Effects of a ritonavir-containing regimen on the pharmacokinetics of sirolimus or everolimus in healthy adult subjects.

The immunosuppressive agents sirolimus and everolimus are sensitive CYP3A4 substrates with narrow therapeutic index. Ritonavir is a strong CYP3A inhibitor. A phase 1 study was conducted to evaluate the pharmacokinetics, safety, and tolerability of the co-administration of sirolimus or everolimus with the ritonavir-containing 3D regimen of the direct-acting antiviral agents ombitasvir, ritonavir-boosted paritaprevir, and dasabuvir in healthy subjects. This study had two independent arms, each with a two-period, single-sequence, crossover study design. A single dose of sirolimus 2 mg (N = 12) or everolimus 0.75 mg (N = 12) was administered in Period 1. In Period 2, multiple doses of the 3D regimen (ombitasvir/paritaprevir/ritonavir 25/150/100 mg once daily and dasabuvir 250 mg twice daily) were administered for 34 or 28 days, with a single dose of sirolimus 0.5 mg or everolimus 0.75 mg co-administered on Day 15. Following co-administration with the 3D regimen, the sirolimus dose-normalized maximum observed blood concentration (Cmax ) and area under the blood concentration-time curve from time zero to infinity (AUCinf ) increased to 6.4-fold and 38-fold, respectively. Following co-administration with the 3D regimen, the everolimus Cmax and AUCinf increased to 4.7-fold and 27-fold, respectively. Sirolimus and everolimus half-lives increased from 96 to 249 h, and 42 to 118 h, respectively. There were no major safety or tolerability issues in this study. The ritonavir-containing 3D regimen resulted in a significant increase in sirolimus or everolimus exposure, consistent with the known strong inhibitory effect of ritonavir on CYP3A requiring dose and/or frequency modification when co-administered with each other.

A Proposed Approach for the Determination of the Bioequivalence Acceptance Range for Narrow Therapeutic Index Drugs in the European Union.

The current regulatory criterion for bioequivalence of narrow therapeutic index (NTI) drugs in the European Union requires that the 90% confidence interval for the ratio of the population geometric means of the test product compared with the reference for area under the plasma concentration-time curve (AUC), and in certain cases maximum plasma drug concentration (Cmax ), to be included within the tighter acceptance range of 90.00-111.11%. As a consequence, sponsors need to recruit a higher number of subjects to demonstrate bioequivalence and this may be seen as increasing the burden for the development of generics. This "one-size-fits-all" criterion is particularly questionable when the within-subject variability of the reference product is moderate to high. As an alternative, we propose a further refined statistical approach where the acceptance range is narrowed based on the within-subject variability of the reference product of the NTI drug, similar to the one used for widening the standard 80.00-125.00% acceptance range for highly variable drugs. The 80.00-125.00% acceptance range is narrowed, only if the within-subject variability is lower than 30%, down to the current NTI acceptance range of 90.00-111.11% when the within-subject variability is 13.93% or lower. Examples within the current European Medicines Agency list of NTI drugs show a considerable reduction in required sample size for drugs like tacrolimus and colchicine, where the predicted within-subject variability is 20-30%. In these cases, this approach is less sample size demanding without any expected increase in the therapeutic risks, since patients treated with reference products with moderate to high within-subject variability are frequently exposed to bioavailability differences larger than 10%.

Phase I or II Study of Ribociclib in Combination With Topotecan-Temozolomide or Everolimus in Children With Advanced Malignancies: Arms A and B of the AcSé-ESMART Trial.

