In Vitro and In Vivo Validation of GATA-3 Suppression for Induction of Adipogenesis and Improving Insulin Sensitivity.

Impaired adipogenesis is associated with the development of insulin resistance and an increased risk of type 2 diabetes (T2D). GATA Binding Protein 3 (GATA3) is implicated in impaired adipogenesis and the onset of insulin resistance. Therefore, we hypothesize that inhibition of GATA3 could promote adipogenesis, restore healthy fat distribution, and enhance insulin signaling. Primary human preadipocytes were treated with GATA3 inhibitor (DNAzyme hgd40). Cell proliferation, adipogenic capacity, gene expression, and insulin signaling were measured following well-established protocols. BALB/c mice were treated with DNAzyme hgd40 over a period of 2 weeks. Liposomes loaded with DNAzyme hgd40, pioglitazone (positive), or vehicle (negative) controls were administered subcutaneously every 2 days at the right thigh. At the end of the study, adipose tissues were collected and weighed from the site of injection, the opposite side, and the omental depot. Antioxidant enzyme (superoxide dismutase and catalase) activities were assessed in animals' sera, and gene expression was measured using well-established protocols. In vitro GATA3 inhibition induced the adipogenesis of primary human preadipocytes and enhanced insulin signaling through the reduced expression of p70S6K. In vivo GATA3 inhibition promoted adipogenesis at the site of injection and reduced MCP-1 expression. GATA3 inhibition also reduced omental tissue size and PPARγ expression. These findings suggest that modulating GATA3 expression offers a potential therapeutic benefit by correcting impaired adipogenesis, promoting healthy fat distribution, improving insulin sensitivity, and potentially lowering the risk of T2D.

Impact of nanosizing on the formation and characteristics of polymethacrylate films: micro- versus nano-suspensions.

Aqueous-based film coating suspensions are associated with reliance on alkalinising reagents and poor film formation. The impact of particle size in this process and resultant film properties remains unclear. This study offers the first direct comparison of film formation properties between aqueous micro- and nano-suspensions of the enteric polymer Eudragit S100. High-pressure homogenisation was employed to produce nano-suspensions of the enteric polymer. Formed enteric suspensions (micro- and nano-) were evaluated in terms of size, morphology, and ability to form film; with resultant films analysed in terms of; film thickness, mechanical and thermoplastic properties, water uptake, weight loss, and drug permeability in acidic medium. High-pressure homogenisation yielded particles within a submicron range (150-200 nm). Produced nano-suspensions formed significantly thinner films (p < 0.01), at lower plasticiser concentrations, than films cast from micro-suspensions (differences in thickness up to 100 µm); however, exhibited comparative gastro-resistant properties (p > 0.05) in terms of water uptake (∼25% w/w), weight loss (<16% w/w) and drug permeability (<0.1%). Interestingly, nano-suspension-based films exhibited lower glass transition temperatures (Tg) (p < 0.01), when compared to films cast from micro-suspensions (∼7-20 °C difference), indicating enhanced plasticisation. This was reflected in film mechanical properties; where nano-suspension-based films demonstrated significantly lower tensile strength (p < 0.01) and higher percentage elongation (p < 0.05), suggesting high elasticity. Thinner, highly elastic films were formed from nano-suspensions, compared to films cast from micro-suspensions, exhibiting comparative properties; obviating the need for alkalinising agents and high concentrations of plasticiser.

Galactosylated iron oxide nanoparticles for enhancing oral bioavailability of ceftriaxone.

