preparation-characterization-individual-multi-drug-loaded-physically

Preparation and Characterization of Individual and Multi-drug Loaded Physically Entrapped Polymeric Micelles

Amphiphilic block copolymers like polyethyleneglycol-block-polylactic acid (PEG-b-PLA) can self-assemble into micelles above their critical micellar ...

Oregon State University

Examine the oral absorption enhancement mechanism of cromolyn sodium by sodium N-[8-(2-hydroxybenzoyl) amino] caprylate (SNAC) by evaluating the effect of SNAC on cromolyn sodium lipophilicity and changes in Caco-2 cell membrane fluidity.

Mechanistic understanding of oral drug absorption enhancement of cromolyn sodium by an amino acid derivative.

Current clinical and preclinical anticancer formulations are limited by their use of toxic excipients and stability issues upon combining different drug formulations. We have found that poly(ethylene glycol)-block-poly(d,l lactic acid) (PEG-b-PLA) micelles can deliver multiple poorly water-soluble drugs at clinically relevant doses. Paclitaxel (PTX), etoposide (ETO), docetaxel (DCTX) and 17-allylamino-17-demethyoxygeldanamycin (17-AAG) were solubilized individually in PEG-b-PLA micelles. Combinations of PTX/17-AAG, ETO/17-AAG, DCTX/17-AAG and PTX/ETO/17-AAG were also solubilized in PEG-b-PLA micelles. PEG-b-PLA micelles were characterized in terms of drug loading, size, stability and drug release. All anticancer agents in all combinations were all solubilized at the level of mg/mL and were stable for 24 h in the 2- and 3-drug combination PEG-b-PLA micelles. The stability of the 2- and 3-drug combination PEG-b-PLA micelles was due to the presence of 17-AAG. In vitro, t(1/2) values for 2- and 3-drug combination PEG-b-PLA micelles spanned 1-5 h. PEG-b-PLA micelles offer a promising alternative for combination drug therapy without formulation related side effects.

Multi-drug loaded polymeric micelles for simultaneous delivery of poorly soluble anticancer drugs.

The purpose of this work is to evaluate biodegradable drug carriers with defined size, hydrophobicity, and surface charge density for preferential lymphatic uptake and retention for sustained regional drug delivery. PLGA-PMA:PLA-PEG (PP) nanoparticles of defined size and relative hydrophobicity were prepared by nanoprecipitation method. These were compared with PS particles of similar sizes and higher hydrophobicity. PLGA-PMA:PLGA-COOH (PC) particles at 80:20, 50:50, and 20:80 ratios were prepared by nanoprecipitation for the charge study. Particle size and zeta potential were characterized by dynamic light scattering and laser doppler anemometry, respectively. Particles were administered in vivo to rats subcutaneously. Systemic and lymph node uptake was evaluated by marker recovery. Lymphatic uptake and node retention of PP nanoparticles was shown to be inversely related to size. Lymphatic uptake and node retention of PP particles, as compared to PS particles, was shown to be inversely related to hydrophobicity. Lastly, lymphatic uptake and node retention of PC nanoparticles were directly related to the anionic charge on the particles. In vivo lymphatic uptake and retention in a rat model indicates that the 50 nm PP particles are ideal for sustained regional delivery into the lymphatics for prevention/treatment of oligometastases.

Biodegradable PLGA based nanoparticles for sustained regional lymphatic drug delivery.

