scholarly journals MODIFICATION OF GUMS BY PERIODATE OXIDATION: A NATURAL CROSS-LINKER

Author(s):  
Suma Oommen Sen ◽  
Amit Kumar Nayak ◽  
Pritesh Devbhuti ◽  
Amitava Ghosh

Scientists throughout the world are in search of novel modified biopolymer to fabricate smart drug delivery systems based on hydrogel formulations using several cross-linkers like glutaraldehyde, glyoxal, epichlorhydrin, adipic acid dihydrazide, carbodiimide, genipin, etc. Agents that are fused into the polymeric structure like isocyanates, glutaraldehyde, polyepoxides, etc., and are extremely toxic in nature. In addition, these are susceptible to percolate out into the body on biodegradation of polymeric structure. As an alternative to these toxic cross-linking agents, the periodate-Schiff base staining technique is widely being used for cross-linking in biology and biochemistry. The mechanism of this cross-linking technique is based on the reaction in-between the Schiff reagent and the aldehydes produced via the periodate oxidation. During the past few decades, several researchers have already been studied on the natural gums and also, developed their dialdehyde derivatives via the periodate oxidation technique. These periodate oxidized gums are being used to cross-link gelatin, other proteins and chitosan to develop various smart systems for drug delivery, tissue engineering, wound dressing, edible films, etc. The current review presents a comprehensive discussion of the available reported literature on the periodate oxidation of various gums and their use as natural cross-linker.

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1989 ◽  
Author(s):  
Natalia Sedyakina ◽  
Andrey Kuskov ◽  
Kelly Velonia ◽  
Nataliya Feldman ◽  
Sergey Lutsenko ◽  
...  

Microparticles, aimed for oral protein and peptide drug delivery, were prepared via emulsion cross-linking using citric acid as cross-linker and polyglycerol polyricinoleate as surfactant. A comparative study of the interaction between chitosan and citric acid and its effect on the resulting microparticle properties was performed using different chitosan-to-cross-linker mass ratios and pH-values during fabrication of the microparticles. Non-cross-linked and cross-linked microparticles were studied in terms of size (4–12 μm), zeta potential (−15.7 to 12.8 mV), erosion (39.7–75.6%), a model protein encapsulation efficiency (bovine serum albumin) (6.8–27.6%), and loading capacity (10.4–40%). Fourier transform infrared spectroscopy and X-ray diffraction confirmed the ionic interaction between the protonated amine groups of chitosan and the carboxylate ions of the cross-linking agent. Scanning electron microscopy revealed that the non-cross-linked microparticles had an uneven shape with wrinkled surfaces, while the cross-linked formulations were spherical in shape with smooth surfaces. On the basis of these data, the role of the surfactant and microparticle structure on the release mechanism was proposed. Control of the microparticle shape and release mechanisms is expected to be crucial in developing carriers for the controlled delivery of proteins and peptides.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 680
Author(s):  
Sara Perteghella ◽  
Giovanna Rassu ◽  
Elisabetta Gavini ◽  
Antonella Obinu ◽  
Elia Bari ◽  
...  

The nose-to-brain delivery route is used to bypass the blood–brain barrier and deliver drugs directly into the brain. Over the years, significant signs of progress have been made in developing nano-drug delivery systems to address the very low drug transfer levels seen with conventional formulations (e.g., nasal solutions). In this paper, sericin nanoparticles were prepared using crocetin as a new bioactive natural cross-linker (NPc) and compared to sericin nanoparticles prepared with glutaraldehyde (NPg). The mean diameter of NPc and NPg was about 248 and 225 nm, respectively, and suitable for nose-to-brain delivery. The morphological investigation revealed that NPc are spherical-like particles with a smooth surface, whereas NPg seem small and rough. NPc remained stable at 4 °C for 28 days, and when freeze-dried with 0.1% w/v of trehalose, the aggregation was prevented. The use of crocetin as a natural cross-linker significantly improved the in vitro ROS-scavenging ability of NPc with respect to NPg. Both formulations were cytocompatible at all the concentrations tested on human fibroblasts and Caco-2 cells and protected them against oxidative stress damage. In detail, for NPc, the concentration of 400 µg/mL resulted in the most promising to maintain the cell metabolic activity of fibroblasts higher than 90%. Overall, the results reported in this paper support the employment of NPc as a nose-to-brain drug delivery system, as the brain targeting of antioxidants is a potential tool for the therapy of neurological diseases.