The current study focuses on the development, characterization, biocompatibility investigation and oral bioavailability evaluation of ceftriaxone (CFT)-loaded lactobionic acid (LBA)-functionalized iron oxide magnetic nanoparticles (MNP-LBA). Atomic force microscopy and dynamic light scattering showed that the developed CFT-loaded MNP-LBA is spherical, with a measured hydrodynamic size of 147 ± 15.9 nm and negative zeta potential values (-35 ± 0.58 mV). Fourier transformed infrared analysis revealed interactions between the nanocarrier and the drug. Nanoparticles showed high drug entrapment efficiencies of 91.5 ± 2.2%, and the drug was released gradually in vitro and shows prolonged in vitro stability using simulated gastrointestinal (GI) fluids. The formulations were found to be highly biocompatible (up to 100 µg/mL) and hemocompatible (up to 1.0 mg/mL). Using an albino rabbit model, the formulation showed a significant enhancement in drug plasma concentration up to 14.46 ± 2.5 µg/mL in comparison with its control (1.96 ± 0.58 µg/mL). Overall, the developed MNP-LBA formulation was found promising for provision of high-drug entrapment, gradual drug release and was appropriate for enhancing the oral delivery of CFT.

Piroxicam loaded polymer hybrid microspheres based tablets with modified release kinetics: Development, characterization and in vivo evaluation.

Piroxicam (PC) is a non-steroidal anti-inflammatory drug characterized by poor aqueous solubility and reported to cause and impart crucial GIT irritation, bleeding, peptic and duodenal ulcer. Engineering of PC loaded microcapsules and its surface modification using different polymers has become the popular approach to address the said issues. The purpose of the study was to develop new PC loaded gastro-protective polymer hybrid microspheres (PHM) with subsequent conversion to tablet dosage form having modified dissolution rate and improved bioavailability. The crystallinity of the PC loaded PHM were established through powder X-ray diffraction. The optimised microspheres, PC-M1 with particle size 32±3.0µm, entrapment efficiency 83.78±2.5% and in vitro drug release 87.1±2.6% were further subjected to tablets development and in vivo evaluation. The in vitro drug release study conducted for PHM at pH media 1.2 and 6.8 demonstrated retarded and enhanced drug release rates (P<0.001) respectively. Both accelerated and real time stability studies confirmed stability of the PC loaded PHM based tablets. A substantial improvement in the drug plasma concentration 12.6±2.36 (P<0.001) was observed for the produced tablets compared to the marketed formulations.

A Facile and Novel Approach to Manufacture Paclitaxel-Loaded Proliposome Tablet Formulations of Micro or Nano Vesicles for Nebulization.

PURPOSE: The aim of this study was to develop novel paclitaxel-loaded proliposome tablet formulations for pulmonary drug delivery. METHOD: Proliposome powder formulations (i.e. F1 - F27) were prepared employing Lactose monohydrate (LMH), Microcrystalline cellulose (MCC) or Starch as a carbohydrate carriers and Soya phosphatidylcholine (SPC), Hydrogenated soya phosphatidylcholine (HSPC) or Dimyristoly phosphatidylcholine (DMPC) as a phospholipid. Proliposome powder formulations were prepared in 1:5, 1:15 or 1:25 w/w lipid phase to carrier ratio (lipid phase; comprising of phospholipid and cholesterol in 1:1 M ratio) and Paclitaxel (PTX) was used as model anticancer drug. RESULTS: Based on flowability studies, out of 27 formulations; F3, F6, and F9 formulations were selected as they exhibited an excellent angle of repose (AOR) (17.24 ± 0.43, 16.41 ± 0.52 and 15.16 ± 0.72°), comparatively lower size of vesicles (i.e. 5.35 ± 0.76, 6.27 ± 0.59 and 5.43 ± 0.68 µm) and good compressibility index (14.81 ± 0.36, 15.01 ± 0.35 and 14.56 ± 0.14) via Carr's index. The selected formulations were reduced into Nano (N) vesicles via probe sonication, followed by spray drying (SD) to get a dry powder of these formulations as F3SDN, F6SDN and F9SDN, and gave high yield (>53%) and exhibited poor to very poor compressibility index values via Carr's Index. Post tablet manufacturing, F3 tablets formulation showed uniform weight uniformity (129.40 ± 3.85 mg), good crushing strength (14.08 ± 1.95 N), precise tablet thickness (2.33 ± 0.51 mm) and a short disintegration time of 14.35 ± 0.56 min, passing all quality control tests in accordance with British Pharmacopeia (BP). Upon nebulization of F3 tablets formulation, Ultrasonic nebulizer showed better nebulization time (8.75 ± 0.86 min) and high output rate (421.06 ± 7.19 mg/min) when compared to Vibrating mesh nebulizer. PTX-loaded F3 tablet formulations were identified as toxic (60% cell viability) to cancer MRC-5 SV2 cell lines while safe to normal MRC-5 cell lines. CONCLUSION: Overall, in this study LMH was identified as a superior carbohydrate carrier for proliposome tablet manufacturing in a 1:25 w/w lipid to carrier ratio for in-vitro nebulization via Ultrasonic nebulizer.

