scholarly journals Self-assembled sorbitol-derived supramolecular hydrogels for the controlled encapsulation and release of active pharmaceutical ingredients

2015 ◽  
Vol 51 (35) ◽  
pp. 7451-7454 ◽  
Author(s):  
Edward J. Howe ◽  
Babatunde O. Okesola ◽  
David K. Smith

A simple supramolecular hydrogel is able to extract acid-functionalised anti-inflammatory drugs via directed interactions with the self-assembled gel nanofibres and exhibits pH-controlled drug release.

2020 ◽  
Vol 17 (10) ◽  
pp. 743-748
Author(s):  
Sultan Pathan ◽  
Anil Repale ◽  
Girdhar Pal

Celecoxib containing pyrazole derivatives were synthesized by path aldol condensation of substituted ketone with trifluoroethyl acetate subsequently by cyclization of the formed chalcones with 4-methanesulfonylphenylhydrazine. Here, a one-pot synthesis of celecoxib and substituted analogues have been reported which are nonsteroidal anti-inflammatory drugs for their cyclooxygenase (COX) inhibition, anti-inflammatory activity and ulcerogenic liability. In order to intermediate work-up, a continuous one-pot synthesis has been developed, performing the entire reaction sequence that results in a shorter time with good yield.


2019 ◽  
Vol 38 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Run Zhao ◽  
Yu-Juan Zhou ◽  
Ke-Cheng Jie ◽  
Jie Yang ◽  
Sébastien Perrier ◽  
...  

2017 ◽  
Vol 8 (4) ◽  
pp. 682-688 ◽  
Author(s):  
Sai Wang ◽  
Chenhao Yao ◽  
Mengfei Ni ◽  
Zuqiang Xu ◽  
Ming Cheng ◽  
...  

Thermo- and oxidation-responsive pillar[6]arene-ferrocene based supramolecular vesicles were constructed for controlled drug release.


Author(s):  
Ashfaq Adnan ◽  
Wing Kam Liu

While cancers have no known cure, some of them can be successfully treated with the combination of surgery and systematic therapy. In general, systemic/widespread chemotherapy is usually injected into the bloodstream to attempt to target cancer cells. Such procedure often imparts devastating side effects because cancer drugs are nonspecific in activity, and transporting them throughout the bloodstream further reduces their ability to target the right region. This means that they kill both healthy and unhealthy cells. It has been observed that the physiological conditions of the fluids around living cells can be characterized by pH, and the magnitude of pH around a living cell is different from cancerous cells. Moreover, a multiscale anatomy of carcinoma will reveal that the microstructure of cancer cells contains some characteristic elements such as specific biomarker receptors and DNA molecules that exclusively differentiate them from healthy cells. If these cancer specific ligands can be intercalated by some functional molecules supplied from an implantable patch, then the patch can be envisioned to serve as a complementary technology with current systemic therapy to enhance localized treatment efficiency, minimize excess injections/surgeries, and prevent tumor recurrence. The broader objective of our current research is to capture some fundamental insights of such drug delivery patch system. It is envisioned that the essential components of the device is nanodiamonds (ND), parylene buffer layer and doxorubicin (DOX) drugs. In its simplest form, self-assembled nanodiamonds - functionalized or pristine, and DOX molecules are contained inside parylene capsule. The efficient functioning of the device is characterized by its ability to precisely detect targets (cancer cells) and then to release drugs at a controlled manner. The fundamental science issues concerning the development of the ND-based device include: 1. A precise identification of the equilibrium structure and self assembled morphology of nanodiamonds, 2. Fundamental understanding of the drug adsorption and desorption process to and from NDs, and 3. The rate of drug release through the parylene buffers. The structure of the nanodiamond (ND) is crucial to the adsorption and desorption of drug molecules because it not only changes the self-assembly configuration but also alters the surface electrostatics. To date, the structure and electrostatics of NDs are not yet well understood. A density functional tight binding theory (DFTB) study on smaller [2] NDs suggests a facet dependent charge distributions on ND surfaces. These charges are estimated by Mulliken Analysis [1]. Using the charges for smaller NDs (∼valid for 1–3.3 nm dia ND) we first projected surface charges for larger (4–10 nm) truncated octahedral nanodiamonds (TOND), and it has been found that the [100] face and the [111] face contain positively and negatively charged atoms, respectively. These projected charges are then utilized to obtain the self assembled structure of pristine TONDs from Molecular Dynamics (MD) simulations [4] as shown in Fig. 1. The opposite charges on the [100] and [111] face invoked electrostatic attractions among the initially isolated NDs and a network of nanodiamond agglutinates are formed as evidenced in Fig. 1(b). This study confirms why as manufactured NDs are found in agglomerated form. The study also suggests that a large fraction of ND surfaces become unavailable for drug absorption as many of the [100] faces are coherently connected to [111] faces. As a result, it can be perceived that effective area for drug adsorption on ND surfaces will be less compared to theoretical prediction which suggests that a 4nm TOND may contain as high 360 drug molecules on its surface [5]. It has been observed that as manufactured NDs may contain a variety of functional groups, and currently, we are studying the mechanism of self-assembly for functionalized nanodiamonds so that we understand the role of functional groups. The next phase of calculation involves binding of the DOX to the NDs. Essentially, the understanding of drug absorption and desorption profile at a controlled rate to and from NDs is the most critical part of the device design. Some recent quantum calculation suggests that part of NDs and drug molecules contain opposite charges at their surfaces; it has been a natural interpretation that interactions between ND and drug molecules should be straight-forward — NDs should attract to drugs as soon as they come closure. Recent experiments [6], however, suggest that NDs usually do not interact with drug molecules in the presence of neutral solutions. Addition of NaCl in the solution improves the interaction dramatically. In the first part of the study, we [3–5] have studied the interaction of single DOX molecules with TOND surfaces via MD simulation. As shown in Fig. 2, this study suggests that DOX molecules first arrange them around the preferential sites on nanodiamonds (e.g. around the [111] face) and then spontaneously attach on the surface. It is also observed that only DOX molecule is attached per facets of TONDs. It can be noted that each TOND has 6 [100] face and 8 [111] faces. Figure 3 shows the energy minimization process during the DOX-ND interaction. It can be noted that these simulations have been performed in vacuum environment. In order to see how DOX interacts in solution media, another set of simulations have been conducted where “vacuum” environment have been replaced with solution media of different pH. Moreover, functionalization on the ND surfaces will create a different environment for the DOX molecules. Research is underway to capture the fundamental physics on the DOX loading and release to and from functionalized nanodiamonds. Once we understand the essential physics of drug loading and unloading, in the future we plan to model diffusion controlled drug release through ND coated film device by incorporating the multiscale science learned from the current study. Results from this study will provide fundamental insight on the definitive targeting of infected cells and high resolution controlling of drug molecules.


