EXPRESS: SU5416 plus hypoxia but not selective VEGFR2 inhibition with cabozantinib plus hypoxia induces pulmonary hypertension in rats: potential role of BMPR2 signaling

Introduction: SU5416 plus chronic hypoxia causes pulmonary arterial hypertension (PAH) in rats and is assumed to occur through VEGFR2 inhibition. Cabozantinib is a far more potent VEGFR2 inhibitor than SU5416. Therefore, we hypothesized that cabozantinib plus hypoxia would induce severe PAH in rats. Methods: Cell proliferation and pharmacokinetic studies were performed. Rats were given SU5416 or cabozantinib SC or via osmotic pump and kept hypoxic for 3 weeks. Right ventricular systolic pressure (RVSP) and hypertrophy (RVH) were evaluated at day 14 and 28 following removal from hypoxia. RV fibrosis was evaluated with Picro-Sirius Red staining. Kinome inhibition profiles of SU5416 and cabozantinib were performed. Inhibitor binding constants of SU5416 and cabozantinib for BMPR2 were determined and Nanostring analyses of lung mRNA were performed. Results: Cabozantinib was a more potent VEGFR inhibitor than SU5416 and had a longer half-life in rats. Cabozantinib SC plus hypoxia did not induce severe PAH. RVSP at 14 and 28d post-hypoxia was 36.8 ± 2.3 mmHg and 36.2 ± 3.4 mmHg, respectively, versus 27.5 ± 1.5 mmHg in normal controls. For cabozantinib given by osmotic pump during hypoxia, RVSP was 40.0 ± 3.1 mmHg at 14d and 27.9 ± 1.9 mmHg at 28d post-hypoxia. SU5416 plus hypoxia induced severe PAH (RVSP 61.9 ± 6.1 mmHg and 64.9 ± 8.4 mmHg at 14d and 28d post-hypoxia, respectively). Cabozantinib induced less RVH (RV/(LV+IVS) at 14d post-hypoxia compared to SU5416. RV fibrosis was more extensive in the SU5416 groups compared to the Cabozantinib groups. SU5416 (but not cabozantinib) inhibited BMPR2. Nanostring analyses showed effects on pulmonary gene expression of BMP10 and VEGFR1 in the SU5416 28 day post hypoxia group. Conclusion: Selective VEGFR2 inhibition using cabozantinib plus hypoxia did not induce severe PAH. Severe PAH due to SU5416 plus hypoxia may be due to combined VEGFR2 and BMPR2 inhibition.

Strategies for intra-amniotic administration of fetal therapy in a rabbit model of intrauterine growth restriction

Intrauterine growth restriction affects up to 10% of all pregnancies, leading to fetal programming with detrimental consequences for lifelong health. However, no therapeutic strategies have so far been effective to ameliorate these consequences. Our previous study has demonstrated that a single dose of nutrients administered into the amniotic cavity, bypassing the often dysfunctional placenta via intra-amniotic administration, improved survival at birth but not birthweight in an intrauterine growth restriction rabbit model. The aim of this study was to further develop an effective strategy for intra-amniotic fetal therapy in an animal model. Intrauterine growth restriction was induced by selective ligation of uteroplacental vessels on one uterine horn of pregnant rabbits at gestational day 25, and fetuses were delivered by cesarean section on GD30. During the five days of intrauterine growth restriction development, three different methods of intra-amniotic administration were used: continuous intra-amniotic infusion by osmotic pump, multiple intra-amniotic injections, and single fetal intraperitoneal injection. Technical feasibility, capability to systematically reach the fetus, and survival and birthweight of the derived offspring were evaluated for each technique. Continuous intra-amniotic infusion by osmotic pump was not feasible owing to the high occurrence of catheter displacement and amnion rupture, while methods using two intra-amniotic injections and one fetal intraperitoneal injection were technically feasible but compromised fetal survival. Taking into account all the numerous factors affecting intra-amniotic fetal therapy in the intrauterine growth restriction rabbit model, we conclude that an optimal therapeutic strategy with low technical failure and positive fetal impact on both survival and birthweight still needs to be found.

Chloroquine, an Anti-Malaria Drug as Effective Prevention for Hantavirus Infections

We investigated whether chloroquine can prevent hantavirus infection and disease in vitro and in vivo, using the Hantaan virus newborn C57BL/6 mice model and the Syrian hamster model for Andes virus. In vitro antiviral experiments were performed using Vero E6 cells, and Old World and New World hantavirus species. Hantavirus RNA was detected using quantitative RT-PCR. For all hantavirus species tested, results indicate that the IC50 of chloroquine (mean 10.2 ± 1.43 μM) is significantly lower than the CC50 (mean 260 ± 2.52 μM) yielding an overall selectivity index of 25.5. We also investigated the potential of chloroquine to prevent death in newborn mice after Hantaan virus infection and its antiviral effect in the hantavirus Syrian hamster model. For this purpose, C57Bl/6 mother mice were treated subcutaneously with daily doses of chloroquine. Subsequently, 1-day-old suckling mice were inoculated intracerebrally with 5 x 102 Hantaan virus particles. In litters of untreated mothers, none of the pups survived challenge. The highest survival rate (72.7% of pups) was found when mother mice were administered a concentration of 10 mg/kg chloroquine. Survival rates declined in a dose-dependent manner, with 47.6% survival when treated with 5 mg/kg chloroquine, and 4.2% when treated with 1 mg/kg chloroquine. Assessing the antiviral therapeutic and prophylactic effect of chloroquine in the Syrian hamster model was done using two different administration routes (intraperitoneally and subcutaneously using an osmotic pump system). Evaluating the prophylactic effect, a delay in onset of disease was noted and for the osmotic pump, 60% survival was observed. Our results show that chloroquine can be highly effective against Hantaan virus infection in newborn mice and against Andes virus in Syrian hamsters.

A Review of Novel Drug Delivery Controlled Porosity Osmotic Pump Tablets Therapeutic Approach and Future Trend

The review work is comprised the enhancement of bioavailability and increase therapeutic efficacy. The porous osmotic pump tablets were designed using D‐Optimal design and numerical optimization technique was applied to find out the best formulation. Another hand an osmotic pump (OP) were designed and evaluated with the aim to deliver drug in a controlled manner. Osmotic agent and pore former was considered as independent variables. Drug release rate at 2 h, 4 h, 8 h, 12 h, T50% and release exponent (n) were taken as responses. The increase in concentration of pore former and osmotic agent after a limit, changes the release was measured. The optimized formulation follows mechanism measured. The FT‐IR and DSC studies revealed that no physicochemical interaction between excipients and drug. The influence of pH and agitation intensity on the release of drug was studied and the release mechanism was through osmosis. Stability studies revealed that optimized formulation was stable. The result of D‐ Optimal design and ANOVA studies reveals that osmotic agent and pore former have significant effect on the drug release up to 12 h. The observed independent variables were found to be very close to predicted values of most satisfactory formulation which demonstrates the feasibility. Keywords: osmotic pump, pore former, bioavailability