomedicine for Non-Small Cell Lung Cancer Therapy

Purpose

Molecular targeted therapy is one of the most pivotal strategies in the treatment of non-small cell lung cancer, yet its curative effect is severely compromised by the poor aqueous solubility, low bioavailability and inadequate tumor accumulation of targeted agents. To enhance the efficacy of targeted agents, we demonstrate a novel self-assemble amphiphilic molecule based on erlotinib as an effective nanodrug for anti-cancer treatment.

Methods

An amphiphilic molecule composed of hydrophobic erlotinib and hydrophilic biotin block was synthesized and characterized by nuclear magnetic resonance (NMR) as well as high-resolution mass spectrometry (HRMS). Then, nanoassemblies of the amphiphilic molecules are formulated by using nanoprecipitation method. Subsequently, the size, morphology, cell uptake, the anticancer activity and in vivo distribution of the newly constructed erlotinib nanodrug were systematically assessed by some methods, including transmission electron microscopy (TEM), dynamic light-scattering (DLS), flow cytometry, in vivo imaging system etc.

Results

We developed a novel nanoformulation of erlotinib, which possesses a high drug loading of 45%. With the features of well-defined structure and small size, the obtained nanodrug could be effectively accumulated in tumor sites and rapidly internalized by cancer cells. Finally, the erlotinib-based nanoformulation showed considerably better anticancer activity compared to free erlotinib both in vitro and in vivo. Moreover, the nanodrug displayed great tolerability.

Conclusion

Combining the advantageous features of both nanotechnology and self-assemble, this novel erlotinib nanomedicine constitutes a promising therapeutic candidate for cancer treatment. This study also underlines the potential use of amphiphilic molecule for improving drug efficacy as well as reducing drug toxicity, which could become a general strategy for the preparation of nanodrugs of active agents.

Cyclodextrin Inclusion Complexes for Improved Drug Bioavailability and Activity: Synthetic and Analytical Aspects

Many active pharmaceutical ingredients show low oral bioavailability due to factors such as poor solubility and physical and chemical instability. The formation of inclusion complexes with cyclodextrins, as well as cyclodextrin-based polymers, nanosponges, and nanofibers, is a valuable tool to improve the oral bioavailability of many drugs. The microencapsulation process modifies key properties of the included drugs including volatility, dissolution rate, bioavailability, and bioactivity. In this context, we present relevant examples of the stabilization of labile drugs through the encapsulation in cyclodextrins. The formation of inclusion complexes with drugs belonging to class IV in the biopharmaceutical classification system as an effective solution to increase their bioavailability is also discussed. The stabilization and improvement in nutraceuticals used as food supplements, which often have low intestinal absorption due to their poor solubility, is also considered. Cyclodextrin-based nanofibers, which are polymer-free and can be generated using environmentally friendly technologies, lead to dramatic bioavailability enhancements. The synthesis of chemically modified cyclodextrins, polymers, and nanosponges based on cyclodextrins is discussed. Analytical techniques that allow the characterization and verification of the formation of true inclusion complexes are also considered, taking into account the differences in the procedures for the formation of inclusion complexes in solution and in the solid state.

Profound effects of gastric secretion rate variations on the precipitation of erlotinib in duodenum - an in vitro investigation

Using an artificial stomach and duodenum (ASD), we investigated the pH-dependent precipitation of erlotinib (ERL) during dissolution in the gastrointestinal (GI) tract by varying the rate of gastric fluid secretion (GFS). Results show that decreasing GFS rate from 2.5 to 0.5 mL/min leads to an increased degree of supersaturation in the duodenum fluid due to elevated pH, resulting in precipitation of ERL and a reduced area under the curve (AUC) of the concentration - time profiles from 14,000 to 3,000 (μg‧min)/mL. Such a change in AUC is expected to lower the bioavailability of ERL, a BCS II drug, in patients with a low GFS. This example demonstrates the potential use of ASD as an effective tool for guiding the efficient development of robust tablet formulations by better understanding the impact of GI tract pH on the fate of drugs in the duodenal fluid.

Membrane-camouflaged supramolecular nanoparticles for co-delivery of chemotherapeutic and molecular-targeted drugs with siRNA against patient-derived pancreatic carcinoma

Pancreatic cancer remains one of the most lethal malignancies worldwide. The combination of the first-line standard agent gemcitabine (GEM) with the molecular-targeted drug erlotinib (Er) has emerged as a promising strategy for pancreatic cancer treatment. However, the clinical benefit from this combination is still far from satisfactory due to the unfavorable drug antagonism and the fibrotic tumor microenvironment. Herein, we propose a membrane-camouflaged dual stimuli-responsive delivery system for the co-delivery of GEM and Er into pancreatic cancer cells and tissues to block the antagonism, as well as reshapes profibrotic tumor microenvironment via simultaneous delivery of small interference RNA (siRNA) for synergistic pancreatic cancer treatment. This “all-in-one” delivery system exhibits sensitive GSH and pH-dependent drug release profiles and enhances the inhibitory effects on the proliferation and migration of tumor cells in vitro. Excitingly, the systemic injection of such a biomimetic drug co-delivery system not only resulted in superior inhibitory effects against orthotopic pancreatic tumor and patient-derived tumor (PDX), but also greatly extended the survival rate of tumor-bearing mice. Our findings provide a promising therapeutic strategy against pancreatic cancer through the enhanced synergistic effect of target therapy, chemotherapy and anti-fibrotic therapy, which represents an appealing way for pancreatic cancer treatment.