Poly(ethylene glycol)-block-poly(aspartate-hydrazide) (PEG-p(Asp-Hyd)) was modified using either levulinic acid (LEV) or 4-acetyl benzoic acid (4AB) attached via hydrazone bonds. Paclitaxel (PTX) conjugated to the linkers formed PEG-p(Asp-Hyd-LEV-PTX) and PEG-p(Asp-Hyd-4AB-PTX). PEG-p(Asp-Hyd-LEV-PTX) and PEG-p(Asp-Hyd-4AB-PTX) assemble into unimodal polymeric micelles with diameters of 42 nm and 137 nm, respectively. PEG-p(Asp-Hyd-LEV-PTX) and PEG-p(Asp-Hyd-4AB-PTX) at a 1:1 and 1:5 molar ratio assemble into unimodal mixed polymeric micelles with diameters of 85 and 113 nm, respectively. PEG-p(Asp-Hyd-LEV-PTX) micelles release LEV-PTX faster at pH 5.0 than at pH 7.4 over 24 h. At pH 7.4 mixed polymeric micelles at 1:5 ratio show no difference in LEV-PTX release from PEG-p(Asp-Hyd-LEV-PTX) micelles. Mixed polymeric micelles at 1:5 molar ratio gradually release LEV-PTX at pH 5.0, with no release of 4AB-PTX. PEG-p(Asp-Hyd-LEV-PTX) micelles and mixed polymeric micelles exert comparable cytotoxicity against SK-OV-3 and MCF-7 cancer cell lines. In summary, mixed polymeric micelles based on PEG-p(Asp-Hyd-LEV-PTX) and PEG-p(Asp-Hyd-4AB-PTX) offer prospects for pH-dependent release of PTX, offering a novel prodrug strategy for adjusting its pharmacokinetic and pharmacodynamic properties for cancer therapy. If successful this delivery system offers an alternative new mode of delivery for paclitaxel with a new scope for its efficacy along with a minimal synthetic framework needed to accomplish this.

Polymeric micelles for the pH-dependent controlled, continuous low dose release of paclitaxel.

The effect of novel surfactants on the aqueous solubility and the permeability of paclitaxel across a Caco-2 cell monolayer were examined in this work. The solubility and permeability of paclitaxel was evaluated in the presence of four soft surfactants (SS) KXN441, KXN424, KXN437, and KXN 337 and Solutol HS15. All surfactants increased the aqueous solubility of paclitaxel. Caco-2 cell membrane integrity in the presence of SS and Solutol HS15 was assessed by mannitol permeability and LDH release. All surfactants were tested at 0.5x CMC, 5x CMC and 1.5 mM concentrations. The effect of SSs on paclitaxel permeability was concentration dependent. At all concentrations tested, KXN 441 and Solutol HS 15 showed partially inhibition of drug efflux with no discernable change in mannitol permeability or cytotoxicity as observed with LDH release. At these concentrations, other SSs exhibited some partial efflux inhibition along with compromised membrane integrity and increasing mannitol permeability. In conclusion, all SSs were able to increase the aqueous solubility and permeability of paclitaxel across Caco-2 cells monolayer. However, KXN441 and Solutol HS15 were able to enhance paclitaxel permeability across Caco-2 monolayer without cytotoxicity.

The effect of novel surfactants and Solutol HS 15 on paclitaxel aqueous solubility and permeability across a Caco-2 monolayer.

To prepare mixed polymeric micelles that can carry two different drugs, doxorubicin (DOX) and 17-hydroxyethylamino-17-demethoxygeldanamycin (GDM-OH), for combination cancer chemotherapy.

Mixed pH-sensitive polymeric micelles for combination drug delivery.

