Bioactive-Chylomicrons for Oral Lymphatic Targeting of Berberine Chloride: Novel Flow-Blockage Assay in Tissue-Based and Caco-2 Cell Line Models

Purpose

To develop novel bioactive-chylomicrons to solve oral delivery obstacles of Berberine chloride and target the lymphatic system.

Methods

Berberine-loaded bioactive-chylomicrons were prepared and underwent full in vitro characterization. Intestinal permeability was appraised via both non-everted gut sac model and Caco-2 cell model. Furthermore, Bioactive-chylomicrons’ cellular uptake and distribution were examined by laser scanning confocal microscopy. Finally, a novel chylomicron flow-blockage assay on tissue and cellular levels were elaborated to assess the lymphatic targeting ability.

Results

Berberine-loaded chylomicrons showed spherical vesicles of size (175.6 nm), PDI (0.229), zeta potential (?16 .6 mV) and entrapment efficiency (95.5%). Ex-vivo intestinal permeability studies demonstrated 10.5 fold enhancement in permeability of Berberine-loaded chylomicrons over free Berberine. Moreover, Caco-2 studies revealed significant improvement in chylomicrons’ permeability and cellular uptake. Furthermore, confocal microscopy analyses revealed 2 fold increase in berberine-loaded chylomicrons’ intracellular fluorescence. Lymphatic targeting models were successfully elaborated using cycloheximide protein synthesis inhibitor. Such models demonstrated 47 and 27.5% reduction in ex-vivo and Caco-2 permeability respectively. Finally, a good rank order correlation was established between different permeability assessment techniques.

Conclusion

The findings shed the light on the underlying mechanisms of Berberine bioavailability improvement. Consequently, berberine-loaded chylomicrons could be considered as promising bioactive-nanocarriers for Berberine lymphatic targeting and bioavailability improvement.

     

Biodegradable Nanoparticles Improve Oral Bioavailability of Amphotericin B and Show Reduced Nephrotoxicity Compared to Intravenous Fungizone®

Purpose

Amphotericin B (AMB), an effective antifungal and antileishmanial agent associated with low oral bioavailability (0.3%) and severe nephrotoxicity, was entrapped into poly(lactide-co-glycolide) (PLGA) nanoparticles to improve the oral bioavailability and to minimize the adverse effects associated with it.

Materials and Methods

The AMB-nanoparticles (AMB-NP) were prepared by nanoprecipitation method employing Vitamin E-TPGS as a stabilizer. In vitro release was carried out using membrane dialysis method. The in vitro hemolytic activity of AMB-NP was evaluated by incubation with red blood cells (RBCs). The acute nephrotoxicity profile and oral bioavailability of AMB-NP were evaluated in rats.

Results

The prepared AMB-NP formulation contained monodispersed particles in the size range of 165.6?±?2.9 nm with 34.5?±?2.1% entrapment at 10% w/w initial drug loading. AMB-NP formulation showed biphasic drug release, an initial rapid release followed by a sustained release. The AMB-NP formulation exerted lower hemolysis and nephrotoxicity as compared to Fungizone®. The relative oral bioavailability of the AMB-NP was found to be ～800% as compared to Fungizone®.

Conclusion

Together, these results offer a possibility of treating systemic fungal infection and leishmaniasis with oral AMB-NP, which could revolutionize the infectious disease treatment modalities.

     

Application of Lipid Blend-Based Nanoparticulate Scaffold for Oral Delivery of Antihypertensive Drug: Implication on Process Variables and In Vivo Absorption Assessment

Purpose

The aim of the present study was to formulate and optimize lipid blend-based olmesartan medoxomil (OLM) loaded nanoparticulate scaffolds (NLCs) for enhanced oral bioavailability.

