Microphase separation in binary polymeric micelles

1988 ◽  
Vol 49 (1) ◽  
pp. 131-137 ◽  
Author(s):  
A. Halperin
Author(s):  
Richard J. Spontak ◽  
Steven D. Smith ◽  
Arman Ashraf

Block copolymers are composed of sequences of dissimilar chemical moieties covalently bonded together. If the block lengths of each component are sufficiently long and the blocks are thermodynamically incompatible, these materials are capable of undergoing microphase separation, a weak first-order phase transition which results in the formation of an ordered microstructural network. Most efforts designed to elucidate the phase and configurational behavior in these copolymers have focused on the simple AB and ABA designs. Few studies have thus far targeted the perfectly-alternating multiblock (AB)n architecture. In this work, two series of neat (AB)n copolymers have been synthesized from styrene and isoprene monomers at a composition of 50 wt% polystyrene (PS). In Set I, the total molecular weight is held constant while the number of AB block pairs (n) is increased from one to four (which results in shorter blocks). Set II consists of materials in which the block lengths are held constant and n is varied again from one to four (which results in longer chains). Transmission electron microscopy (TEM) has been employed here to investigate the morphologies and phase behavior of these materials and their blends.


2018 ◽  
Vol 75 (6) ◽  
pp. 1305-1312
Author(s):  
Liu Zou ◽  
Shujuan Xiong ◽  
Xiangping Deng ◽  
Juan Liu ◽  
Runde Xiong ◽  
...  

Author(s):  
R S Thakur ◽  
A Nayaz ◽  
Y Koushik

In the case of solubility limited absorption, creating supersaturation in the GI fluid is very critical as supersaturation may provide great improvement of oral absorption. The techniques to create the so-called supersaturation in the GI fluid include microemulsions, emulsions, liposomes, complexations, polymeric micelles, and conventional micelles. Ciprofloxacin was chosen because it is practically insoluble in water; hence its salt form is used commercially, which is soluble in water. The objective of the present investigation was to enhance the solubility of Ciprofloxacin by formulating it into microemulsion system. For this purpose, initially, surfactant and cosurfactant were selected based on their HLB value, followed by pseudo-ternary phase diagrams to identify the microemulsion existing zone. Different formulations were developed and evaluated for pH, conductivity, in vitro release and stability. Solubility study was performed for optimized formulation. The pH of the designed formulations varied from 6.02-7.04. This was ideal and near blood pH 7.4. Conductivity data indicated that the microemulsion was of the o/w type. In vitro release of optimized formulation(FM3) was 95.2% as compared to pure drug 46.61% after 90 min and marketed product(salt form) 93.9%. Hence, by formulating into microemulsion, the solubility of ciprofloxacin is significantly enhanced.    


2019 ◽  
Vol 14 (3) ◽  
pp. 280-291 ◽  
Author(s):  
Jaleh Varshosaz ◽  
Farshid Hassanzadeh ◽  
Batool Hashemi-Beni ◽  
Mohsen Minaiyan ◽  
Saeedeh Enteshari

Background: Due to the low water solubility of Docetaxel (DTX), it is formulated with ethanol and Tween 80 with lots of side effects. For this reason, special attention has been paid to formulate it in new drug nano-carriers. Objective: The goal of this study was to evaluate the safety, antitumor activity and tissue distribution of the novel synthesized Raloxifene (RA) targeted polymeric micelles. Methods: DTX-loaded RA-targeted polymeric micelles composed of poly(styrene-maleic acid)- poly(amide-ether-ester-imide)-poly(ethylene glycol) (SMA-PAEE-PEG) were prepared and their antitumor activity was studied in MC4-L2 tumor-bearing mice compared with non-targeted micelles and free DTX. Safety of the micelles was studied by Hematoxylin and Eosin (H&E) staining of tumors and major organs of the mice. The drug accumulation in the tumor and major organs was measured by HPLC method. Results: The results showed better tumor growth inhibition and increased survival of mice treated with DTX-loaded in targeted micelles compared to the non-targeted micelles and free DTX. Histopathological studies, H&E staining of tumors and immunohistochemical examination showed the potential of DTX-loaded RA-targeted micelles to inhibit tumor cells proliferation. The higher accumulation of the DTX in the tumor tissue after injection of the micelles compared to the free DTX may indicate the higher uptake of the targeted micelles by the G-Protein-Coupled Estrogen Receptors (GPER). Conclusion: The results indicate that RA-conjugated polymeric micelles may be a strong and effective drug delivery system for DTX therapy and uptake of the drug into tumor cells, and overcome the disadvantages and side effects of conventional DTX.