Spray-dried alginate microparticles for potential intranasal delivery of ropinirole hydrochloride: development, characterization and histopathological evaluation.

Ropinirole hydrochloride (RH) is an anti-Parkinson drug with relativity low oral bioavailability owing to its extensive hepatic first pass metabolism. Spray-dried mucoadhesive alginate microspheres of RH were developed and characterized followed by histopathological evaluation using nasal tissue isolated from sheep. Spherical microparticles having high product yield (around 70%) were obtained when the inlet temperature of spray drying was 140 °C. Fourier Transform Infrared (FTIR) studies revealed the compatibility of the drug with the polymer, and scanning electron microscopy (SEM) showed that drug-loaded microparticles were spherical, and the apparent surface roughness was inversely related to the ratio of polymer to drug. Furthermore, size of the spray-dried particles were in the range of 2.5-4.37 µm, depending on formulation. All formulations had high drug encapsulation efficiencies (101-106%). Drug loaded into the polymeric particles was in the amorphous state and drug molecules were molecularly dispersed in the polymeric matrix of the microparticles which were revealed by X-ray diffraction and differential scanning calorimetry (DSC), respectively. The in vitro drug release was influenced by polymer concentration. Histopathological study demonstrated that RH-loaded sodium alginate microparticles was safe to nasal epithelium. In conclusion, spray drying of RH using sodium alginate polymer has produced microparticles of suitable characteristics for potential intranasal administration.

Development, characterization and stability evaluation of ciprofloxacin-loaded parenteral nutrition nanoemulsions.

In this study, two licensed total parenteral nanoemulsion formulations (Clinoleic® and Intralipid®) were loaded with ciprofloxacin (CP). The physicochemical characteristics and stability profiles of the formulations were investigated using a range of drug concentrations. Furthermore, formulation stability was evaluated over a period of six months at room temperature (RT) or 4 °C. Loading CP into nanoemulsions resulted in no significant differences in their measured droplet size, polydispersity index (PI), zeta potential, and pH. Drug entrapment efficiency (EE) was relatively high for all formulations, regardless of nanoemulsion type, and the drug release was sustained over 24 h. Stability studies of all formulations were performed at 4 °C and RT for 180 and 60 days, respectively. At 4 °C for 180 days, both Clinoleic® and Intralipid® formulations at a range of drug concentrations (1-10 mg/ml) showed high stabilities measured periodically by the average droplet sizes, PI, pH, and zeta potential values. Similar results, but pH values, were shown when the formulations for both nanoemulsion stored at RT for 60 days. Overall, this study has shown that CP was successfully loaded into clinically licensed TPN lipid nanoemulsions. The resultant CP-loaded nanoemulsion formulations demonstrated desirable physicochemical properties and were stable upon storage at 4 °C for up to six months.

Preparation and characterization of letrozole-loaded poly(d,l-lactide) nanoparticles for drug delivery in breast cancer therapy.

