Pharmacokinetics and tissue distribution of spray-dried carboplatin microspheres: lung targeting via intravenous route

Spray-Dried Microspheres of Carboplatin: Technology to Develop Longer-Acting Injectable with Improved Physio-Chemical Stability, Toxicity, and Therapeutics

The present study aims to develop carboplatin injectable microspheres using spray-drying technology. The optimized powdered microspheres (MS-19-ST2) were morphologically spherical, with a 1.795 μm particle size and good micromeritic properties. Under normal temperature conditions, the MS-19-ST2 formulation exhibited a sustained release behaviour following first-order drug release kinetics with no compatibility issues with aluminium syringes. Furthermore, MS-19-ST2 formulation outperformed its commercial counterpart in terms of in vivo pharmaco-kinetics and -dynamics (MRT-13.9 ± 0.9 h, T_1/2-8.2 ± 0.3 h, tumour inhibition-74.5%). Additionally, the MS-19-ST2 formulation was much safer to use than its commercial counterpart, as observed from the results of ex vivo (haemolytic, MTT, and cell apoptosis assays) and in vivo (14-day acute and 28-day sub-acute) toxicity studies. The above results confirm the MS-19-ST2 formulation as a good candidate to commercialize carboplatin in a powdered microsphere form (stable for 24 h after reconstitution) with improved pharmacokinetics, therapeutic, and toxicity profile.

Lung Targeted Lipopolymeric Microspheres of Dexamethasone for the Treatment of ARDS

Acute respiratory distress syndrome (ARDS), a catastrophic illness of multifactorial etiology, involves a rapid upsurge in inflammatory cytokines that leads to hypoxemic respiratory failure. Dexamethasone, a synthetic corticosteroid, mitigates the glucocorticoid-receptor-mediated inflammation and accelerates tissue homeostasis towards disease resolution. To minimize non-target organ side effects arising from frequent and chronic use of dexamethasone, we designed biodegradable, lung-targeted microspheres with sustained release profiles. Dexamethasone-loaded lipopolymeric microspheres of PLGA (Poly Lactic-co-Glycolic Acid) and DPPC (Dipalmitoylphosphatidylcholine) stabilized with vitamin E TPGS (D-α-tocopheryl polyethylene glycol succinate) were prepared by a single emulsion technique that had a mean diameter of 8.83 ± 0.32 μm and were spherical in shape as revealed from electron microscopy imaging. Pharmacokinetic and biodistribution patterns studied in the lungs, liver, and spleen of Wistar rats showed high selectivity and targeting efficiency for the lung tissue (re 13.98). As a proof-of-concept, in vivo efficacy of the microspheres was tested in the lipopolysaccharide-induced ARDS model in rats. Inflammation markers such as IL-1β, IL-6, and TNF-α, quantified in the bronchoalveolar lavage fluid indicated major improvement in rats treated with dexamethasone microspheres by intravenous route. Additionally, the microspheres substantially inhibited the protein infiltration, neutrophil accumulation and lipid peroxidation in the lungs of ARDS bearing rats, suggesting a reduction in oxidative stress. Histopathology showed decreased damage to the pulmonary tissue upon treatment with the dexamethasone-loaded microspheres. The multipronged formulation technology approach can thus serve as a potential treatment modality for reducing lung inflammation in ARDS. An improved therapeutic profile would help to reduce the dose, dosing frequency and, eventually, the toxicity.

Evaluation of Mogroside V as a Promising Carrier in Drug Delivery: Improving the Bioavailability and Liver Distribution of Silybin

The objective of this work was to investigate the capacity of mogroside V (MOG-V), a food additive, as a novel carrier to improve the bioavailability and liver distribution of silybin (SLY). Solid dispersion particles (SDPs) of SLY/MOG-V were prepared utilizing the solvent evaporation method. The physicochemical characterizations of SDPs were evaluated by using dynamic light scattering (DLS), differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD) measurements. DLS results demonstrated the formation of nanoparticles (206 nm) of SDPs in water. DSC and PXRD analysis revealed that SLY was in amorphous form or molecularly dispersed in SDPs. SDPs also exhibited a major increase in both dissolution rate and saturation solubility, as evidenced by a 1931-fold improvement (2201 μg/mL) in solubility compared with pure SLY (1.14 μg/mL). The pharmacokinetic study in rats showed that oral absorption of SLY/MOG-V SDPs was dramatically increased. The mean value of AUC until 12 h for SLY/MOG-V SDPs (27,481 ng·min/mL) was 24.5-fold higher than that of pure SLY (1122 ng·min/mL). In vivo tissue distribution experiment in mice confirmed that the major distribution tissue was changed from lungs to liver after SLY was loaded into MOG-V. In addition, even orally administrated to mice at a high dose (4.2 g/kg), MOG-V exhibited no undesirable effect on the plasma glucose concentrations. Thus, MOG-V may have the applicability to serve as an ideal excipient for solubilization or as a novel liver targeting carrier for the delivery of SLY.