Method

The OLM-NLCs were formulated using dependent variables in different concentrations of solid lipid, liquid lipid, surfactant, and co-surfactant by using melt emulsification combined with ultrasonication technique. The formulations were experimentally optimized using a three-factor, three-level statistical design approach. The formulated OLM-NLCs were evaluated for various pharmaceutical quality evaluation parameters and further optimized formulation (OLM-NLCopt) was assessed for release kinetics, thermal behavior, and in vivo absorption assessment.

Result

The optimized formulation (OLM-NLCopt) showed particle size (138.7 nm), PDI (0.18), and entrapment efficiency (83.65%). The comparative in vitro release study revealed OLM-NLCopt showed significantly higher (p?<?0.05) drug release compare to OLM-susp. The in vivo study showed the OLM-NLCopt indicated nearly 3-fold improvement in oral bioavailability vis-a-vis OLM-susp in mice model.

Conclusion

The results of the release study and pharmacokinetic study suggest the potential of OLM-NLCs for improved oral delivery.

     

Improved Stability and Enhanced Oral Bioavailability of Atorvastatin Loaded Stearic Acid Modified Gelatin Nanoparticles

Purpose

The present study evaluates the effects of stearic acid conjugation with gelatin and, its pharmaceutical potential to formulate novel atorvastatin (AT) loaded nanoparticles.

Method

AT loaded stearic acid modified gelatin nanoparticles (AT-MG NPs) were prepared via two-step desolvation method with extensive optimization of different process variables. Further, the developed nanoparticles where evaluated against in vitro Caco-2 cell model and in vivo bioavailability.

Results

Extensive optimization of nanoformulation resulted into the formation of AT-MG NPs with particle size 247.7 ± 10.9 nm, PDI 0.219 ± 0.07, and entrapment efficiency 58.7 ± 5.3%. Freeze dried nanoparticles were found to have spherical shape as determined by SEM and demonstrated excellent stability in simulated gastrointestinal conditions and during storage. Developed nanoparticles exhibited sustained release up to 24 h and remarkably higher Caco-2 cell uptake. Mechanistic studies further revealed the clathrin and caveolae mediated endocytosis as principle mechanism. In line with Caco-2 cell uptake observations, AT-MG NPs showed ～4.84-fold increase in the AUC0-∞ values of AT in comparison with free AT following oral administration.

Conclusion

Overall, the stearic acid conjugated gelatin NPs demonstrates a promising potential in improving the drug payload of BCS class II drugs and enhancing oral bioavailability.

     

A Two-way Randomized Cross-over Pharmacokinetic and Pharmacodynamic Study of an Innovative Oral Solution of Midazolam (ADV6209)

Purpose

The objective of this study was to assess the bioavailability and the sedative effect of a single-dose administration of an innovative oral solution of midazolam containing γ-cyclodextrins (ADV6209).

Methods

A bioavailability study with a standard two-sequences, two-periods, and crossover design was conducted. Subjects randomly received 15 mg of ADV6209 by oral route followed by 5 mg of the reference drug (midazolam hydrochloride intravenous solution (Hypnovel®, Roche) by intravenous route or vice versa. Blood samples were drawn at different time points to measure midazolam and its metabolite α-hydroxymidazolam concentrations. Non-compartmental pharmacokinetic methods were used to calculate main pharmacokinetic parameters and absolute bioavailability.

Results

Caucasian healthy subjects (n = 12) were included in the study. ADV6209 had a bioavailability of 39.6%. The oral elimination half-life with ADV6209 was slightly shorter than with the reference i.v. form (2.66 h versus 2.99 h). The sedative effect was observed 27.5 ± 15.5 min after oral administration for a duration of 48.5 ± 35.4 min. Double peak phenomenon was observed in 5 patients.

Conclusions

Cyclodextrins have little impact on midazolam oral bioavailability and the pharmacokinetics parameters of midazolam formulation ADV6209 are close to those reported previously.