Letrozole (LTZ), an aromatase inhibitor used for the treatment of hormonally-positive breast cancer in postmenopausal women, has poor water solubility, rapid metabolism, and a range of side effects. In this study, polymer-based nanoparticles (NPs) incorporating the drug have been designed and characterized, aimed to control the release, potentially maximize the therapeutic efficiency, and minimize the side effects of the drug. LTZ was incorporated into poly(d,l-lactide) (PDLLA) NPs by employing the emulsion-solvent evaporation technique using a range of drug concentrations. Loaded drug and drug-polymer interactions were studied using X-ray diffraction and NPs morphology was evaluated using scanning electron microscopy (SEM). Particle size distribution (PSD) and zeta potential of the NPs were analyzed using dynamic light scattering (DLS) and laser Doppler velocimetry (LDV), respectively. Drug content and release profile studies were carried out and determined using ultra performance liquid chromatography (UPLC). The yield of LTZ-PDLLA NPs reached as high as 85%. The NPs were spherical and smooth, regardless of LTZ concentration in the formulation. However, particle size increased from 241.6 ± 1.2 to 348.7 ± 6.1 nm upon increasing LTZ concentration from 0 to 30% w/w, with entrapment efficiencies reaching up to 96.8%. Drug release from the polymeric matrix was best described by Higuchi model with a predominant diffusion-based mechanism. More than 15, 46, and 86% of LTZ was released in a controlled fashion over 30 d from the 10, 20, and 30% LTZ-PDLLA NPs, respectively. Overall, LTZ-PDLLA NPs were designed with appropriate size and surface charge, high drug loading, superior entrapment efficiency, and prolonged release profile.

Ethanol-based proliposome delivery systems of paclitaxel for in vitro application against brain cancer cells.

In this study the anticancer activity of paclitaxel-loaded nano-liposomes on glioma cell lines was investigated. Soya phosphatidylcholine:cholesterol (SPC:Chol), hydrogenated soya phosphatidylcholine:cholesterol (HSPC:Chol) or dipalmitoylphosphatidylcholine:cholesterol (DPPC:Chol) in 1:1 mole ratio were used to prepare ethanol-based proliposomes. Following hydration of proliposomes, the size of resulting vesicles was subsequently reduced to nanometer scale via probe-sonication. The resulting formulations were characterized in terms of size, zeta potential and morphology of the vesicles, and entrapment efficiency of paclitaxel (PX) as well as the final pH of the preparations. DPPC-liposomes entrapped 35-92% of PX compared to 27-74% and 25-60% entrapped by liposomes made from SPC and HSPC formulations respectively, depending on drug concentration. The entrapment efficiency of liposomes was dependent on the lipid bilayer properties and ability of PX to modify surface charge of the vesicles. In vitro cytotoxicity studies revealed that PX-liposome formulations were more selective at inhibiting the malignant cells. The cytotoxicity of PX-liposomes was dependent on their drug-entrapment efficiency. This study has shown PX-liposomes generated from proliposomes have selective activity against glioma cell lines, and the synthetic DPPC phospholipid was most suitable for maximized drug entrapment and highest activity against the malignant cells in vitro.

Preparation and optimization of monodisperse polymeric microparticles using modified vibrating orifice aerosol generator for controlled delivery of letrozole in breast cancer therapy.

Letrozole (LTZ) is effective for the treatment of hormone-receptor-positive breast cancer in postmenopausal women. In this work, and for the first time, using vibrating orifice aerosol generator (VOAG) technology, monodisperse poly-ε-caprolactone (PCL), and poly (D, L-Lactide) (PDLLA) LTZ-loaded microparticles were prepared and found to elicit selective high cytotoxicity against cancerous breast cells with no apparent toxicity on healthy cells in vitro. Plackett-Burman experimental design was utilized to identify the most significant factors affecting particle size distribution to optimize the prepared particles. The generated microparticles were characterized in terms of microscopic morphology, size, zeta potential, drug entrapment efficiency, and release profile over one-month period. Long-term cytotoxicity of the microparticles was also investigated using MCF-7 human breast cancer cell lines in comparison with primary mammary epithelial cells (MEC). The prepared polymeric particles were monodispersed, spherical, and apparently smooth, regardless of the polymer used or the loaded LTZ concentration. Particle size varied from 15.6 to 91.6 µm and from 22.7 to 99.6 µm with size distribution (expressed as span values) ranging from 0.22 to 1.24 and from 0.29 to 1.48 for PCL and PDLLA based microparticles, respectively. Upon optimizing the manufacture parameters, span was reduced to 0.162-0.195. Drug entrapment reached as high as 96.8%, and drug release from PDLLA and PCL followed a biphasic zero-order release using 5 or 30% w/w drug loading in the formulations. Long-term in vitro cytotoxicity studies indicated that microparticles formulations significantly inhibited the growth of MCF-7 cell line over a prolonged period of time but did not have toxic effects on the normal breast epithelial cells.