Poly(ethylene glycol)-block-poly(D,L-lactic acid) (PEG-b-PLA) micelles have a proven capacity for drug solubilization and have entered phase III clinical trials as a substitute for Cremophor EL in the delivery of paclitaxel in cancer therapy. PEG-b-PLA is less toxic than Cremophor EL, enabling a doubling of paclitaxel dose in clinical trials. We show that PEG-b-PLA micelles act as a 3-in-1 nanocontainer for paclitaxel, 17-allylamino-17-demethoxygeldanamycin (17-AAG), and rapamycin for multiple drug solubilization. 3-in-1 PEG-b-PLA micelles were ca. 40 nm in diameter; dissolved paclitaxel, 17-AAG, and rapamycin in water at 9.0 mg/mL; and were stable for 24 h at 25 °C. The half-life for in vitro drug release (t(1/2)) for 3-in-1 PEG-b-PLA micelles was 1-15 h under sink conditions and increased in the order of 17-AAG, paclitaxel, and rapamycin. The t(1/2) values correlated with log P(o/w) values, implicating a diffusion-controlled mechanism for drug release. The IC(50) value of 3-in-1 PEG-b-PLA micelles for MCF-7 and 4T1 breast cancer cell lines was 114 ± 10 and 25 ± 1 nM, respectively; combination index (CI) analysis showed that 3-in-1 PEG-b-PLA micelles exert strong synergy in MCF-7 and 4T1 breast cancer cell lines. Notably, concurrent intravenous (iv) injection of paclitaxel, 17-AAG, and rapamycin using 3-in-1 PEG-b-PLA micelles was well-tolerated by FVB albino mice. Collectively, these results suggest that PEG-b-PLA micelles carrying paclitaxel, 17-AAG, and rapamycin will provide a simple yet safe and efficacious 3-in-1 nanomedicine for cancer therapy.

A 3-in-1 polymeric micelle nanocontainer for poorly water-soluble drugs.

Angiogenesis is an essential process for disease progression in many solid tumors. There are several major cascade events in the angiogenic process that can be targeted to inhibit new blood vessel formation in the tumor tissue. The purpose of this work is to evaluate the inhibitory effect of paclitaxel (PTX) and rapamycin (RAP) as individual and in dual drug-loaded poly(ethylene glycol)-block-poly(d,l-lactic acid) (PEG-b-PLA) micelles on the angiogenic cascade processes of proliferation, migration, and tube formation. PEG-b-PLA PTX and/or RAP micelles were formed and characterized for size and drug loading. Sizes of individual and dual drug micelles were below 40 nm. PEG-b-PLA micelles significantly enhanced the aqueous solubility of PTX 1.80 mg/mL and RAP 1.60 mg/mL. The PTX-RAP dual drug PEG-b-PLA micelles were able to load PTX and RAP at 1.60 mg/mL for both drugs. Cell proliferation, apoptosis, tubule formation, and migration studies were performed in human umbilical vein endothelial cells (HUVEC). PTX and RAP in DMSO inhibited HUVEC proliferation with IC50 values of 0.82 ± 0.02 and 13 829 ± 681 nM, respectively, while the combination of both drugs in DMSO produced synergistic inhibition. PTX and RAP individual micelles had IC50 values of 6.3 ± 1.1 and 14 051 ± 821 nM, respectively. PTX and dual drug micelles had a synergistic inhibition effect on HUVEC proliferation through the induction of apoptosis via caspase 3/7 activity. In vitro tube formation assay demonstrated significant inhibition of tube formation upon treatment with dual drug micelles as compared to individual PTX or RAP micelles. Migration studies in HUVEC have shown that individual PTX micelles inhibited cell migration at 1 nM, while RAP micelles did not show any inhibitory effect on cell migration. Interestingly, the presence of RAP in the dual drug micelles was able to initiate the inhibition of the migration of HUVEC at 0.1 nM concentration of PTX. These results indicate that PTX-RAP dual drug micelles have antiangiogenic effects in vitro mediated through three major events in the angiogenic process and have strong potential for further development as antiangiogenic chemotherapy.

Inhibitory effect of paclitaxel and rapamycin individual and dual drug-loaded polymeric micelles in the angiogenic cascade.

The in vitro inhibitory effect of Docetaxel (DTX) and Everolimus (EVR) alone and together in poly(ethylene glycol)-block-poly(D,L-lactic acid) (PEG-b-PLA) nanocarriers on angiogenic processes and acute toxicity in mice was evaluated.

Antiangiogenic effect of docetaxel and everolimus as individual and dual-drug-loaded micellar nanocarriers.

