Oil-Filled Lipid Nanoparticles Containing 2′-(2-Bromohexadecanoyl)-Docetaxel for the Treatment of Breast Cancer

A docetaxel (DX) lipid conjugate 2’-(2-bromohexadecanoyl)-docetaxel (2-Br-C16-DX) is synthesized to enhance the drug loading, entrapment and retention in liquid oil-filled lipid nanoparticles (NPs). The conjugate is successfully entrapped in the previously optimized NPs with an entrapment efficiency of 56.8%. In-vitro release studies in 100% mouse plasma show an initial 45% burst release with no additional release within 8 hr. The conjugate is able to be hydrolyzed to release DX by esterases in-vitro. The conjugate is less potent than unmodified DX in DU-145 and 4T1 cells. However, NPs containing the conjugate show significantly higher cytotoxicity compared to its free form especially in 4T1 cells. In-vivo, the AUC0-∞ value of NP-formulated 2-Br-C16-DX is about 100-fold higher than DX formulated in Taxotere. Furthermore, 2-Br-C16-DX NPs improve DX AUC 4.3-fold compared to Taxotere. The high concentration and prolonged exposure of both 2-Br-C16-DX and DX from 2-Br-C16-DX NPs in circulation result in a 10-fold and 1.5-fold higher accumulation of 2-Br-C16-DX and DX, respectively, in tumors compared to Taxotere. In mice bearing syngeneic 4T1 tumors, 2-Br-C16-DX NPs show markedly greater anticancer efficacy as well as survival benefit over all controls. The results of these studies support that the oil-filled NPs containing hydrolyzable lipophilic DX prodrug 2-Br-C16-DX improve the therapeutic index of DX and are more efficacious in the treatment of breast cancer

Antibacterial effects of blackberry extract target periodontopathogens: Blackberry extract targets periodontopathogens

Antimicrobial agents provide valuable adjunctive therapy for prevention and control of oral diseases. Limitations in their prolonged use have stimulated the search for new natural occurring agents with more specific activity and fewer adverse effects. Here we sought to determine the anti-bacterial properties of blackberry extract (BBE) in vitro against oral bacterial commensals and periodontopathogens

Tresyl-based conjugation of protein antigen to lipid nanoparticles increases antigen immunogenicity

The present studies were aimed at investigating the engineering of NPs with protein-conjugated-surfactant at their surface. In order to increase the immunogenicity of a protein antigen, Brij 78 was functionalized by tresyl chloride and then further reacted with the primary amine of the model proteins ovalbumin (OVA) or horseradish peroxide (HRP). The reaction yielded Brij 78-OVA and Brij 78-HRP conjugates which were then used directly to form NP-OVA or NP-HRP using a one-step warm oil-in-water microemulsion precursor method with emulsifying wax as the oil phase, and Brij 78 and the Brij 78-OVA or Brij 78-HRP conjugate as surfactants. Similarly, Brij 700 was conjugated to HIV p24 antigen to yield Brij 700-p24 conjugate. The utility of these NPs for enhancing the immune responses to protein-based vaccines was evaluated in vivo using ovalbumin (OVA) as model protein and p24 as a relevant HIV antigen. In separate in vivo studies, female BALB/c mice were immunized by subcutaneous (s.c.) injection with NP-OVA and NP-p24 formulations along with several control formulations. These results suggested that with multiple antigens, covalent attachment of the antigen to the NP significantly enhanced antigen-specific immune responses. This facile covalent conjugation and incorporation method may be utilized to further incorporate other protein antigens, even multiple antigens, into an enhanced vaccine delivery system

Development of new lipid-based paclitaxel nanoparticles using sequential simplex optimization