PURPOSE: AcSé-ESMART is a proof-of-concept, phase I or II, platform trial, designed to explore targeted agents in a molecularly enriched cancer population. Arms A and B aimed to define the recommended phase II dose and activity of the CDK4/6 inhibitor ribociclib with topotecan and temozolomide (TOTEM) or everolimus, respectively, in children with recurrent or refractory malignancies. PATIENTS AND METHODS: Ribociclib was administered orally once daily for 16 days after TOTEM for 5 days (arm A) or for 21 days with everolimus orally once daily continuously in a 28-day cycle (arm B). Dose escalation followed the continuous reassessment method, and activity assessment the Ensign design. Arms were enriched on the basis of molecular alterations in the cell cycle or PI3K/AKT/mTOR pathways. RESULTS: Thirty-two patients were included, 14 in arm A and 18 in arm B, and 31 were treated. Fourteen patients had sarcomas (43.8%), and 13 brain tumors (40.6%). Main toxicities were leukopenia, neutropenia, and lymphopenia. The recommended phase II dose was ribociclib 260 mg/m2 once a day, temozolomide 100 mg/m2 once a day, and topotecan 0.5 mg/m2 once a day (arm A) and ribociclib 175 mg/m2 once a day and everolimus 2.5 mg/m2 once a day (arm B). Pharmacokinetic analyses confirmed the drug-drug interaction of ribociclib on everolimus exposure. Two patients (14.3%) had stable disease as best response in arm A, and seven (41.2%) in arm B, including one patient with T-acute lymphoblastic leukemia with significant blast count reduction. Alterations considered for enrichment were present in 25 patients (81%) and in eight of nine patients with stable disease; the leukemia exhibited CDKN2A/B and PTEN deficiency. CONCLUSION: Ribociclib in combination with TOTEM or everolimus was well-tolerated. The observed activity signals initiated a follow-up study of the ribociclib-everolimus combination in a population enriched with molecular alterations within both pathways.

Exposure-response modeling for extrapolation from adult to pediatric patients who differ with respect to prognostic factors: Application to everolimus.

Pediatric extrapolation is essential for bringing treatments to the pediatric population, especially for indications where the recruitment of pediatric patients into clinical trials is difficult and where fully powered trials are impossible. Often a similar exposure-response relationship between adult and pediatric patients can be assumed, but just matching exposures can be misleading when some prognostic factors for efficacy differ between those two patient populations. We present an example in liver transplantation where different study designs led to different (time-dependent) hazards between populations. Only after accounting for this difference an apparent mismatch between the extrapolation from adults and the pediatric study could be resolved. This article also exemplifies a clear scientific, methodological approach of pediatric extrapolation, including model building in adults, extrapolation to pediatrics, qualification of the extrapolation, and derivation of the actual pediatric efficacy.

Real-world pharmacokinetics and pharmacodynamics of everolimus in metastatic breast cancer.

Purpose This study investigated the relationship between the pharmacokinetics and pharmacodynamics of everolimus in patients with metastatic breast cancer (mBC) in real-world practice.Methods Twenty-two patients with mBC treated with everolimus plus exemestane were enrolled. Blood everolimus concentrations were measured at outpatient visits. The inhibition of the mammalian target of rapamycin (mTOR) activity in peripheral blood mononuclear cells (PBMCs) was examined. The efficacy and safety endpoints were progression-free survival (PFS) and the cumulative incidence of dose-limiting toxicities (DLTs), respectively. Results Blood samples were obtained from 19 consenting patients. Everolimus did not completely inhibit mTOR activity in PBMCs at therapeutic concentrations (~ 56 % maximal inhibition). The most common adverse event was stomatitis (any grade 77 %). The trough concentration (Ctrough) was significantly higher in patients experiencing DLTs than in those without any DLTs (P = 0.030). The optimal Ctrough cutoff predicting DLT development was 17.3 ng/mL. The cumulative incidence of DLTs was significantly higher in patients with Ctrough ≥17.3 ng/mL than in other patients (sub-hazard ratio 4.87, 95 % confidence interval [CI] 1.53-15.5; P = 0.007). Furthermore, the median PFS was numerically longer in patients who maintained a steady-state Ctrough below the threshold than in those who did not (327 days [95 % CI 103-355 days] vs. 194 days [95 % CI 45 days-not estimable]; P = 0.35). Conclusions The suggested upper threshold for the therapeutic window of everolimus Ctrough was 17.3 ng/mL. Pharmacokinetically guided dosing may improve the efficacy and safety of everolimus for mBC, warranting further investigation in a larger study.Clinical trial registry: Not applicable.