2020 ◽  
Vol 13 ◽  
Author(s):  
Rohit Bhatia ◽  
Amit Sharma ◽  
Raj Kumar Narang ◽  
Ravindra K. Rawal

: Cancer is one of the most serious health concerns in 21st century whose prevalence is beyond boundaries and can affect any organ of human beings. The conventional chemotherapeutic treatment strategies lack specificity to tumours and are associated with toxic effects on immune system and other organ systems. In the past decades, there has been a continuous progress in the development of smart nanocarrier systems for target specific delivery of drugs against variety of tumours including intracellular gene-specific targeting. These nanocarriers are able to recognize the tumour cells and deliver the therapeutic agent in fixed proportions causing no or very less harm to healthy cells. Nanosystems have modified physicochemical properties, improved bioavailability and long retention in blood which enhances their potency. A huge number of nanocarrier based formulations have been developed and are in clinical trials. Nanocarrier systems include polymeric micelles, liposomes, dendrimers, carbon nanotubes, gold nanoparticles, etc. Recent advancements in nanocarrier systems include mesoporous silica nanoparticles (MSNs), metal organic frame works and quantum dots. In the present review, various nanocarrier based drug delivery systems along with their applications in the management of cancer have been described with special emphasis on MSNs.


2016 ◽  
Vol 4 (2) ◽  
pp. 109-119 ◽  
Author(s):  
Hanan Al-Lawati ◽  
Mohammad R. Vakili ◽  
Fakhreddin Jamali ◽  
Afsaneh Lavasanifar

2018 ◽  
Vol 14 (5) ◽  
pp. 1842
Author(s):  
Xuelian Guo ◽  
Zhewen Yu ◽  
Rong Jin ◽  
Aoneng Cao

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1254
Author(s):  
Lingjie Ke ◽  
Zhiguo Li ◽  
Xiaoshan Fan ◽  
Xian Jun Loh ◽  
Hongwei Cheng ◽  
...  

Drug resistance always reduces the efficacy of chemotherapy, and the classical mechanisms of drug resistance include drug pump efflux and anti-apoptosis mediators-mediated non-pump resistance. In addition, the amphiphilic polymeric micelles with good biocompatibility and high stability have been proven to deliver the drug molecules inside the cavity into the cell membrane regardless of the efflux of the cell membrane pump. We designed a cyclodextrin (CD)-based polymeric complex to deliver chemotherapeutic doxorubicin (DOX) and Nur77ΔDBD gene for combating pumps and non-pump resistance simultaneously. The natural cavity structure of the polymeric complex, which was comprised with β-cyclodextrin-graft-(poly(ε-caprolactone)-adamantly (β-CD-PCL-AD) and β-cyclodextrin-graft-(poly(ε-caprolactone)-poly(2-(dimethylamino) ethyl methacrylate) (β-CD-PCL-PDMAEMA), can achieve the efficient drug loading and delivery to overcome pump drug resistance. The excellent Nur77ΔDBD gene delivery can reverse Bcl-2 from the tumor protector to killer for inhibiting non-pump resistance. The presence of terminal adamantyl (AD) could insert into the cavity of β-CD-PCL-PDMAEMA via host-guest interaction, and the releasing rate of polymeric inclusion complex was higher than that of the individual β-CD-PCL-PDMAEMA. The polymeric inclusion complex can efficiently deliver the Nur77ΔDBD gene than polyethylenimine (PEI-25k), which is a golden standard for nonviral vector gene delivery. The higher transfection efficacy, rapid DOX cellular uptake, and significant synergetic tumor cell viability inhibition were achieved in a pump and non-pump drug resistance cell model. The combined strategy with dual drug resistance mechanisms holds great potential to combat drug-resistant cancer.


2021 ◽  
pp. 2100385
Author(s):  
Tobias A. Bauer ◽  
Natalie K. Horvat ◽  
Oriana Marques ◽  
Sara Chocarro ◽  
Christina Mertens ◽  
...  

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