     

Biodegradable Polymersomes as Nanocarriers for Doxorubicin Hydrochloride: Enhanced Cytotoxicity in MCF-7/ADR Cells and Prolonged Blood Circulation

Purpose

DOX is one of the most potent anticancer drugs. But its short half-life and the occurrence of multi-drug resistance (MDR) markedly limit its clinical application. To solve these problems, we develop DOX loaded polymersomes (DOX polymersomes).

Methods

An methoxy poly(ethylene glycol)-b-poly(epsilon-caprolactone) (mPEG-b-PCL) copolymer was synthesized and used to prepare DOX polymersomes. The pharmaceutical properties of DOX polymersomes were characterized. The in vitro release profile of DOX from polymersomes was investigated. The in vitro cytotoxicity and cell uptake studies were performed on MCF-7 and MCF-7/ADR cells. The in vivo pharmacokinetic profiles were investigated on Sprague–Dawley rats.

Results

DOX polymersomes had a nano-scale particle size of about 60 nm with a hydrophobic membrane about 10 nm in thickness. Release of DOX from the polymersomes took place in a sustained manner. Cell experiments showed DOX polymersomes enhanced the cytotoxicity and the intracellular accumulation of DOX in MCF-7/ADR cells, compared with free DOX. In vivo pharmacokinetic study showed the DOX polymersomes increased the bioavailability and prolonged the circulation time in rats.

Conclusions

The entrapment of DOX in biodegradable polymersomes could enhance cytotoxicity in MCF-7/ADR cells and improve its in vivo pharmacokinetic profile.

     

Controlling Release of Integral Lipid Nanoparticles Based on Osmotic Pump Technology

Purpose

To achieve controlled release of integral nanoparticles by the osmotic pump strategy using nanostructured lipid carriers (NLCs) as model nanoparticles.

Methods

NLCs was prepared by a hot-homogenization method, transformed into powder by lyophilization, and formulated into osmotic pump tablets (OPTs). Release of integral NLCs was visualized by live imaging after labeling with a water-quenching fluorescent probe. Effects of formulation variables on in vitro release characteristics were evaluated by measuring the model drug fenofibrate. Pharmacokinetics were studied in beagle dogs using the core tablet and a micronized fenofibrate formulation as references.

Results

NLCs are released through the release orifices of the OPTs as integral nanoparticles. Near zero-order kinetics can be achieved by optimizing the influencing variables. After oral administration, decreased C _max and steady drug levels for as long as over 24 h are observed. NLC-OPTs show an oral bioavailability of the model drug fenofibrate similar to that of the core tablets, which is about 1.75 folds that of a fast-release formulation.

Conclusion

Controlled release of integral NLCs is achieved by the osmotic pump strategy.

     

Development of a Clinically Relevant Dissolution Method for Metaxalone Immediate Release Formulations Based on an IVIVC Model

Purpose

The aim of the present work was to classify metaxalone according to the Biopharmaceutics Classification System (BCS), to develop a clinically relevant dissolution method that can be used to predict the oral absorption of metaxalone and to establish an in vitro-in vivo correlation (IVIVC).

Methods

Solubility of the drug was studied in different pH media and permeability studies were performed using a Caco-2 cell model. The in vitro dissolution and in vivo disposition of metaxalone from 3 different immediate release (IR) tablet formulations were investigated using USP 2 apparatus and a single dose, four-way, crossover bioequivalence study in healthy humans along with an oral solution of the drug, respectively. An IVIVC was established by using a direct, differential based method.

Results

Metaxalone has been confirmed as a Class II drug according to BCS. Bioavailability studies performed in humans demonstrated that dissolution was the rate limiting step for bioavailability of the drug and one of the test products had significantly improved bioavailability compared to the marketed product Skelaxin®. An IVIVC model was developed that demonstrated an acceptable internal predictability.

Conclusion

The IVIVC demonstrated that formulation factors play a significant role in dissolution and absorption of metaxalone. A pH 4.5 dissolution medium containing 0.5% NaCl with 0.2% SLS (USP apparatus 2 at 50 rpm) is clinically relevant to predict bioavailability of the drug and is superior to the USP method in terms of the Quality by Design (QbD) concept.