Alpelisib in combination with everolimus ± exemestane in solid tumours: Phase Ib randomised, open-label, multicentre study.

BACKGROUND AND PURPOSE: Combined mTORC1 inhibition with everolimus (EVE) and phosphatidylinositol 3-kinase catalytic subunit p110α blockade with alpelisib (ALP) has demonstrated synergistic efficacy in preclinical models and supports testing the combination of ALP and EVE in the clinical setting. The primary objective was to determine the maximum tolerated dose (MTD)/recommended dose for expansion (RDE) of ALP in combination with EVE and in combination with EVE and exemestane (EXE) and subsequently assess safety, preliminary efficacy and effect of ALP on the pharmacokinetics of EVE and determine the magnitude of the drug-drug interaction. PATIENTS AND METHODS: Dose escalation phases were conducted in patients with advanced solid tumours and in postmenopausal women with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC). The dose expansion phase was conducted in patients with pancreatic neuroendocrine tumour and renal cell carcinoma (RCC) (both mechanistic target of rapamycin inhibitor [mTORi]-naive), in patients with mTORi-pretreated solid tumours and in postmenopausal women with HR+, HER2- ABC. RESULTS: During the doublet escalation phase, dose-limiting toxicities (DLTs) were reported in 5 of 10 (50%) patients: one patient had grade (Gr) 2 hyperglycemia and one patient had Gr 3 diarrhoea in the 300 mg dose group, one patient had Gr 2 hyperglycemia and one patient had Gr 4 hypocalcaemia in the 250 mg dose group, and one patient in the 200 mg dose group had Gr 3 diarrhoea and Gr 3 stomatitis. The combination of ALP 250 mg + EVE 2.5 mg was declared as the MTD/RDE in subjects with advanced solid tumours. In the triplet escalation phase, one patient who received ALP 200 mg + EVE 2.5 mg + EXE 25 mg had a DLT of Gr 3 acute kidney injury. This dose combination was declared as the MTD and RDE in subjects with advanced HR-positive HER2-negative BC. The common adverse events (≥30% patients), occurring across all phases, were hyperglycaemia, stomatitis, diarrhoea, nausea, asthenia, decreased appetite and fatigue. The sixteen-week progression-free survival rate was 52.4% (90% confidence interval [CI]: 32.8, 71.4) in the RCC cohort, 35.3% (90% CI: 16.6, 58.0) in the prior pNET cohort and 30.0% (90% CI: 8.7, 60.7) in the prior mTORi cohort. The pharmacokinetics of 2.5 mg of EVE was largely unchanged in the presence of ALP, independent of the dose (250 mg or 300 mg). There were no clinically relevant drug-drug interactions observed between ALP and EVE. CONCLUSION: The overall safety profile of ALP with EVE and EXE is manageable and reversible; no unexpected safety signals were noted compared with the individual safety profiles. Pharmacokinetics of ALP, EVE and EXE was largely unchanged in combination with each other.

Lack of everolimus diffusion in pleural fluid during pleural progression of breast cancer: A case report.

BACKGROUND: We report here a case where no everolimus pleural diffusion was evidenced at the same time of pleural progression of a metastatic breast cancer treated with everolimus and exemestane. CASE DESCRIPTION: A 69-year-old woman was diagnosed in October 2006 with stage III invasive ductal breast adenocarcinoma. After nine months of everolimus and exemestane treatment, she presented with a pleural progression. Everolimus concentration was measured in blood and in pleural fluid. Residual blood concentration was at 9.1 ng/mL, while no everolimus was observed in the pleural fluid. MANAGEMENT AND OUTCOME: Due to inefficacy of everolimus in this patient, she was switched to palbociclib and fulvestrant. CONCLUSION: Everolimus seems to have a poor diffusion in the pleural fluid.

A POETIC Phase II study of continuous oral everolimus in recurrent, radiographically progressive pediatric low-grade glioma.