Non-ionic surfactant vesicles, simply known as niosomes are synthetic vesicles with potential technological applications. Niosomes have the same potential advantages of phospholipid vesicles (liposomes) of being able to accommodate both water soluble and lipid soluble drug molecules control their release and as such serve as versatile drug delivery devices of numerous applications. Additionally, niosomes can be considered as more economically, chemically, and occasionally physically stable alternatives to liposomes. Niosomes can be fabricated using simple methods of preparations and from widely used surfactants in pharmaceutical technology. Many reports have discussed niosomes in terms of physicochemical properties and their applications as drug delivery systems. In this report, a brief and simplified summary of different theories of self-assembly will be given. Furthermore manufacturing methods, physical characterization techniques, bilayer membrane additives, unconventional niosomes (discomes, proniosomes, elastic and polyhedral niosomes), their recent applications as drug delivery systems, limitations and directions for future research will be discussed.

Recent advances in non-ionic surfactant vesicles (niosomes): self-assembly, fabrication, characterization, drug delivery applications and limitations.

Biodegradable poly(ethyleneglycol)-poly(valerolactone)-poly(ethyleneglycol) [PEG-PVL-PEG] copolymers were synthesized through ring opening polymerization of δ-valerolactone (VL) followed by the coupling of monomethoxy poly(ethyleneglycol-poly(valerolactone) (mPEG-PVL) with hexamethylene diisocyanate (HDI). The copolymers were characterized by (1)H NMR, FT-IR, and GPC. Block copolymers of PEG and PVL with different VL/PEG molar ratios were successfully synthesized. One of the copolymers (Copolymer 2, PEG550-PVL6768-PEG550) displayed a sol-gel transition at a physiological temperature based on the test tube inverting method and rheological studies. The thermogelling copolymer demonstrated a characteristic crystalline peak for PVL block as determined by DSC and XRD analysis. In vitro release from the copolymer hydrogel matrix indicated that dexamethasone (DEX), a hydrophobic model drug, released comparatively slower than 5-fluoruracil (5-FU), a hydrophilic model drug, due to the potential partitioning of DEX into the PVL core. 5-FU in vitro release from copolymer 2 was 86% in 22 h, whereas only 14% of DEX was released in 24h. Cell viability studies confirmed that hydrogels composed of block copolymers are biocompatible. Copolymer 2 showed more than 80% relative cell viability at all concentrations, including concentrations greater than 200 fold CMC. In vivo gel formation studies indicate that gel integrity was maintained for 7 days upon subcutaneous injection into mice. These results indicate that PEG-PVL-PEG copolymers are suitable for drug delivery applications.

In situ gelling polyvalerolactone-based thermosensitive hydrogel for sustained drug delivery.

The solid-state interactions of fused mixtures nimesulide (ND) with polyethylene glycol (PEG) 4000, urea or mannitol were studied through constructing thaw-melt phase equilibrium diagrams.

Eutectic, monotectic and immiscibility systems of nimesulide with water-soluble carriers: phase equilibria, solid-state characterisation and in-vivo/pharmacodynamic evaluation.

The development of safe and convenient drug delivery strategies for treatment of posterior segment eye diseases is challenging. Although intravitreal injection has wide acceptance amongst clinicians, its use is associated with serious side-effects. Recently, the suprachoroidal space (SCS) has attracted the attention of ophthalmologists and pharmaceutical formulators as a potential site for drug administration and delivery to the posterior segment of the eye. This review highlights the major constraints of drug delivery to the posterior eye segment, key anatomical and physiological features of the SCS and drug delivery applications of this route with emphasis on microneedles along with future perspectives.

The suprachoroidal pathway: a new drug delivery route to the back of the eye.