     

<Emphasis Type="BoldItalic">In Vitro</Emphasis> and <Emphasis Type="BoldItalic">In Vivo</Emphasis> Characterization of Drug Nanoparticles Prepared Using PureNano™ Continuous Crystallizer to Improve the Bioavailability of Poorly Water Soluble Drugs

Purpose

The aim of this study was to enhance the dissolution and oral absorption of poorly water-soluble active pharmaceutical ingredients (APIs) using nanoparticle suspensions prepared with a PureNano? continuous crystallizer (PCC).

Method

Nanoparticle suspensions were prepared with a PCC, which is based on microfluidics reaction technology and solvent–antisolvent crystallization. Phenytoin, bezafibrate, flurbiprofen, and miconazole were used as model APIs. These APIs were dissolved in ethanol and precipitated by the addition of water and polyvinyl alcohol. Batch crystallization (BC) using a beaker was also performed to prepare the suspensions. Both PCC and BC formulations were freeze-dried before being characterized in vitro and in vivo.

Results

The particle sizes of the nanoparticle suspensions prepared with the PCC were smaller than those prepared by BC. The dissolution rate of each API in vitro significantly increased after crystallization. Reducing the particle size of either the BC or PCC formulation led to increased API flux across Caco-2 cell monolayers. PCC preparations showed higher plasma concentrations after oral administration, demonstrating the advantages of a fast dissolution rate and increased interaction with the gastrointestinal tract owing to the smaller particle size.

Conclusions

PCC can continuously produce nanoparticle APIs and is an efficient approach for improving their oral bioavailability.

     

A Comparative Study of Orally Delivered PBCA and ApoE Coupled BSA Nanoparticles for Brain Targeting of Sumatriptan Succinate in Therapeutic Management of Migraine

Purpose

The present investigation aimed at brain targeting of sumatriptan succinate (SS) for its optimal therapeutic effect in migraine through nanoparticulate drug delivery system using poly (butyl cyanoacrylate) (PBCA) and bovine serum albumin linked with apolipoprotein E3 (BSA-ApoE).

Method

The study involved formulation optimization of PBCA nanoparticles (NPs) using central composite design for achieving minimum particle size, maximum entrapment efficiency along with sustained drug release. SS incorporated in BSA-ApoE NPs (S-AA-NP) were prepared by desolvation technique and compared with SS loaded polysorbate 80 coated optimized PBCA NPs (FP_opt) in terms of their brain uptake potential, upon oral administration in male Wistar rats. The NPs were characterized by FTIR, thermal, powder XRD and TEM analysis.

Results

The in vivo studies of FP_opt and S-AA-NP on male Wistar rats demonstrated a fairly high brain/plasma drug ratio of 9.45 and 12.67 respectively 2 h post oral drug administration. The behavioural studies on male Swiss albino mice affirmed the enhanced anti-migraine potential of S-AA-NP than FP_opt (P?<?0.001).

Conclusion

The results of this work, therefore, indicate that BSA-ApoE NPs are significantly better than polysorbate 80 coated PBCA NPs for brain targeting of SS (P?<?0.05) and also offer an improved therapeutic strategy for migraine management.

     

Formulation and <Emphasis Type="BoldItalic">In-vivo</Emphasis> Pharmacokinetic Consideration of Intranasal Microemulsion and Mucoadhesive Microemulsion of Rivastigmine for Brain Targeting

Purpose

Presence of tight junctions in blood brain barrier (BBB) pose a major hurdle for delivery of drug and severely affects adequate therapeutic concentration to reach the brain. In present work, we have selected Rivastigmine hydrogen tartrate (RHT), a reversible cholinesterase inhibitor, which exhibits extensive first-pass metabolism, resulting in limited absolute bioavailability (36%). RHT shows extremely low aqueous solubility and poor penetration, resulting in inadequate concentration reaching the brain, thus necessitating frequent oral dosing. To overcome these problems of RHT, microemulsion (ME) and mucoadhesive microemulsion (MME) of RHT were formulated for brain targeting via intranasal delivery route and compared on the basis of in vivo pharmacokinetics.