Studies of the precipitation pattern of paclitaxel in intravenous infusions and rat plasma using laser nephelometry.

Cremophor EL (CrEL) is commonly used to solubilize paclitaxel (Ptx); a widely established anticancer agent used against many types of cancer. Using laser-based microplate nephelometry, in this work we assessed the precipitation kinetics of Ptx in CrEL-containing formulations upon dilutions with different infusion media or upon introduction into rat plasma. The precipitation profile of Ptx was assessed for a Taxol-like formulation and compared with a preparation with reduced CrEL content. These two formulations were diluted at various ratios in compatible infusion media and with or without rat plasma. The percentages of Ptx precipitated in dilution media and protein-binding in plasma were quantified using HPLC. The findings of turbidity measurements were in good agreement with HPLC. Despite the presence of albumin, it was possible to assess turbidity within infusion solutions and predict Ptx precipitation. Upon addition to plasma, no precipitation in Taxol-like formulation occurred after 2 h. In contrast, precipitation occurred immediately in CrEL-reduced formulation. It is possible that the high percentage of protein-bound Ptx in plasma (98.5-99.2%) has inhibited drug precipitation. Turbidity measurements using laser nephelometry can provide a rapid screening tool when developing intravenous formulations for poorly soluble drugs, such as Ptx and assess its stability upon dilution in animal plasma.

Proliposome Powders for the Generation of Liposomes: the Influence of Carbohydrate Carrier and Separation Conditions on Crystallinity and Entrapment of a Model Antiasthma Steroid.

Formulation effects on the entrapment of beclometasone dipropionate (BDP) in liposomes generated by hydration of proliposomes were studied, using the high-density dispersion medium deuterium oxide in comparison to deionized water (DW). Proliposomes incorporating BDP (2 mol% of the lipid phase consisting of soya phosphatidylcholine (SPC) and cholesterol; 1:1) were manufactured, using lactose monohydrate (LMH), sorbitol or D-mannitol as carbohydrate carriers (1:5 w/w lipid to carrier). Following hydration of proliposomes, separation of BDP-entrapped liposomes from the unentrapped (free) BDP at an optimized centrifugation duration of 90 min and a centrifugation force of 15,500g were identified. The dispersion medium was found to have a major influence on separation of BDP-entrapped liposomes from the unentrapped drug. Entrapment efficiency values were higher than 95% as estimated when DW was used. By contrast, the entrapment efficiency was 19.69 ± 5.88, 28.78 ± 4.69 and 34.84 ± 3.62% upon using D2O as a dispersion medium (for LMH-, sorbitol- and D-mannitol-based proliposomes, respectively). The similarity in size of liposomes and BDP crystals was found to be responsible for co-sedimentation of liposomes and free BDP crystals upon centrifugation in DW, giving rise to the falsely high entrapment values estimated. This was remedied by the use of D2O as confirmed by light microscopy, nuclear magnetic resonance (1HNMR), X-ray diffraction (XRD) and entrapment studies. This study showed that carrier type has a significant influence on the entrapment of BDP in liposomes generated from proliposomes, and using D2O is essential for accurate determination of steroid entrapment in the vesicles.

Spray-Dried Proliposome Microparticles for High-Performance Aerosol Delivery Using a Monodose Powder Inhaler.