Author(s):  
Wing Kam Liu ◽  
Ashfaq Adnan

It has been demonstrated from recent research that nanodiamond(ND)-enabled drug delivery as cancer therapeutics represents an important component of optimized device functionality. The goal of the current research is to develop a multiscale modeling technique to understand the fundamental mechanism of a ND-based cancer therapeutic drug delivery system. The major components of the proposed device include nanodiamonds (ND), parylene buffer layer and doxorubicin (DOX) drugs, where DOX loaded self-assembled nanodiamonds are packed inside parylene capsule. The efficient functioning of the device is characterized by its ability to precisely detect targets (cancer cells) and then to release drugs at a controlled manner. The fundamental science issues concerning the development of the ND-based device includes (a) a precise identification of the equilibrium structure, surface electrostatics and self assembled morphology of nanodiamonds, (b) understanding of the drug/biomarker adsorption and desorption process to and from NDs, (c) rate of drug release through the parylene buffers, and finally, (d) device performance under physiological condition. In this study, we aim to systematically address these issues using a multscale computational framework. Specifically, the structure and electrostatics of the functionalized NDs are predicted by quantum scale calculation (Density Functional Tight Binding). The DFTB) study on smaller NDs suggests a facet dependent charge distributions on ND surfaces. Using the charges for smaller NDs (∼ valid for 1–3.3 nm dia ND), we then determined surface charges for larger (4–10 nm) truncated octahedral nanodiamonds (TOND). We found that the [100] face and the [111] face contain positively and negatively charged atoms, respectively. Employing this surface electrostatics of nanodiamonds, atomistic-scale simulations are performed to simulate the self-assembly process of the NDs and drug molecules in a solution as well as to evaluate nanoscale diffusion coefficient of DOX molecules. In order to quantify the nature of the aggregate morphology, a fractal analysis has been performed. The mass fractal dimensions for a variety of aggregate size have been obtained from molecular simulations assuming ‘diffusion-limited aggregation (DLA)’ process. Then, by considering the experimentally observed aggregate dimensions, by using DLA based fractal analysis and by utilizing Lagvankar-Gemmell Model for aggregate density, a continuum model for larger aggregates will be developed to characterize aggregate strengths and break-up mechanism, which in turn will help us to understand how aggregate size can be reduced. In this talk, an outline for this continuum model will be discussed. In addition, we have been performing molecular simulations on DOX-ND where multiple drug molecules are allowed to interact with a cluster of self-assembled nanodiamonds in pH controlled solution. The purpose of this study is to find the effect of solution pH on the loading and release of drug to and from nanodiamonds. Our initial results show that a higher pH is necessary to ensure drug release from nanodiamonds. Once we completely understand the essential physics of pH controlled drug loading and release, we plan to develop multiscale models of tumor nodules to represent them as a collection of individual tumor cells. Each cell will be then modeled as a deformable body comprised of three homogenous materials: cortex membrane, cytosol and nucleus. The cortex membrane and the cytosol will serve as a weak permeable medium where the absorption coefficients of the doxorubicin remain constant and obey Fick’s law. In this study, it will be assumed that drug release from the microdevice to its outer periphery will be governed by Fickian Diffusion. It will also be assumed that the complex flow of drug through the interstitial fluid of the body will be dictated by Darcy’s law. It will be assumed that the solute drug transport in these regions will be due to a combination of convection, diffusion, elimination in the intra- and extra-cellular space, receptive cell internalization and degradation. Results from this study will provide fundamental insight on the definitive targeting of infected cells and high resolution controlling of drug molecules.


2021 ◽  
Vol 407 ◽  
pp. 126667 ◽  
Author(s):  
Murat Kaya ◽  
Ismail Bilican ◽  
Muhammad Mujtaba ◽  
Idris Sargin ◽  
Merve Erginer Haskoylu ◽  
...  

2013 ◽  
Vol 31 (5) ◽  
pp. 1254-1263 ◽  
Author(s):  
Matthew Dickerson ◽  
Nickolas Winquist ◽  
Younsoo Bae

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