Methods

ME and MME formulations containing RHT were developed by water titration method. Characterization of ME and MME was done for various physicochemical parameters, nasal spray pattern, and in vivo pharmacokinetics quantitatively and qualitatively (gamma scintigraphy studies).

Results

The developed ME and MME were transparent having globule size approximately in the range of 53–55 nm. Pharmacokinetic studies showed higher values for C_max and DTP for intranasal RHT: CH-ME over RHT-ME, thus indicating the effect of chitosan in modulating tight junctions, thereby enhanced paracellular transport of RHT.

Conclusion

Gamma scintigraphy and in vivo pharmacokinetic study suggested enhanced RHT concentration, upon intranasal administration of RHT:CH-ME, compare with other groups administered formulations intranasally. These findings suggested the potential of non-invasive intranasal route for brain delivery, especially for therapeutics, facing challenges in oral administration.

     

Novel Formulation Strategy to Improve the Feasibility of Amifostine Administration

Purpose

Amifostine (AMF), a radioprotectant, is FDA-approved for intravenous administration in cancer patients receiving radiation therapy (XRT). Unfortunately, it remains clinically underutilized due to adverse side effects. The purpose of this study is to define the pharmacokinetic profile of an oral AMF formulation potentially capable of reducing side effects and increasing clinical feasibility.

Methods

Calvarial osteoblasts were radiated under three conditions: no drug, AMF, and WR-1065 (active metabolite). Osteogenic potential of cells was measured using alkaline phosphatase staining. Next, rats were given AMF intravenously or directly into the jejunum, and pharmacokinetic profiles were evaluated. Finally, rats were given AMF orally or subcutaneously, and blood samples were analyzed for pharmacokinetics.

Results

WR-1065 preserved osteogenic potential of calvarial osteoblasts after XRT to a greater degree than AMF. Direct jejunal AMF administration incurred a systemic bioavailability of 61.5%. Subcutaneously administrated AMF yielded higher systemic levels, a more rapid peak exposure (0.438 vs. 0.875 h), and greater total systemic exposure of WR-1065 (116,756 vs. 16,874 ng*hr/ml) compared to orally administered AMF.

Conclusions

Orally administered AMF achieves a similar systemic bioavailability and decreased peak plasma level of WR-1065 compared to intravenously administered AMF, suggesting oral AMF formulations maintain radioprotective efficacy without causing onerous side effects, and are clinically feasible.

     

Development and Characterization of the Paclitaxel loaded Riboflavin and Thiamine Conjugated Carbon Nanotubes for Cancer Treatment

Purpose

In the present investigation, we prepared and evaluated the paclitaxel loaded riboflavin and thiamine conjugated multi walled carbon nanotubes (PTX-Rf-MWCNTs and PTX-Tm-MWCNTs) for targeted delivery to cancer employing MCF-7 cancer cell lines.

Methods

The developed conjugates were characterized using FTIR, NMR spectroscopy, electron microscopy drug loading, release, stability, hemolytic, ex vivo and in vivo studies etc.

Results

The percent entrapment efficiency was found to be 87.92?±?0.48 and 82.75?±?0.47% of PTX-Tm-MWCNTs, PTX-Rf-MWCNTs, respectively. The percent hemolysis of purified MWCNTs, PTX-MWCNTs, PTX-Tm-MWCNTs and PTX-Rf-MWCNTs was found to be 20.49?±?0.97, 37.39?±?0.78, 14.61?±?0.84 and 11.17?±?0.77% respectively. The PTX-Tm-MWCNTs and PTX-Rf-MWCNTs showed more cytotoxic effect as compared to PTX and PTX-MWCNTs with PTX-Rf-MWCNTs exhibiting the maximum cytotoxic potential.