An Efficient, Lung-Targeted, Drug-Delivery System To Treat Asthma Via Microparticles

BACKGROUND

Chronic diseases such as diabetes, asthma, and heart disease are the leading causes of death in developing countries. Public health plays an important role in preventing such diseases to improve individuals' quality of life. Conventional dosage schemes used in public health to cure various diseases generally lead to undesirable side effects and renders the overall treatment ineffective. For example, a required concentration of drug cannot reach the lungs using conventional methods to cure asthma. Microspheres have emerged as a confirmed drug-delivery system to cure asthma.

METHOD

In this paper, a salbutamol-loaded poly lactic acid-co-glycolic acid-polyethylene glycol (PLGA-PEG) microsphere (SPP)-based formulation was prepared using a Buchi B-90 nanospray drier. Face-centered central composite design (CCD) was applied to optimize the spray-drying process.

RESULTS

The drug content and product yield were found to be 72%±0.8% and 86%±0.4%, respectively; drug release (91.1%) peaked for up to 12 hrs in vitro. Microspheres obtained from the spray dryer were found to be shriveled. The experiments were carried out and verified using various groups of rabbits. In our study, the particle size (8.24 µm) was observed to be an essential parameter for drug delivery. The in vivo results indicated that the targeting efficacy and drug concentration in the lung was higher with the salbutamol-loaded PLGA-PEG SPP formulation (1,410.1±10.11 µg/g, 15 mins), as compared to the conventional formulation (92±0.56 µg/g, 10 min). The final product was stable under 5°C±2°C, 25°C±2°C, and 40°C±2°C/75%±5% relative humidity. In addition, these co-polymers have a good safety profile, as determined by testing on human alveolar basal epithelium A549 cell lines.

CONCLUSION

Our results prove that microspheres are an alternative drug-delivery system for lung-targeted asthma treatments used in public health.

Lung-targeting drug delivery system of baicalin-loaded nanoliposomes: development, biodistribution in rabbits, and pharmacodynamics in nude mice bearing orthotopic human lung cancer

The present study aims to develop a kind of novel nanoliposomes for the lung-targeting delivery system of baicalin as a Chinese medicine monomer. Baicalin-loaded nanoliposomes were prepared by the effervescent dispersion and lyophilized techniques. Baicalin-loaded nanoliposomes had an average particle size of 131.7±11.7 nm with 0.19±0.02 polydispersity index, 82.8%±1.24% entrapment efficiency and 90.47%±0.93% of yield and sustaining drug release effect over 24 h and were stable for 12 months at least. In vitro no hemolytic activity was observed for the experimental drug concentration. After intravenous administration of baicalin-loaded nanoliposomes to rabbits, drug concentration in the lungs was the highest among the tested organs at all time points and was significantly higher than that of its solution. For the targeting parameters, the relative intake rate and the ratio of peak concentration of lung were 4.837 and 2.789, respectively. Compared with plasma, liver, spleen, and kidney, the ratios of targeting efficacy (T_e)_liposomes to (T_e)_injection of lung were increased by a factor of 14.131, 1.893, 3.357, and 3.470, respectively. Furthermore, the results showed that the baicalin-loaded nanoliposomes did not induce lung injury. Importantly, baicalin-loaded nanoliposomes showed better antitumor therapeutic efficacy in the nude mice bearing orthotopic human lung cancer with the median survival time of blank liposomes (11.40±0.16 days), baicalin solution (17.30±0.47 days), and baicalin-loaded nanoliposomes (25.90±0.53 days). Therefore, the liposome is a promising drug carrier with an excellent lung-targeting property and therapeutic effect for the treatment of lung disease, such as lung cancer.

Application of a novel 3-fluid nozzle spray drying process for the microencapsulation of therapeutic agents using incompatible drug-polymer solutions

The aim of this study was to evaluate a novel 3-fluid concentric nozzle (3-N) spray drying process for the microencapsulation of omeprazole sodium (OME) using Eudragit L100 (EL100). Feed solutions containing OME and/or EL100 in ethanol were assessed visually for OME stability. Addition of OME solution to EL100 solution resulted in precipitation of OME followed by degradation of OME reflected by a colour change from colourless to purple and brown. This was related to the low pH of 2.8 of the EL100 solution at which OME is unstable. Precipitation and progressive discoloration of the 2-fluid nozzle (2-N) feed solution was observed over the spray drying time course. In contrast, 3-N solutions of EL100 or OME in ethanol were stable over the spray drying period. Microparticles prepared using either nozzle showed similar characteristics and outer morphology however the internal morphology was different. DSC showed a homogenous matrix of drug and polymer for 2-N microparticles while 3-N microparticles had defined drug and polymer regions distributed as core and coat. The results of this study demonstrate that the novel 3-N spray drying process can allow the microencapsulation of a drug using an incompatible polymer and maintain the drug and polymer in separate regions of the microparticles.