scholarly journals Aptamers Chemistry: Chemical Modifications and Conjugation Strategies

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 3 ◽  
Author(s):  
Fadwa Odeh ◽  
Hamdi Nsairat ◽  
Walhan Alshaer ◽  
Mohammad A. Ismail ◽  
Ezaldeen Esawi ◽  
...  

Soon after they were first described in 1990, aptamers were largely recognized as a new class of biological ligands that can rival antibodies in various analytical, diagnostic, and therapeutic applications. Aptamers are short single-stranded RNA or DNA oligonucleotides capable of folding into complex 3D structures, enabling them to bind to a large variety of targets ranging from small ions to an entire organism. Their high binding specificity and affinity make them comparable to antibodies, but they are superior regarding a longer shelf life, simple production and chemical modification, in addition to low toxicity and immunogenicity. In the past three decades, aptamers have been used in a plethora of therapeutics and drug delivery systems that involve innovative delivery mechanisms and carrying various types of drug cargos. However, the successful translation of aptamer research from bench to bedside has been challenged by several limitations that slow down the realization of promising aptamer applications as therapeutics at the clinical level. The main limitations include the susceptibility to degradation by nucleases, fast renal clearance, low thermal stability, and the limited functional group diversity. The solution to overcome such limitations lies in the chemistry of aptamers. The current review will focus on the recent arts of aptamer chemistry that have been evolved to refine the pharmacological properties of aptamers. Moreover, this review will analyze the advantages and disadvantages of such chemical modifications and how they impact the pharmacological properties of aptamers. Finally, this review will summarize the conjugation strategies of aptamers to nanocarriers for developing targeted drug delivery systems.

NANO ◽  
2015 ◽  
Vol 10 (05) ◽  
pp. 1530004 ◽  
Author(s):  
Ru Fang ◽  
Shaozong Yang ◽  
Yanbin Wang ◽  
Hua Qian

Paclitaxel (PTX) is usual for the treatment of a variety of malignancies, however, its applications are greatly limited due to its poor water solubility. Over the past years, there has been a considerable research interest in the area of nanoscale drug delivery systems (DDSs) as carrier for PTX due to their solubilization, safety, targeting and controlled release. There are many different types and shapes of nanoscale DDSs that have been prepared to deliver PTX, including nanoliposome, lipid nanoemulsion, nanosuspension, nanocapsule, nanofiber, nanotube, nanopolymersome, micelle and nanoparticle (NP). Nanoscale DDSs can be based on lipids, proteins, polysaccharides, polymers or other materials. The recent strategic developments of PTX formulation have been discussed with emphasis on lipid-, polymer- and protein-based nanoscale DDSs. Here we focus on the comparative analysis of the preparation, morphology, solubilization, targeting, penetrability, controllability and efficacy profile of various PTX-loaded nanoscale DDSs, which were reported in the different researches. Meanwhile the advantages and disadvantages are also discussed for each type of DDS. Furthermore, the current review embodies an in-depth discussion of human serum albumin (HSA) NP formulation, which showed significantly great efficacy and low toxicity. All the information obtained in this review might shed light on designing new and better nanoscale PTX formulations for potential anticancer applications in the clinic.


2017 ◽  
Vol 6 (7) ◽  
pp. 5426 ◽  
Author(s):  
Hiren J. Patel ◽  
Vaishnavi P. Parikh

The pharmaceutical industry has faced several marked challenges in order to bring new chemical entities (NCEs) into the market over the past few decades. Various novel drug delivery approaches have been used as a part of life cycle management from which Osmotic drug delivery systems look the most promising one. After discussing the history of osmotic pump development, this article looks at the principles, advantages and disadvantages of osmotic drug delivery systems. Then, the basic components of osmotic pump and factors affecting the design of oral osmotic drug delivery systems are discussed in detail. In the later part of the manuscript, various types of osmotic pumps available in the market and evaluation methods for osmotic drug delivery systems are discussed in detail.