Conclusion

Thus in final outcome, we concluded that the riboflavin and thiamine conjugated MWCNTs shown great promising potential in the treatment of cancer, but more exhaustive data is needed in future.

     

Triple Drug Combination of Zidovudine,Efavirenz and Lamivudine Loaded Lactoferrin Nanoparticles: an Effective Nano First-Line Regimen for HIV Therapy

Purpose

To enhance efficacy, bioavailability and reduce toxicity of first-line highly active anti-retroviral regimen, zidovudine?+?efavirenz?+?lamivudine loaded lactoferrin nanoparticles were prepared (FLART-NP) and characterized for physicochemical properties, bioactivity and pharmacokinetic profile.

Methods

Nanoparticles were prepared using sol-oil protocol and characterized using different sources such as FE-SEM, AFM, NanoSight, and FT-IR. In-vitro and in-vivo studies have been done to access the encapsulation-efficiency, cellular localization, release kinetics, safety analysis, biodistribution and pharmacokinetics.

Results

FLART-NP with a mean diameter of 67 nm (FE-SEM) and an encapsulation efficiency of >58% for each drug were prepared. In-vitro studies suggest that FLART-NP deliver the maximum of its payload at pH5 with a minimum burst release throughout the study period with negligible toxicity to the erythrocytes plus improved in-vitro anti-HIV activity. FLART-NP has improved the in-vivo pharmacokinetics (PK) profiles over the free drugs; an average of >4fold increase in AUC and AUMC, 30% increase in the C_max, >2fold in the half-life of each drug. Biodistribution data suggest that FLART-NP has improved the bioavailability of all drugs with less tissue-related inflammation as suggested with histopathological evaluation

Conclusions

The triple-drug loaded nanoparticles have various advantages against soluble (free) drug combination in terms of enhanced bioavailability, improved PK profile and diminished drug-associated toxicity.

     

Pharmacokinetic/Pharmacodynamic Relationship of Gabapentin in a CFA-induced Inflammatory Hyperalgesia Rat Model

Purpose

Gabapentin displays non-linear drug disposition, which complicates dosing for optimal therapeutic effect. Thus, the current study was performed to elucidate the pharmacokinetic/pharmacodynamic (PKPD) relationship of gabapentin’s effect on mechanical hypersensitivity in a rat model of CFA-induced inflammatory hyperalgesia.

Methods

A semi-mechanistic population-based PKPD model was developed using nonlinear mixed-effects modelling, based on gabapentin plasma and brain extracellular fluid (ECF) time-concentration data and measurements of CFA-evoked mechanical hyperalgesia following administration of a range of gabapentin doses (oral and intravenous).

Results

The plasma/brain ECF concentration-time profiles of gabapentin were adequately described with a two-compartment plasma model with saturable intestinal absorption rate (K _m ?=?44.1 mg/kg, V _max ?=?41.9 mg/h?kg) and dose-dependent oral bioavailability linked to brain ECF concentration through a transit compartment. Brain ECF concentration was directly linked to a sigmoid E _max function describing reversal of hyperalgesia (EC _{50, plasma} ?=?16.7 μg/mL, EC _{50, brain} ?=?3.3 μg/mL).

Conclusions

The proposed semi-mechanistic population-based PKPD model provides further knowledge into the understanding of gabapentin’s non-linear pharmacokinetics and the link between plasma/brain disposition and anti-hyperalgesic effects. The model suggests that intestinal absorption is the primary source of non-linearity and that the investigated rat model provides reasonable predictions of clinically effective plasma concentrations for gabapentin.