1990 ◽  
Vol 267 (3) ◽  
pp. 585-591 ◽  
Author(s):  
U Heimgartner ◽  
B Kozulić ◽  
K Mosbach

After periodate oxidation and incubation with a dihydrazide, cross-linking of the two heavy chains of immunoglobulins G from several species proceeds specifically through their oligosaccharides. We have used malonic acid dihydrazide, adipic acid dihydrazide and dithiodipropionic acid dihydrazide. The last compound is introduced in this work as a cleavable-carbohydrate-specific cross-linker. It was found that in rabbit and human immunoglobulins the degree of cross-linking was strongly dependent on the oxidation conditions but only very weakly dependent on the concentration and size of the dihydrazides. Papain cleavage of the cross-linked rabbit IgG indicated that the cross-linking occurred predominantly, if not exclusively, in the Fc region, probably through the two glycans linked to Asn-297 in the CH2 domain of each of the two heavy chains. The immunoglobulins from sheep, pig, goat and guinea pig show a comparable cross-linking pattern, indicating that the sugar chains from these immunoglobulins have a spatial structure closely related to that of rabbit and human IgG. When dithiodipropionic acid dihydrazide was used as the cross-linker, the cross-link could be cleaved by mercaptoethanol.


Author(s):  
S.K. Aggarwal ◽  
J.M. Fadool

Cisplatin (CDDP) a potent antitumor agent suffers from severe toxic side effects with nephrotoxicity being the major dose-limiting factor, The primary mechanism of its action has been proposed to be through its cross-linking DNA strands. It has also been shown to inactivate various transport enzymes and induce hypocalcemia and hypomagnesemia that may be the underlying cause for some of its toxicities. The present is an effort to study its influence on the parathyroid gland for any hormonal changes that control calcium levels in the body.Male Swiss Wistar rats (Crl: (WI) BR) weighing 200-300 g and of 60 days in age were injected (ip) with cisplatin (7mg/kg in normal saline). The controls received saline injections only. The animals were injected (iv) with calcium (0.5 ml of 10% calcium gluconate/day) and were killed by decapitation on day 1 through 5. Trunk blood was collected in heparinized tubes.


2020 ◽  
Vol 10 (2) ◽  
pp. 53-59
Author(s):  
Bharathi M ◽  
Mullaikodi O ◽  
Rajalingam D ◽  
Gnanasekar N ◽  
Kesavan M

A Microsponge (MS) is an extremely interconnected, permeable, polymeric structure that involves permeable microparticles trapping and discharging through the skin for a considerable time period. Drug delivery system (DDS) offer extended discharge with less degradation, improved physical stability along with better tolerance. The main intend of any DDS is to achieve the required amount of drug in plasma to produce the desired therapeutic and non-poisonous effect over a prolonged period of time. Specific methods for preparing MS were reviewed in this current investigation, and their pharmaceutical implementations were signed. MS have major DDS point of interest. It also improves stability, increased flexibility in formulation and increased elegance. In fact, numerous studies have reported that MS supplies are not allergic, mutagenic, and poisonous. MS creativity is used in products such as sunscreen, prescription, cosmetics, and OTC skin care. This inquiry primarily focuses on the different methods used to identify, plan and exploit MS.


Author(s):  
Vikas V. Gaikwad ◽  
Abasaheb B. Patil ◽  
Madhuri V. Gaikwad

Scaffolds are used for drug delivery in tissue engineering as this system is a highly porous structure to allow tissue growth.  Although several tissues in the body can regenerate, other tissue such as heart muscles and nerves lack regeneration in adults. However, these can be regenerated by supplying the cells generated using tissue engineering from outside. For instance, in many heart diseases, there is need for heart valve transplantation and unfortunately, within 10 years of initial valve replacement, 50–60% of patients will experience prosthesis associated problems requiring reoperation. This could be avoided by transplantation of heart muscle cells that can regenerate. Delivery of these cells to the respective tissues is not an easy task and this could be done with the help of scaffolds. In situ gel forming scaffolds can also be used for the bone and cartilage regeneration. They can be injected anywhere and can take the shape of a tissue defect, avoiding the need for patient specific scaffold prefabrication and they also have other advantages. Scaffolds are prepared by biodegradable material that result in minimal immune and inflammatory response. Some of the very important issues regarding scaffolds as drug delivery systems is reviewed in this article.


2018 ◽  
Vol 68 (12) ◽  
pp. 2925-2918
Author(s):  
Gabriela Cioca ◽  
Maricel Agop ◽  
Marcel Popa ◽  
Simona Bungau ◽  
Irina Butuc

One of the main challenges in designing a release system is the possibility to control the release rate in order to maintain it at a constant value below a defined limit, to avoid exceeding the toxicity threshold. We propose a method of overcoming this difficulty by introducing the drug into liposomes, prior to its inclusion in the hydrogel. Furthermore, a natural cross linker (as is tannic acid) is used, instead of the toxic cross linkers commonly used, thus reducing the toxicity of the release system as a whole.