BACKGROUND: To evaluate efficacy, pharmacokinetics (PK) and pharmacodynamics of single-agent everolimus in pediatric patients with radiographically progressive low-grade glioma (LGG). METHODS: Everolimus was administered at 5 mg/m2 once daily as a tablet or liquid for a planned 48-week duration or until unacceptable toxicity or disease progression. Patients with neurofibromatosis type 1 were excluded. PK and pharmacodynamic endpoints were assessed in consenting patients. RESULTS: Twenty-three eligible patients (median age 9.2 years) were enrolled. All patients received prior chemotherapy (median number of prior regimens two) and/or radiotherapy (two patients). By week 48, two patients had a partial response, 10 stable disease, and 11 clinical or radiographic progression; two discontinued study prior to 1 year (toxicity: 1, physician determination: 1). With a median follow up of 1.8 years (range 0.2-6.7 years), the 2-, 3-, and 5-year progression-free survivals (PFS) were 39 ± 11%, 26 ± 11%, and 26 ± 11%, respectively; two patients died of disease. The 2-, 3-, and 5-year overall survival (OS) were all 93 ± 6%. Grade 1 and 2 toxicities predominated; two definitively related grade 3 toxicities (mucositis and neutropenia) occurred. Grade 4 elevation of liver enzymes was possibly related in one patient. Predose blood levels showed substantial variability between patients with 45.5% below and 18.2% above the target range of 5-15 ng/mL. Pharmacodynamic analysis demonstrated significant inhibition in phospho-S6, 4E-BP1, and modulation of c-Myc expression. CONCLUSION: Daily oral everolimus provides a well-tolerated, alternative treatment for multiple recurrent, radiographically progressive pediatric LGG. Based on these results, everolimus is being investigated further for this patient population.

Model-based assessment of pharmacokinetic changes of sunitinib, tacrolimus, and everolimus in a patient with metastatic renal cell carcinoma after renal transplantation.

The safety of the coadministration of sunitinib with tacrolimus and everolimus with regard to therapeutic drug monitoring has not been demonstrated. Here, we report a patient who showed high sunitinib concentrations, in addition to pharmacokinetic changes in tacrolimus and everolimus after sunitinib therapy. A living-donor renal transplant patient treated with tacrolimus and everolimus was diagnosed with pulmonary and pleural metastases of renal cell carcinoma. The patient received sunitinib therapy (37.5 mg/day, 2 weeks on and 1 week off). This patient exhibited a high total sunitinib concentration (sunitinib, 105.8 ng/mL; N-desethyl sunitinib, 27.9 ng/mL) on day 10 postinitiation and experienced grade 3 diarrhea. The observed sunitinib concentrations were a little higher than those reported in the 421C>A polymorphism of the ATP-binding cassette subfamily G member 2 gene carrier. The observed concentrations of both tacrolimus and everolimus gradually decreased compared with the Bayesian-predicted values after the onset of sunitinib therapy, and the doses of tacrolimus and everolimus were increased. Careful therapeutic drug monitoring of sunitinib, tacrolimus, and everolimus concentrations is necessary during combination therapy, especially after episodes of diarrhea.

Flucloxacillin decreases tacrolimus blood trough levels: a single-center retrospective cohort study.

PURPOSE: Tacrolimus and everolimus are widely used to prevent allograft rejection. Both are metabolized by the hepatic cytochrome P450 (CYP) enzyme CYP3A4 and are substrate for P-glycoprotein (P-gp). Drugs influencing the activity or expression of CYP enzymes and P-gp can cause clinically relevant changes in the metabolism of immunosuppressants. Several case reports have reported that flucloxacillin appeared to decrease levels of drugs metabolized by CYP3A4 and P-gp. The magnitude of this decrease has not been reported yet. METHODS: In this single-center retrospective cohort study, we compared the tacrolimus and everolimus blood trough levels (corrected for the dose) before, during, and after flucloxacillin treatment in eleven transplant patients (tacrolimus n = 11 patients, everolimus n = 1 patient, flucloxacillin n = 11 patients). RESULTS: The median tacrolimus blood trough level decreased by 37.5% (interquartile range, IQR 26.4-49.7%) during flucloxacillin treatment. After discontinuation of flucloxacillin, the tacrolimus blood trough levels increased by a median of 33.7% (IQR 22.5-51.4%). A Wilcoxon signed-rank test showed statistically significantly lower tacrolimus trough levels during treatment with flucloxacillin compared with before (p = 0.009) and after flucloxacillin treatment (p = 0.010). In the only available case with concomitant everolimus and flucloxacillin treatment, the same pattern was observed. CONCLUSIONS: Flucloxacillin decreases tacrolimus trough levels, possibly through a CYP3A4 and/or P-gp-inducing effect. It is strongly recommended to closely monitor tacrolimus and everolimus trough levels during flucloxacillin treatment and up to 2 weeks after discontinuation of flucloxacillin.