     

Orcinol Glucoside Loaded Polymer - Lipid Hybrid Nanostructured Lipid Carriers: Potential Cytotoxic Agents against Gastric,Colon and Hepatoma Carcinoma Cell Lines

Purpose

Orcinol glucoside (OG) - loaded nanostructured lipid carrier (NLC), coated with polyethylene glycol-25/55-stearate (PEG-25/55-SA), were explored for delivering OG to improve in vitro cytotoxicity against gastrointestinal tract (GIT), colon and hepatoma carcinoma cell lines. It is being expected that the PEGylated formulations would possess the sustainability in withstanding the adverse physiological extremities like the most significant metabolic activities and phase I / II enzymatic activities in the intestines.

Methods

NLCs were prepared using tristearin, oleic acid and PEG-25/55-stearate by hot homogenization-ultrasonic dispersion; characterized by DLS, TEM, SEM, AFM, entrapment efficiency and drug loading capacity studies.

Results

NLC diameter ranged from 160 to 230 nm with negative zeta potential of ?8 to ?20 mV. TEM/SEM and AFM studies suggest spherical and smooth surface morphologies. Differential scanning calorimetry studies reveal the loss of crystallinity when OG was incorporated into the NLC. NLCs showed initial burst release, followed by sustained release of OG. PEG-NLC exhibited superior anticancer activity against GIT and also in hepatoma cancer cell lines.

Conclusions

This is the first report demonstrating a practical approach for possible oral delivery of OG in GIT and targeting hepatoma cancer, warranting further in vivo studies for superior management of GIT cancer.

     

Lipid-based Formulations for Danazol Containing a Digestible Surfactant,Labrafil M2125CS: <Emphasis Type="BoldItalic">In Vivo</Emphasis> Bioavailability and Dynamic <Emphasis Type="BoldItalic">In Vitro</Emphasis> Lipolysis

Purpose

To evaluate the use of Labrafil® M2125CS as a lipid vehicle for danazol. Further, the possibility of predicting the in vivo behavior with a dynamic in vitro lipolysis model was evaluated.

Methods

Danazol (28 mg/kg) was administered orally to rats in four formulations: an aqueous suspension, two suspensions in Labrafil® M2125CS (1 and 2 ml/kg) and a solution in Labrafil® M2125CS (4 ml/kg).

Results

The obtained absolute bioavailabilities of danazol were 1.5?±?0.8%; 7.1?±?0.6%; 13.6?±?1.4% and 13.3?±?3.4% for the aqueous suspension, 1, 2 and 4 ml Labrafil® M2125CS per kg respectively. Thus administration of danazol with Labrafil® M2125CS resulted in up to a ninefold increase in the bioavailability, and the bioavailability was dependent on the Labrafil® M2125CS dose. In vitro lipolysis of the formulations was able to predict the rank order of the bioavailability from the formulations, but not the absorption profile of the in vivo study.

Conclusions

The bioavailability of danazol increased when Labrafil® M2125CS was used as a vehicle, both when danazol was suspended and solubilized in the vehicle. The dynamic in vitro lipolysis model could be used to rank the bioavailabilities of the in vivo data.

     

Vitamin E-rich Nanoemulsion Enhances the Antitumor Efficacy of Low-Dose Paclitaxel by Driving Th1 Immune Response

Purpose

To overcome the drawbacks of high dose regimen and improve the outcomes of chemotherapy at a low dose, an immunotherapeutic nanoemulsion based combination of chemotherapeutic agent (paclitaxel) with immunomodulatory agent (vitamin E) was developed and evaluated for their antitumor effect against breast cancer.

Methods

A total of five nanoemulsions loaded with various content of vitamin E were prepared and characterized. The immunoregulatory effects of vitamin E along with the overall antitumor efficacy of vitamin E-rich nanoemulsion with a low dose of paclitaxel were investigated through in vitro and in vivo experiments.