2021 ◽  
Vol 184 ◽  
pp. 218-234
Author(s):  
Paulo Vitor França Lemos ◽  
Henrique Rodrigues Marcelino ◽  
Lucas Guimarães Cardoso ◽  
Carolina Oliveira de Souza ◽  
Janice Izabel Druzian

Author(s):  
И.Ю. Малышев ◽  
Л.В. Кузнецова ◽  
О.П. Буданова

В обзоре представлены современные данные о механизмах диагностики, планирования и оценки успешности терапии различных заболеваний с помощью экзосом, об использовании их как нанопереносчиков (т.е. нановезикул для эффективной доставки молекул). За последние годы разработано большое количество разных, в основном синтетических, систем доставки лекарственных средств, недостатками этих систем является плохая биосовместимость и органическая неспособность к высокоточной доставке загруженных веществ. По сравнению с синтетическими системами доставки лекарственных средств, экзосомы - вследствие своего естественного происхождения - могут обладать большими преимуществами, такими, как лучшая биосовместимость и повышенная устойчивость к разрушительному воздействию иммунной системы. Описана технология производства наноструктур, разработка и производство с помощью бионанотехнологий так называемых «полностью синтетических экзосомоподобных нановезикул», преимущества и недостатки этих методов. This review presents current data on mechanisms for diagnosis, planning, and evaluation of success in the treatment of various diseases using exosomes as nanocarriers (i.e., nanovesicles for efficient delivery of molecules). In recent years, a large number of different, mainly synthetic drug delivery systems has been developed. Disadvantages of these systems are poor biocompatibility and organic inability to deliver high-precision loaded substances. Compared with synthetic drug delivery systems, exosomes due to their natural origin may provide great advantages, such as better biocompatibility and increased resistance to detrimental effects of the immune system. This review describes in detail a technology of nanostructure production, the development and production of so-called fully synthetic exosome-like nanovesicles using bionanotechnology, and advantages and disadvantages of these methods.


Molecules ◽  
2019 ◽  
Vol 24 (14) ◽  
pp. 2570 ◽  
Author(s):  
Inés Serrano-Sevilla ◽  
Álvaro Artiga ◽  
Scott G. Mitchell ◽  
Laura De Matteis ◽  
Jesús M. de la Fuente

Natural polysaccharides are frequently used in the design of drug delivery systems due to their biocompatibility, biodegradability, and low toxicity. Moreover, they are diverse in structure, size, and charge, and their chemical functional groups can be easily modified to match the needs of the final application and mode of administration. This review focuses on polysaccharidic nanocarriers based on chitosan and hyaluronic acid for small interfering RNA (siRNA) delivery, which are highly positively and negatively charged, respectively. The key properties, strengths, and drawbacks of each polysaccharide are discussed. In addition, their use as efficient nanodelivery systems for gene silencing applications is put into context using the most recent examples from the literature. The latest advances in this field illustrate effectively how chitosan and hyaluronic acid can be modified or associated with other molecules in order to overcome their limitations to produce optimized siRNA delivery systems with promising in vitro and in vivo results.


2020 ◽  
Vol 175 ◽  
pp. 07002
Author(s):  
Elena Kastarnova ◽  
Vladimir Orobets ◽  
Valeria Shahova ◽  
Olga Sevostyanova ◽  
Ilya Belyaev ◽  
...  

One of the main promising directions in the development of pharmacology is the development of drugs that provide targeted drug concentration and effective approaches to obtaining them using nanoscale drug delivery systems. In our opinion, the most promising is the use of biodegradable delivery systems due to their low toxicity and xenobiotic effects on the patient’s body. The need to develop regulated drug delivery systems is due to their clear advantage over analogues in standardized dosage forms. Based on modern research publications we have developed an exosomal antibacterial form of azithromycin that has pronounced selective properties for respiratory epithelial cells. The aim of the work was to study the safety parameters of the developed drug based on exosomal particles, in particular subchronic toxicity. For the study 3 experimental and 1 control groups of white rats weighing 190-220 g were formed with 10 heads each. The drug was administered intragastrically daily for 90 days in doses of 1/10; 1/20 and 1/50 of the LD50 set in the acute experiment. The study found that the use of the developed exosomal drug intragastrically once a day for 90 days does not affect the behavioral responses of animals and their external condition.