Proliposome formulations containing salbutamol sulphate (SS) were developed using spray drying, and the effects of carrier type (lactose monohydrate (LMH) or mannitol) and lipid to carrier ratio were evaluated. The lipid phase comprised soy phosphatidylcholine (SPC) and cholesterol (1:1), and the ratios of lipid to carrier were 1:2, 1:4, 1:6, 1:8 or 1:10 w/w. X-ray powder diffraction (XRPD) revealed an interaction between the components of the proliposome particles, and scanning electron microscopy (SEM) showed that mannitol-based proliposomes were uniformly sized and spherical, whilst LMH-based proliposomes were irregular and relatively large. Using a two-stage impinger (TSI), fine particle fraction (FPF) values of the proliposomes were higher for mannitol-based formulations, reaching 52.6%, which was attributed to the better flow properties when mannitol was used as carrier. Following hydration of proliposomes, transmission electron microscopy (TEM) demonstrated that vesicles generated from mannitol-based formulations were oligolamellar, whilst LMH-based proliposomes generated 'worm-like' structures and vesicle clusters. Vesicle size decreased upon increasing carrier to lipid ratio, and the zeta potential values were negative. Drug entrapment efficiency (EE) was higher for liposomes generated from LMH-based proliposomes, reaching 37.76% when 1:2 lipid to carrier ratio was used. The in vitro drug release profile was similar for both carriers when 1:6 lipid to carrier ratio was used. This study showed that spray drying can produce inhalable proliposome microparticles that can generate liposomes upon contact with an aqueous phase, and the FPF of proliposomes and the EE offered by liposomes were formulation-dependent.

Liposome Delivery Systems for Inhalation: A Critical Review Highlighting Formulation Issues and Anticancer Applications.

This is a critical review on research conducted in the field of pulmonary delivery of liposomes. Issues relating to the mechanism of nebulisation and liposome composition were appraised and correlated with literature reports of liposome formulations used in clinical trials to understand the role of liposome size and composition on therapeutic outcome. A major highlight was liposome inhalation for the treatment of lung cancers. Many in vivo studies that explored the potential of liposomes as anticancer carrier systems were evaluated, including animal studies and clinical trials. Liposomes can entrap anticancer drugs and localise their action in the lung following pulmonary delivery. The safety of inhaled liposomes incorporating anticancer drugs depends on the anticancer agent used and the amount of drug delivered to the target cancer in the lung. The difficulty of efficient targeting of liposomal anticancer aerosols to the cancerous tissues within the lung may result in low doses reaching the target site. Overall, following the success of liposomes as inhalable carriers in the treatment of lung infections, it is expected that more focus from research and development will be given to designing inhalable liposome carriers for the treatment of other lung diseases, including pulmonary cancers. The successful development of anticancer liposomes for inhalation may depend on the future development of effective aerosolisation devices and better targeted liposomes to maximise the benefit of therapy and reduce the potential for local and systemic adverse effects.

Instrumentation of Flow-Through USP IV Dissolution Apparatus to Assess Poorly Soluble Basic Drug Products: a Technical Note.

Supersaturation and precipitation are common limitations encountered especially with poorly soluble basic drugs. The aims of this work were to explore the pattern of dissolution and precipitation of poorly soluble basic drugs using a United States Pharmacopoeia (USP) IV dissolution apparatus and to compare it to the widely used USP II dissolution apparatus. In order to investigate the influence of gastric emptying time on bioavailability, tables of two model drugs (dipyridamole 100 mg and cinnarizine 15 mg) were investigated and pH change from 1.2 to 6.8 were achieved after 10, 20 or 30 min using USP II or USP IV dissolution apparatuses. Using USP II, dipyridamole and cinnarizine concentrations dropped instantly as a result of drug precipitation with drug crystals evident in the dissolution vessel. At pH change times of 10, 20 and 30 min, the total amount of dissolved drug was dependent on pH change time. Using USP IV, at a flow rate of 8 ml/min, it was possible to have comparable release to agitation at 50 rpm using USP II suggesting that comparable hydrodynamic forces are possible. No drop in drug percentage occurs as the dissolved fraction was readily emptied from the flow cell, preventing drug accumulation in the dissolution medium. However, a negligible percentage of drug release took place following pH change. In conclusion, the use of the flow-through cell dissolution provided laminar flow, use of realistic fluid volumes and avoided precipitation of dissolved drug fraction in the gastric phase as it is discharged before pH change.