Results

Vitamin E-rich nanoemulsion exhibited relatively narrow size distribution, high entrapment efficiency and controlled in vitro release profile. In RAW264.7 cells, vitamin E-rich nanoemulsion significantly enhanced the secretion of Th1 cytokines and down-regulated the secretion of Th2 cytokine. In a co-culture system, vitamin E-rich nanoemulsion induced a high apoptosis rate in MDA-MB-231 cells as compared with vitamin E-low nanoemulsion. Furthermore, vitamin E-rich nanoemulsion exhibited superior in vivo antitumor efficacy in comparison with Taxol and vitamin E-low nanoemulsion at a paclitaxel dose of 4 mg/kg.

Conclusions

Vitamin E-rich nanoemulsion has great potential for the treatment of breast cancers with a low dose of paclitaxel via driving Th1 immune response.

     

Inhaled Pyrazinoic Acid Esters for the Treatment of Tuberculosis

Purpose

Analog development of existing drugs and direct drug delivery to the lungs by inhalation as treatments for multiple and extensively drug resistant (MDR and XDR) tuberculosis (TB) represent new therapeutic strategies. Pyrazinamide (PZA) is critical to drug sensitive TB therapy and is included in regimens for MDR TB. However, PZA-resistant Mycobacterium tuberculosis (Mtb) strains threaten its use. Pyrazinoic acid esters (PAEs) are PZA analogs effective against Mtb in vitro, including against the most common PZA resistant strains. However, PAEs require testing for TB efficacy in animal models.

Methods

PAEs were delivered daily as aqueous dispersions from a vibrating mesh nebulizer to Mtb infected guinea pigs for 4 weeks in a regimen including orally administered first-line TB drugs.

Results

PAEs tested as a supplement to oral therapy significantly reduced the organ bacterial burden in comparison to infected, untreated control animals. Thus, PAE aerosol therapy is a potentially significant addition to the regimen for PZA resistant MDR-TB and XDR-TB treatment. Interestingly, low dose oral PZA treatment combined with standard therapy also reduced bacterial burden. This observation may be important for PZA susceptible disease treatment.

Conclusion

The present study justifies further evaluation of PZA analogs and their lung delivery to treat TB.

     

Methotrexate-Loaded Nanomixed Micelles: Formulation,Characterization, Bioavailability,Safety, and In Vitro Anticancer Study

Purpose

Methotrexate (MTX), a potent anticancer drug, shows low oral bioavailability due to its low aqueous solubility and permeability. Moreover, its multidrug resistance (MDR) in cancer and toxic effects restricts its clinical applications. The aim of the study was to prepare novel MTX-loaded Poloxamer 407 and Gelucire^®44/14 (GL44) mixed micelles (MTX-PGMM) to improve its oral bioavailability and cytotoxicity and to reduce its systemic toxicity.

Methods

MTX-PGMM was prepared by dialysis method, compared with blank or MTX-free blank mixed micelles (BMM) and aqueous dispersion of MTX (MTX-AD) with respect to morphology, size, zeta potential, entrapment efficiency, in vitro release, and in vitro cytotoxicity, bioavailability, and toxicity study in rats.

Results

The developed MTX-PGMM exhibited small particle size, good encapsulation efficiency, and good stability in media simulating the physiological conditions of the gastrointestinal tract. The MTX-PGMM micelles demonstrated sustained release, enhanced (6.5-fold) oral bioavailability, slow plasma elimination, and long circulation of MTX. Biocompatibility was also established as there were no signs of tissue toxicity. Moreover, MTX-PGMM produced higher in vitro cytotoxicity (GI₅₀ of 1.44?±?0.33 μg/mL) than free MTX (GI₅₀ 13.71?±?0.99 μg/mL) in human breast cancer MCF-7 cells.

Conclusion

Poloxamer 407 and Gelucire^®44/14 (GL44) mixed micelles are promising carriers for oral delivery of MTX and can be utilized for other Biopharmaceutical Classification System class IV anticancer drugs having poor oral bioavailability and multidrug resistance in cancer.