2018 ◽  
Vol 10 (2) ◽  
pp. 1 ◽  
Author(s):  
Revathy B. Menon ◽  
Lakshmi V. S. ◽  
Aiswarya M. U. ◽  
Keerthana Raju ◽  
Sreeja C. Nair

A novel drug delivery system is the one that ensures optimum dose at the right time, at the right location. Porphysomes are among those drug delivery systems. Porphysomes are a means of vesicular drug delivery systems. They are liposome-like structures composed completely of porphyrin lipid. The porphysomes encapsulates the active medicament in vesicular structure. They are having an aqueous core which can be loaded with the medicament. They have the capacity to destroy the disease tissues. They absorb the heat in the near infrared region and release this heat to destroy the diseased tissues. Porphysomes are having immense applications in the field of positron-electron therapy (PET), photoacoustic imaging, photothermal therapy etc. This review article discusses regarding the Porphysome-the drug delivery system, its advantages and disadvantages, composition, method of preparation, applications and various aspects related to the porphysomal drug delivery.


2021 ◽  
Vol 14 (10) ◽  
pp. 946
Author(s):  
Bianca Enaru ◽  
Sonia Socaci ◽  
Anca Farcas ◽  
Carmen Socaciu ◽  
Corina Danciu ◽  
...  

Liposome-based delivery systems have been studied and used more frequently in recent years due to their advantages, such as low toxicity, specificity, and the ability to protect the encapsulated substance from environmental factors, which could otherwise degrade the active compound and reduce its effectiveness. Given these benefits, many researchers have encapsulated polyphenols in liposomes, thus increasing their bioavailability and stability. Similarly, polyphenols encapsulated in liposomes are known to produce more substantial effects on targeted cells than unencapsulated polyphenols, while having minimal cytotoxicity in healthy cells. Although polyphenols play a role in preventing many types of disease and generally have beneficial effects on health, we solely focused on their chemopreventive effects on cancer through liposomes in this review. Our goal was to summarize the applicability and efficacy of liposomes encapsulated with different classes of polyphenols on several types of cancer, thus opening the opportunity for future studies based on these drug delivery systems.


Author(s):  
Srikanth Reddy Sokkula ◽  
Suresh Gande

Lipid-based drug delivery systems are extensively reported in literature for enhancing the drug solubility, permeability and bioavailability. These systems include   simple oil solutions, coarse, multiple and dry emulsions, complex self-emulsifying, microemulsifying or nanoemulsifying drug delivery systems. Self-emulsifying systems are further classified as self-microemulsifying drug delivery systems (SMEDDS) and self-nanoemulsifying drug delivery systems (SNEDDS) are most prevailing and commercially viable oil based approach for drugs that exhibit low dissolution rate and inadequate absorption. Ever since the progress of SNEDDS, they drew the interest of researchers in order to deal with the challenges of poorly water-soluble drugs. SNEDDS is a proven method for enhancing solubility and bioavailability of lipophilic compounds. Considering the ease of large-scale production and the robustness of SNEDDS, several formulations techniques are commercially available. The stability of SNEDDS can be further enhanced by solidifying liquid SNEDDS. Controlled release and supersaturated SNEDDS received patient compliance with larger drug loading. Presence of biodegradable ingredients and ‘drug-targeting opportunities’ facilitate SNEDDS a clear merit and distinction amongst available solubility enhancement techniques. In this article attempt was made to present an overview of SNEDDS, their mechanism, formulation excipients and potentials of SNEDDS, recent advancements, advantages and disadvantages of SNEDDS formulations. The article also focuses on reviewing the application of SNEDDS in enhancing bioavailability of antihypertensive drugs.


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