Everolimus improves the efficacy of dasatinib in PDGFRα-driven glioma.

Pediatric and adult high-grade gliomas (HGGs) frequently harbor PDGFRA alterations. We hypothesized that cotreatment with everolimus may improve the efficacy of dasatinib in PDGFRα-driven glioma through combinatorial synergism and increased tumor accumulation of dasatinib. We performed dose-response, synergism, P-glycoprotein inhibition, and pharmacokinetic studies in in vitro and in vivo human and mouse models of HGG. Six patients with recurrent PDGFRα-driven glioma were treated with dasatinib and everolimus. We found that dasatinib effectively inhibited the proliferation of mouse and human primary HGG cells with a variety of PDGFRA alterations. Dasatinib exhibited synergy with everolimus in the treatment of HGG cells at low nanomolar concentrations of both agents, with a reduction in mTOR signaling that persisted after dasatinib treatment alone. Prolonged exposure to everolimus significantly improved the CNS retention of dasatinib and extended the survival of PPK tumor-bearing mice (mutant TP53, mutant PDGFRA, H3K27M). Six pediatric patients with glioma tolerated this combination without significant adverse events, and 4 patients with recurrent disease (n = 4) had a median overall survival of 8.5 months. Our results show that the efficacy of dasatinib treatment of PDGFRα-driven HGG was enhanced with everolimus and suggest a promising route for improving targeted therapy for this patient population.

Dose-Dependent Acute Effects of Everolimus Administration on Immunological, Neuroendocrine and Psychological Parameters in Healthy Men.

The rapamycin analogue everolimus (EVR) is a potent inhibitor of the mammalian target of rapamycin (mTOR) and clinically used to prevent allograft rejections as well as tumor growth. The pharmacokinetic and immunosuppressive efficacy of EVR have been extensively reported in patient populations and in vitro studies. However, dose-dependent ex vivo effects upon acute EVR administration in healthy volunteers are rare. Moreover, immunosuppressive drugs are associated with neuroendocrine changes and psychological disturbances. It is largely unknown so far whether and to what extend EVR affects neuroendocrine functions, mood, and anxiety in healthy individuals. Thus, in the present study, we analyzed the effects of three different clinically applied EVR doses (1.5, 2.25, and 3 mg) orally administered 4 times in a 12-hour cycle to healthy male volunteers on immunological, neuroendocrine, and psychological parameters. We observed that oral intake of medium (2.25 mg) and high doses (3 mg) of EVR efficiently suppressed T cell proliferation as well as IL-10 cytokine production in ex vivo mitogen-stimulated peripheral blood mononuclear cell. Further, acute low (1.5 mg) and medium (2.25 mg) EVR administration increased state anxiety levels accompanied by significantly elevated noradrenaline (NA) concentrations. In contrast, high-dose EVR significantly reduced plasma and saliva cortisol as well as NA levels and perceived state anxiety. Hence, these data confirm the acute immunosuppressive effects of the mTOR inhibitor EVR and provide evidence for EVR-induced alterations in neuroendocrine parameters and behavior under physiological conditions in healthy volunteers.

Absence of interaction between rivaroxaban, tacrolimus and everolimus in renal transplant recipients with deep vein thrombosis or atrial fibrillation.