Doxorubicin hydrochloride (ADR) is an anthracycline antibiotic used to treat various cancers. However, due to its extensive cardiotoxic side effects a lifetime cumulative dose limit of 450-550mg/m2 exists. The postulated mechanism of the cardiotoxicity is generation of reactive oxygen and nitrogen species. Natural products like resveratrol (RES), and quercetin (QUE) are known free radical scavengers and have shown cardioprotective effects. However, concurrent dosing of these natural products with ADR is limited due to their low solubility, and low oral bioavailability. We hypothesize that the combination of RES and QUE in Pluronic® F127 micelles (mRQ) when co-administered with ADR, will be cardioprotective in vitro and in vivo, while maintaining or increasing the efficacy of ADR against cancer cell lines in vitro. We prepared mRQ micelles capable of retaining 1.1mg/mL and 1.42mg/mL of RES and QUE respectively. The in vitro release of RES and QUE from the micelles followed first order kinetics over 48h. In vitro cell viability and combination index analysis studies in human ovarian cancer cells (SKOV-3) and rat cardiomyocytes (H9C2) showed that RES:QUE: ADR at 10:10:1 ratio was synergistic in SKOV-3 cells and antagonistic in H9C2 cells. Caspase 3/7 activity studies indicated that mRQ did not interfere with ADR caspase activity in SKOV-3 cells but significantly decreased it in H9C2 cells. The generation of reactive oxygen species (ROS) in SKOV-3 and H9C2 cells in the presence of mRQ also indicated no changes in ROS activity in SKOV-3 cells but significant scavenging in H9C2 cells. Healthy mice were exposed to acute doses of ADR and ADR with mRQ. Based on biochemical estimations the presence of mRQ with ADR conferred full cardioprotection in these mice. Concurrent administration of mRQ with ADR at 10:10:1 ratio provides a viable strategy to mitigate acute ADR induced cardiotoxicity.

Article	Year
Mechanistic understanding of oral drug absorption enhancement of cromolyn sodium by an amino acid derivative. Pharmaceutical research\| PubMed ID: 17846867	2008
Multi-drug loaded polymeric micelles for simultaneous delivery of poorly soluble anticancer drugs. Journal of controlled release : official journal of the Controlled Release Society\| PubMed ID: 19409432	2009
Biodegradable PLGA based nanoparticles for sustained regional lymphatic drug delivery. Journal of pharmaceutical sciences\| PubMed ID: 19902520	2010
Polymeric micelles for the pH-dependent controlled, continuous low dose release of paclitaxel. Biomaterials\| PubMed ID: 19959225	2010
The effect of novel surfactants and Solutol HS 15 on paclitaxel aqueous solubility and permeability across a Caco-2 monolayer. Journal of pharmaceutical sciences\| PubMed ID: 20198687	2010
Mixed pH-sensitive polymeric micelles for combination drug delivery. Pharmaceutical research\| PubMed ID: 20700632	2010
A 3-in-1 polymeric micelle nanocontainer for poorly water-soluble drugs. Molecular pharmaceutics\| PubMed ID: 21630670	2011
Inhibitory effect of paclitaxel and rapamycin individual and dual drug-loaded polymeric micelles in the angiogenic cascade. Molecular pharmaceutics\| PubMed ID: 23590802	2013
Antiangiogenic effect of docetaxel and everolimus as individual and dual-drug-loaded micellar nanocarriers. Pharmaceutical research\| PubMed ID: 24065590	2014
Recent advances in non-ionic surfactant vesicles (niosomes): self-assembly, fabrication, characterization, drug delivery applications and limitations. Drug delivery\| PubMed ID: 24156390	2014
In situ gelling polyvalerolactone-based thermosensitive hydrogel for sustained drug delivery. European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft für Pharmazeutische Verfahrenstechnik e.V\| PubMed ID: 24931340	2014
Eutectic, monotectic and immiscibility systems of nimesulide with water-soluble carriers: phase equilibria, solid-state characterisation and in-vivo/pharmacodynamic evaluation. The Journal of pharmacy and pharmacology\| PubMed ID: 24944002	2014
The suprachoroidal pathway: a new drug delivery route to the back of the eye. Drug discovery today\| PubMed ID: 25448755	2015
Combinatorial resveratrol and quercetin polymeric micelles mitigate doxorubicin induced cardiotoxicity in vitro and in vivo. Journal of controlled release : official journal of the Controlled Release Society\| PubMed ID: 26160305	2015

Adam W. G. Alani

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