Topical noninvasive retinal drug delivery of a tyrosine kinase inhibitor: 3% cediranib maleate cyclodextrin nanoparticle eye drops in the rabbit eye

PURPOSE

Tyrosine kinase inhibitors inhibit VEGF receptors. If delivered to the retina, they might inhibit oedema and neovascularization such as in age-related macular degeneration and diabetic retinopathy. The aim of this study was to formulate cediranib maleate, a potent VEGF inhibitor, as γ-cyclodextrin nanoparticle eye drops and measure the retinal delivery and overall ocular pharmacokinetics after a single-dose administration in rabbits.

METHODS

A novel formulation technology with 3% cediranib maleate as γ-cyclodextrin micro-suspension was prepared by autoclaving method. Suitable stabilizers were tested for heat-stable eye drops. The ophthalmic formulation was topically applied to one eye in rabbits. The pharmacokinetics in ocular tissues, tear film and blood samples were studied at 1, 3 and 6 hr after administration.

RESULTS

γ-cyclodextrin formed complex with cediranib maleate. The formation of γ-cyclodextrin nanoparticles occurred in concentrated complexing media. Combined stabilizers prevented the degradation of drug during the autoclaving process. Three hours after administration of the eye drops, treated eyes showed cediranib levels of 737 ± 460 nM (mean ± SD) in the retina and 10 ± 6 nM in the vitreous humour.

CONCLUSIONS

Cediranib maleate in γ-cyclodextrin nanoparticles were stable to heat in presence of stabilizers. The drug as eye drops reached the retina in concentrations that are more than 100 times higher than the 0.4 nM IC₅₀ value reported for the VEGF type-II receptor and thus, presumably, above therapeutic level. These results suggest that γ-cyclodextrin-based cediranib maleate eye drops deliver effective drug concentrations to the retina in rabbits after a single-dose administration.

A novel architecture for achieving high drug loading in amorphous spray dried dispersion tablets

Although Amorphous Solid Dispersions (ASDs) effectively increase bioavailability, tablet mass can be high due to the large fraction of excipients needed to stabilize the amorphous drug in the solid state, extend drug supersaturation in solution and achieve robust manufacturability. The aim of this work was to reduce tablet mass of an ASD tablet comprising a low glass transition temperature (Tg), rapidly crystallizing drug without compromising these key attributes. In this approach, erlotinib (Tg = 42 °C, Tm/Tg = 1.4 K/K) was spray dried with the high Tg polymer poly(methyl methacrylate-co-methacrylic acid) (Eudragit® L100, Evonik) (Tg = 187 °C) to facilitate high drug loading while maintaining physical stability. Hydroxypropyl methylcellulose acetate succinate (HPMCAS) (AQOAT® HF, Shin-Etsu) was granulated with the ASD to extend supersaturation in solution. For comparison, a benchmark ASD was spray dried at a lower drug loading with HPMCAS-H (Tg = 119 °C). This High Loaded Dosage Form (HLDF) approach reduced tablet mass by 40%, demonstrated similar physical stability and in vitro performance as the benchmark and exhibited excellent downstream manufacturability. Strategically combining two different polymers in a tablet to maintain physical stability and sustain supersaturation in solution can decrease tablet mass of some low Tg, rapidly crystallizing amorphous drugs.

Physicochemical Characterization and Cyclodextrin Complexation of the Anticancer Drug Lapatinib

Lapatinib (LAP), the tyrosine kinase inhibitor drug with moderate bioavailability, was characterized in terms of physicochemical properties: acid-base characteristics, lipophilicity, and solubility. The highly lipophilic nature of the drug and its extremely low water solubility (S0=0.82 nM) limit the development of a parenteral formulation. In order to enhance solubility and bioavailability, inclusion complex formation with cyclodextrins (CDs) is a promising method of choice. Therefore, LAP-CD interactions were also studied by a multianalytical approach. The stability constants of LAP with native cyclodextrins, determined by UV spectroscopy, identified the seven-membered β-CD as the most suitable host. Continuous variation method (Job’s plot) by 1H NMR showed a 1 : 1 stoichiometry for the complexes. The geometry of the complex was elucidated by 2D ROESY NMR measurements and molecular modeling, indicating that the partial molecular encapsulation includes the fluorophenyl ring of LAP. Phase-solubility studies with four CDs, β-CD, (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD), randomly methylated-β- (RAMEB-) cyclodextrin, and sulfobutylether-β-cyclodextrin (SBE-β-CD), show an AL type diagram and highly increased solubility via CD complexation. The results are especially promising with SBE-β-CD, exerting more than 600-fold gain in solubility. The equilibrium and structural information presented herein can offer the molecular basis for an improved drug formulation with enhanced bioavailability.