No data are available on rivaroxaban use in renal transplant recipients and on its surmised interaction with immunosuppressants. The aim was to investigate potential interactions between rivaroxaban and immunosuppressants in this setting. Renal transplant recipients with a stable renal function treated with rivaroxaban and tacrolimus with or without everolimus were investigated. All drugs and creatinine concentrations were determined daily for 2 weeks after the start of anticoagulation. Blood samples were drawn at 8.00 am and 3-4 h later for trough and peak concentrations, respectively. Bleeding and thrombotic events were recorded during a minimum follow-up of 6 months. In 8 renal transplant patients, rivaroxaban levels showed a predictable pharmacokinetic trend, both at Ctrough (30-61 µg/L) and at Cpeak (143-449 µg/L), with limited variability in the 25th-75th percentile range. Tacrolimus (Ctrough 3-13 µg/L; Cpeak 3-16 µg/L), everolimus (Ctrough 3-11 µg/L; Cpeak 5-17 µg/L) and creatinine concentrations were stable as well. Immunosuppressors variability before and after rivaroxaban were 30% and 30% for tacrolimus, 27% and 29% for everolimus, respectively, as well as 14% and 3% for creatinine. For rivaroxaban monitoring, the reference change value better performed in identifying significant variations of its concentration. No patient had bleeding or thrombotic events, worsening of renal graft function, and signs of immunosuppressants toxicity during a mean follow-up of 23 (9-28) months. In conclusion, rivaroxaban does not seem to interact with tacrolimus and everolimus in renal transplant recipients. Both anticoagulant and immunosuppressive effects seem warranted, without major bleeding complications and effect on the graft function.

Severe COVID-19 in a renal transplant recipient: A focus on pharmacokinetics.

The current coronavirus disease 2019 (COVID-19) pandemic requires extra attention for immunocompromised patients, including solid organ transplant recipients. We report on a case of a 35-year-old renal transplant recipient who suffered from a severe COVID-19 pneumonia. The clinical course was complicated by extreme overexposure to the mammalian target of rapamycin inhibitor everolimus, following coadministration of chloroquine and lopinavir/ritonavir therapy. The case is illustrative for dilemmas that transplant professionals may face in the absence of evidence-based COVID-19 therapy and concurrent pressure for exploration of experimental pharmacological treatment options. However, the risk-benefit balance of experimental or off-label therapy may be weighed differently in organ transplant recipients than in otherwise healthy COVID-19 patients, owing to their immunocompromised status and potential drug interactions with immunosuppressive therapy. With this case report, we aimed to achieve increased awareness and improved management of drug-drug interactions associated with the various treatment options for COVID-19 in renal transplant patients.

Model-Informed Drug Development for Everolimus Dosing Selection in Pediatric Infant Patients.

Everolimus is currently approved in Europe as an adjunctive therapy for patients aged ≥ 2 years with tuberous sclerosis complex (TSC)-associated treatment-refractory partial-onset seizures, based on the EXIST-3 study (NCT01713946) results. As TSC-associated seizures can also affect children aged between 6 months and 2 years, a modeling and simulation (M&S) approach was undertaken to extrapolate exposure (trough plasma concentration (Cmin )) after a dose of 6 mg/m2 and reduction in seizure frequency (RSF). A physiologically based pharmacokinetic model using Simcyp was developed to predict Cmin in adult and pediatric patients, which was then used by a population pharmacodynamic model and a linear mixed effect model to predict short-term and long-term efficacy in adults (for validation) and in children, respectively. Based on the results of the M&S study, everolimus at the dose of 6 mg/m2 is anticipated to be an efficacious treatment in children 6 months to 2 years of age (up to 77.8% RSF) with concentrations within the recommended target range.

Effect of genetic polymorphisms in CYP3A4, CYP3A5, and m-TOR on everolimus blood exposure and clinical outcomes in cancer patients.