The objective of these studies was to develop Cremophor-free lipid-based paclitaxel (PX) nanoparticle formulations prepared from warm microemulsion precursors. To identify and optimize new nanoparticles, experimental design was performed combining Taguchi array and sequential simplex optimization. The combination of Taguchi array and sequential simplex optimization efficiently directed the design of paclitaxel nanoparticles. Two optimized paclitaxel nanoparticles (NPs) were obtained: G78 NPs composed of glyceryl tridodecanoate (GT) and polyoxyethylene 20-stearyl ether (Brij 78), and BTM NPs composed of Miglyol 812, Brij 78 and D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS). Both nanoparticles successfully entrapped paclitaxel at a final concentration of 150 μg/ml (over 6% drug loading) with particle sizes less than 200 nm and over 85% of entrapment efficiency. These novel paclitaxel nanoparticles were stable at 4°C over three months and in PBS at 37°C over 102 hours as measured by physical stability. Release of paclitaxel was slow and sustained without initial burst release. Cytotoxicity studies in MDA-MB-231 cancer cells showed that both nanoparticles have similar anticancer activities compared to Taxol®. Interestingly, PX BTM nanocapsules could be lyophilized without cryoprotectants. The lyophilized powder comprised only of PX BTM NPs in water could be rapidly rehydrated with complete retention of original physicochemical properties, in-vitro release properties, and cytotoxicity profile. Sequential Simplex Optimization has been utilized to identify promising new lipid-based paclitaxel nanoparticles having useful attributes

Formulating a Sulfonated Antiviral Dendrimer in a Vaginal Microbicidal Gel Having Dual Mechanisms of Action

SPL7013 is the sodium salt of a sulfonated dendrimer that has potent antiviral properties. VivaGel®, a topical gel containing 3% w/w SPL7013, has been shown to be safe and well-tolerated in human clinical studies. BufferGel® is a Carbopol®-based acidic buffering gel that enhances the natural protective action of the vagina to produce a broad-spectrum microbicidal environment. The positive attributes of both gels were combined into a combination vaginal microbicidal gel having dual mechanisms of action. A 3% w/w SPL7013 combination gel, pH 3.7, was developed and fully characterized, and was shown to have more than 2-fold greater acidic buffering capacity than BufferGel. Ultracentrifugation experiments demonstrated that SPL7013 was not sequestered or entropically trapped in the viscous gel, thereby confirming, along with viral challenge studies, that SPL7013 has sufficient mobility in the viscous gel to exert antiviral properties

Doxorubicin and Paclitaxel-Loaded Lipid-Based Nanoparticles Overcome Multidrug Resistance by Inhibiting P-Glycoprotein and Depleting ATP

To test the ability of nanoparticle (NP) formulations to overcome P-gp-mediated multidrug resistance (MDR), several different doxorubicin (Dox) and paclitaxel (PX)-loaded solid lipid NPs were prepared. Dox NPs showed 6-8-fold lower IC50 values in Pgp overexpressing human cancer cells than those of free Dox. The IC50 value of PX NPs was over 9-fold lower than that of Taxol® in P-gp-overexpressing cells. A series of in-vitro cell assays were used including quantitative studies on uptake and efflux, inhibition of calcein acetoxymethylester (Calcein AM) efflux, alteration of ATP levels, membrane integrity, mitochondrial membrane potential, apoptosis and cytotoxicity. Enhanced uptake and prolonged retention of Dox were observed with NP-based formulations in P-gp-overexpressing cells. Calcein AM and ATP assays confirmed that blank NPs inhibited P-gp and transiently depleted ATP. Intravenous injection of pegylated PX BTM NPs showed marked anticancer efficacy in nude mice bearing resistant NCI/ADR-RES tumors versus all control groups. NPs may be used to both target drug and biological mechanisms to overcome MDR via P-gp inhibition and ATP depletion

Effects of a Topically Applied Bioadhesive Berry Gel on Loss of Heterozygosity Indices in Premalignant Oral Lesions

The aim of this study was to assess the effects of topical application of a 10% (w/w) freeze-dried black raspberry (FBR) gel on oral intraepithelial neoplasia (IEN) variables that included histologic diagnoses and loss of heterozygosity (LOH) indices. Microsatellite instability and/or LOH at tumor suppressor gene – associated chromosomal loci have been associated with a higher risk for oral IEN progression to oral squamous cell carcinoma. Previously, our laboratories have shown that FBRs are well tolerated and possess potent antioxidant, apoptotic, and differentiation-inducing properties