2018 ◽  
Vol 69 (7) ◽  
pp. 1756-1759 ◽  
Author(s):  
Luminita Confederat ◽  
Iuliana Motrescu ◽  
Sandra Constantin ◽  
Florentina Lupascu ◽  
Lenuta Profire

The aim of this study was to optimize the method used for obtaining microparticles based on chitosan � a biocompatible, biodegradable, and nontoxic polymer, and to characterize the developed systems. Chitosan microparticles, as drug delivery systems were obtained by inotropic gelation method using pentasodiumtripolyphosphate (TPP) as cross-linking agent. Chitosan with low molecular weight (CSLMW) in concentration which ranged between 0.5 and 5 %, was used while the concentration of cross-linking agent ranged between 1 and 5%. The characterization of the microparticles in terms of shape, uniformity and adhesion was performed in solution and dried state. The size of the microparticles and the degree of swelling were also determined. The structure and the morphology of the developed polymeric systems were analyzed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM).The average diameter of the chitosan microparticles was around 522 �m. The most stable microparticles were obtained using CSLMW 1% and TPP 2% or CSLMW 0.75%and TPP 1%. The micropaticles were spherical, uniform and without flattening. Using CSLMW in concentration of 0.5 % poorly cross-linked and crushed microparticles have been obtained at all TPP concentrations. By optimization of the method, stable chitosan-based micropaticles were obtained which will be used to develop controlled release systems for drug delivery.


2019 ◽  
Vol 25 (34) ◽  
pp. 3608-3619 ◽  
Author(s):  
Uzma Arif ◽  
Sajjad Haider ◽  
Adnan Haider ◽  
Naeem Khan ◽  
Abdulaziz A. Alghyamah ◽  
...  

Background: Biocompatible polymers are gaining great interest in the field of biomedical applications. The term biocompatibility refers to the suitability of a polymer to body and body fluids exposure. Biocompatible polymers are both synthetic (man-made) and natural and aid in the close vicinity of a living system or work in intimacy with living cells. These are used to gauge, treat, boost, or substitute any tissue, organ or function of the body. A biocompatible polymer improves body functions without altering its normal functioning and triggering allergies or other side effects. It encompasses advances in tissue culture, tissue scaffolds, implantation, artificial grafts, wound fabrication, controlled drug delivery, bone filler material, etc. Objectives: This review provides an insight into the remarkable contribution made by some well-known biopolymers such as polylactic-co-glycolic acid, poly(ε-caprolactone) (PCL), polyLactic Acid, poly(3- hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), Chitosan and Cellulose in the therapeutic measure for many biomedical applications. Methods: : Various techniques and methods have made biopolymers more significant in the biomedical fields such as augmentation (replaced petroleum based polymers), film processing, injection modeling, blow molding techniques, controlled / implantable drug delivery devices, biological grafting, nano technology, tissue engineering etc. Results: The fore mentioned techniques and other advanced techniques have resulted in improved biocompatibility, nontoxicity, renewability, mild processing conditions, health condition, reduced immunological reactions and minimized side effects that would occur if synthetic polymers are used in a host cell. Conclusion: Biopolymers have brought effective and attainable targets in pharmaceutics and therapeutics. There are huge numbers of biopolymers reported in the literature that has been used effectively and extensively.


2019 ◽  
Vol 24 (44) ◽  
pp. 5296-5312 ◽  
Author(s):  
Fakhara Sabir ◽  
Rai K. Farooq ◽  
Asim.ur.Rehman ◽  
Naveed Ahmed

Monocytes are leading component of the mononuclear phagocytic system that play a key role in phagocytosis and removal of several kinds of microbes from the body. Monocytes are bone marrow precursor cells that stay in the blood for a few days and migrate towards tissues where they differentiate into macrophages. Monocytes can be used as a carrier for delivery of active agents into tissues, where other carriers have no significant access. Targeting monocytes is possible both through passive and active targeting, the former one is simply achieved by enhanced permeation and retention effect while the later one by attachment of ligands on the surface of the lipid-based particulate system. Monocytes have many receptors e.g., mannose, scavenger, integrins, cluster of differentiation 14 (CD14) and cluster of differentiation 36 (CD36). The ligands used against these receptors are peptides, lectins, antibodies, glycolipids, and glycoproteins. This review encloses extensive introduction of monocytes as a suitable carrier system for drug delivery, the design of lipid-based carrier system, possible ways for delivery of therapeutics to monocytes, and the role of monocytes in the treatment of life compromising diseases such as cancer, inflammation, stroke, etc.


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