Genetic variations in CYP3A4, CYP3A5, and m-TOR could contribute to interpatient variability regarding m-TOR inhibitors pharmacokinetics or cellular effects. The purpose of this study was to evaluate the influence of selected candidate variations in these genes on everolimus pharmacokinetics, efficacy, and toxicity in cancer patients. Thirty-four patients receiving everolimus for breast (n = 22) or renal (n = 10) cancers, or neuroendocrine tumors of pancreatic origin (n = 2) were included in the study. Six variants in genes related to everolimus pharmacokinetics (CYP3A4*22 and CYP3A5*3) or pharmacodynamics (m-TOR rs2295079, rs2295080, rs2024627 and rs1057079) were genotyped. Associations with trough concentrations (C0), dose reductions, or treatment interruptions due to toxicity and progression-free survival were investigated using generalized estimating equations and Cox models. CYP3A5 nonexpressers had significantly higher C0 as compared with expressers (ßGG vs AG = + 6.32 ± 2.22 ng/mL, p = 0.004). m-TOR rs2024627 was significantly associated with an increased risk of cancer progression studied alone or as part of an haplotype (T vs C: HR = 2.60, 95% CI [1.16-5.80], p = 0.020; CTCG vs other haplotypes HR = 2.29, 95% CI [1.06-4.95], p = 0.035, respectively). This study showed that CYP3A5 expression impacts everolimus pharmacokinetics in cancer patients and identified a genetic variation in m-TOR associated with the risk of cancer progression.

Marcromolecular Architecture and Encapsulation of the Anticancer Drug Everolimus Control the Self-Assembly of Amphiphilic Polypeptide-Containing Hybrids.

Macromolecular architecture plays an important role in the self-assembly process of block copolymer amphiphiles. Herein, two series of stimuli-responsive amphiphilic 3-miktoarm star hybrid terpolypeptides and their corresponding linear analogues were synthesized exhibiting the same overall composition and molecular weight but different macromolecular architecture. The macromolecular architecture was found to be a key parameter in defining the morphology of the nanostructures formed in aqueous solutions as well as to alter the self-assembly behavior of the polymers independently of their composition. In addition, it was found that the assemblies prepared from the star-shaped polymers showed superior tolerance against enzymatic degradation due to the increased corona block density on the outer surface of the nanoparticles. Encapsulation of the hydrophobic anticancer drug Everolimus resulted in the formation of intriguing non-spherical and non-symmetric pH-responsive nanostructures, such as "stomatocytes" and "multi-compartmentalized suprapolymersomes", while the pH-triggered release of the drug was also investigated. Owing to the similarities of the developed "stomatocytes" with red blood cells, in combination with their pH-responsiveness and superior stability over enzymatic degradation, they are expected to present advanced drug delivery properties and have the ability to bypass several extra- and intracellular barriers to reach and effectively treat cancer cells.

Preparation and study of two kinds of ophthalmic nano-preparations of everolimus.

Objective: To prepare everolimus nanoformulations and increase their solubility to suit their application in the eye. Methods: The everolimus micelles was prepared by thin film dispersion method using Tween-80 (P80) and polyoxyethylene stearate (P40S) as carriers. In addition, the everolimus nanosuspension was prepared by injection method using poloxamer 407 (P407), hydroxypropyl methylcellulose (HPMC) and polyvinyl alcohol (PVA) as stabilizers. It was characterized in terms of particle size, PDI and encapsulation efficiency or drug loading. The in vitro release and in vitro rabbit scleral permeability characteristics were investigated, and the pharmacokinetics of anterior chamber drug in rabbit eyes were studied. Results: The average particle size of the micelles was (8.74 ± 0.21) nm, the encapsulation efficiency and drug loading were (90.12 ± 1.18)% and (2.14 ± 0.028)%, while the average particle size of the nanosuspension was (156.47 ± 1.10) nm, and the drug loading was (16.51 ± 0.21)%, respectively. Both in vitro release and rabbit scleral permeation models were consistent with the Higuchi equation. The pharmacokinetic experiments of aqueous humor showed that area under the curve of everolimus nanosuspension was about 3 times higher than that of micelles. Micelles could be achieved in the eye and maintained for a long time. Conclusion: The preparation of everolimus micelles or nanosuspension for eye are suitable for ocular administration and expected to be new dosage form for corneal transplantation immunological rejection or other ocular disease.