Topical Application of a Bioadhesive Black Raspberry Gel Modulates Gene Expression and Reduces Cyclooxygenase 2 Protein in Human Premalignant Oral Lesions

Reduced expression of proapoptotic and terminal differentiation genes in conjunction with increased levels of the proinflammatory and angiogenesis-inducing enzymes, cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS), correlate with malignant transformation of oral intraepithelial neoplasia (IEN). Accordingly, this study investigated the effects of a 10% (w/w) freeze-dried black raspberry gel on oral IEN histopathology, gene expression profiles, intraepithelial COX-2 and iNOS proteins, and microvascular densities. Our laboratories have shown that freeze-dried black raspberries possess antioxidant properties and also induce keratinocyte apoptosis and terminal differentiation. Oral IEN tissues were hemisected to provide samples for pretreatment diagnoses and establish baseline biochemical and molecular variables. Treatment of the remaining lesional tissue (0.5 g gel applied four times daily for 6 weeks) began 1 week after the initial biopsy. RNA was isolated from snap-frozen IEN lesions for microarray analyses, followed by quantitative reverse transcription-PCR validation. Additional epithelial gene-specific quantitative reverse transcription-PCR analyses facilitated the assessment of target tissue treatment effects. Surface epithelial COX-2 and iNOS protein levels and microvascular densities were determined by image analysis quantified immunohistochemistry. Topical berry gel application uniformly suppressed genes associated with RNA processing, growth factor recycling, and inhibition of apoptosis. Although the majority of participants showed posttreatment decreases in epithelial iNOS and COX-2 proteins, only COX-2 reductions were statistically significant. These data show that berry gel application modulated oral IEN gene expression profiles, ultimately reducing epithelial COX-2 protein. In a patient subset, berry gel application also reduced vascular densities in the superficial connective tissues and induced genes associated with keratinocyte terminal differentiation

Ultra-long-acting removable drug delivery system for HIV treatment and prevention

Non-adherence to medication is an important health care problem, especially in the treatment of chronic conditions. Injectable long-acting (LA) formulations of antiretrovirals (ARVs) represent a viable alternative to improve adherence to HIV/AIDS treatment and prevention. However, the LA-ARV formulations currently in clinical trials cannot be removed after administration even if adverse events occur. Here we show an ultra-LA removable system that delivers drug for up to 9 months and can be safely removed to stop drug delivery. We use two pre-clinical models for HIV transmission and treatment, non-human primates (NHP) and humanized BLT (bone marrow/liver/thymus) mice and show a single dose of subcutaneously administered ultra-LA dolutegravir effectively delivers the drug in both models and show suppression of viremia and protection from multiple high-dose vaginal HIV challenges in BLT mice. This approach represents a potentially effective strategy for the ultra-LA drug delivery with multiple possible therapeutic applications

Nonaqueous Gel for the Transdermal Delivery of a DTPA Penta-ethyl Ester Prodrug

Diethylenetriamine pentaacetic acid penta-ethyl ester, designated as C2E5, was successfully incorporated into a nonaqueous gel for transdermal delivery. The thermal and rheological properties of a formulation containing 40% C2E5, 20% ethyl cellulose, and 40% Miglyol 840® prepared using the solvent evaporation method demonstrated that the gel had acceptable content uniformity and flow properties. In vitro studies showed that C2E5 was steadily released from the gel at a rate suitable for transdermal delivery. Topical application of the gel at a 200 mg C2E5/kg dose level in rats achieved significantly higher plasma exposures of several active metabolites compared with neat C2E5 oil at the same dose level. The results suggest that transdermal delivery of a chelator prodrug is an effective radionuclide decorporation strategy by delivering chelators to the circulation with a pharmacokinetic profile that is more consistent with the biokinetic profile of transuranic elements in contaminated individuals