A facile approach to manufacturing non-ionic surfactant nanodipsersions using proniosome technology and high-pressure homogenization.

In this study, a niosome nanodispersion was manufactured using high-pressure homogenization following the hydration of proniosomes. Using beclometasone dipropionate (BDP) as a model drug, the characteristics of the homogenized niosomes were compared with vesicles prepared via the conventional approach of probe-sonication. Particle size, zeta potential, and the drug entrapment efficiency were similar for both size reduction mechanisms. However, high-pressure homogenization was much more efficient than sonication in terms of homogenization output rate, avoidance of sample contamination, offering a greater potential for a large-scale manufacturing of noisome nanodispersions. For example, high-pressure homogenization was capable of producing small size niosomes (209 nm) using a short single-step of size reduction (6 min) as compared with the time-consuming process of sonication (237 nm in >18 min) and the BDP entrapment efficiency was 29.65% ± 4.04 and 36.4% ± 2.8. In addition, for homogenization, the output rate of the high-pressure homogenization was 10 ml/min compared with 0.83 ml/min using the sonication protocol. In conclusion, a facile, applicable, and highly efficient approach for preparing niosome nanodispersions has been established using proniosome technology and high-pressure homogenization.

Thymopentin nanoparticles engineered with high loading efficiency, improved pharmacokinetic properties, and enhanced immunostimulating effect using soybean phospholipid and PHBHHx polymer.

Formulation of protein and peptide drugs with sustained release properties is crucial to enhance their therapeutic effect and minimize administration frequency. In this study, immunomodulating polymeric systems were designed by manufacturing PHBHHx nanoparticles (NPs) containing thymopentin (TP5). The release profile of the drug was studied over a period of 7 days. The PHBHHx NPs containing TP5-phospholipid (PLC) complex (TP5-PLC) displayed a spherical shape with a mean size, zeta potential, and encapsulation efficiency of 238.9 nm, -32.0 mV, and 72.81%, respectively. The cytotoxicity results showed the PHBHHx NPs had a relatively low toxicity in vitro. TP5 entrapped in the NPs could hardly release in vitro, while the NPs had longer than 7 days release duration after a single subcutaneous injection in Wistar rats. The immunodepression rat model was built to evaluate the immunomodulating effects of TP5-PLC-NPs in vivo. The results of T-lymphocyte subsets (CD3(+), CD4(+), CD8(+), and CD4(+)/CD8(+) ratio) analysis and superoxide dismutase (SOD) values suggested that TP5-PLC-NPs had stronger immunoregulation effects than TP5 solution. In conclusion, an applicable approach to markedly enhancing the loading of a water-soluble peptide into a hydrophobic polymer matrix has been introduced. Thus, TP5-PLC-NPs are promising nanomedicine systems for sustained release effects of TP5.

Targeted paclitaxel delivery to tumors using cleavable PEG-conjugated solid lipid nanoparticles.

PURPOSE: To develop a tumor-targeted drug delivery system based on solid lipid nanoparticles (SLNs) conjugated with the enzymatically cleavable polyethylene glycol (PEG). METHODS: SLNs loaded with paclitaxel (PTX) were prepared using the film ultrasonication method, followed by conjugation with a PEGylated peptide (Pp) that can specifically interact with matrix metalloproteinases (MMPs) that is over-expressed by tumor cells. The physicochemical characteristics of the Pp-PTX-SLNs were studied and the in vitro drug release, cytotoxicity and cell uptake of the formulations were investigated. Furthermore, using an animal model, the pharmacokinetic properties, biodistribution and anti-tumor activity of this system were evaluated. RESULTS: The resulting Pp-PTX-SLNs penetrated through tumor cells via facilitated uptake mediated by MMPs. The uncleavable Pp'-PTX-SLNs showed a lower cell uptake efficiency, compared with the Pp-PTX-SLNs. In a tumor-bearing mice model, Pp-PTX-SLNs accumulated to a greater extent at the tumor location, persisted longer in blood circulation, and showed lower toxicity than did PTX-SLNs or Taxol®. Most importantly, the mice treated with Pp-PTX-SLNs survived longer than the groups treated with Pp'-PTX-SLNs, PTX-SLNs or Taxol®. CONCLUSIONS: These results suggest that Pp-PTX-SLNs hold promise as a new strategy for paclitaxel chemotherapy, and that Pp-SLNs can be a useful nanocarrier for other chemotherapeutic drugs.

Stability of parenteral nanoemulsions loaded with paclitaxel: the influence of lipid phase composition, drug concentration and storage temperature.

Paclitaxel was loaded into licensed parenteral nutrition nanoemulsions (Clinoleic® and Intralipid®) using bath sonication, and the stability of the formulations was investigated following storage for two weeks at room temperature or at 4 °C. In general, Clinoleic droplets were smaller than Intralipid droplets, being around 255 and 285 nm, respectively, for blank and freshly loaded emulsions. Regardless of storage temperature, the Clinoleic exhibited a very slight or no increase in droplet size upon storage, whilst the droplet size of the Intralipid emulsion increased significantly. The droplet size of both emulsions was minimally affected by paclitaxel concentration within the range of 0, 1, 3 and 6 mg/ml. The pH of both emulsions markedly decreased upon storage at room temperature, which was possibly attributed to the production of fatty acids resulting from phospholipid hydrolysis. However, at 4 °C, the pH of Clinoleic emulsion was unaffected by storage or paclitaxel concentration while the Intralipid emulsion demonstrated a trend for pH reduction. Both nanoemulsions had a negative zeta potential, with the Clinoleic formulations having the highest charge, possibly explaining the better size stability of this emulsion. Overall, this study has shown that paclitaxel was successfully loaded into clinically licensed parenteral emulsions and that Clinoleic showed greater stability than the Intralipid.

Anticancer drug delivery: Investigating the impacts of viscosity on lipid-based formulations for pulmonary targeting.

Pulmonary drug delivery via aerosolization is a non-intrusive method for achieving localized and systemic effects. The aim of this study was to establish the impact of viscosity as a novel aspect (i.e., low, medium and high) using various lipid-based formulations (including liposomes (F1-F3), transfersomes (F4-F6), micelles (F7-F9) and nanostructured lipid carriers (NLCs; F10-F12)) as well as to investigate their impact on in-vitro nebulization performance using Trans-resveratrol (TRES) as a model anticancer drug. Based on the physicochemical properties, micelles (F7-F9) elicited the smallest particle size (12-174 nm); additionally, all formulations tested exhibited high entrapment efficiency (>89 %). Through measurement using capillary viscometers, NLC formulations exhibited the highest viscosity (3.35-10.04 m2/sec). Upon using a rotational rheometer, formulations exhibited shear-thinning (non-Newtonian) behaviour. Air jet and vibrating mesh nebulizers were subsequently employed to assess nebulization performance using an in-vitro model. Higher viscosity formulations elicited a prolonged nebulization time. The vibrating mesh nebulizer exhibited significantly higher emitted dose (ED), fine particle fraction (FPF) and fine particle dose (FPD) (up to 97 %, 90 % and 64 µg). Moreover, the in-vitro release of TRES was higher at pH 5, demonstrating an alignment of the release profile with the Korsmeyer-Peppas model. Thus, formulations with higher viscosity paired with a vibrating mesh nebulizer were an ideal combination for delivering and targeting peripheral lungs.