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Marine Polysaccharides in Pharmaceutical Applications
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Riyasree Paul, Sourav Kabiraj, Sreejan Manna, Sougata Jana
Chawla et al. have investigated the efficacy of alginate-based mucoadhesive microbeads for delivering naproxen sodium. Emulsification method was employed to synthesize calcium chloride cross-linked alginate microbeads. Eudragit S-100 was used to coat the developed microbeads. The core microbeads showed an enhanced mucoadhesive property in respect to coated microbeads. The uncoated microspheres exhibited pH-dependent sustained drug release following Higuchi kinetics, where s the coated microspheres demonstrated Korsmeyer-Peppas kinetics (Chawla et al. 2012). Alginate-gellan gum based microspheres were synthesized for oral delivery of aceclofenac by Jana et al. The average size of the microparticles was reported between 270 and 490 μm. An in vitro drug release study revealed a sustained release of aceclofenac over 6 hours following Korsemeyer-Peppas kinetics. An in vivo study performed on a rabbit model revealed sustained absorption of drug with an excellent anti-inflammatory effect (Jana et al. 2013). Another study conducted by Jana et al. reported the development of alginate and locust bean gum based interpenetrating polymeric network (IPN) microspheres for oral delivery of aceclofenac. The ionic gelation technique was employed to develop calcium ion cross-linked microspheres. An in vitro study revealed sustained release of aceclofenac over 8 hours in pH 6.8 phosphate buffer. An increased polymer concentration has decreased the aceclofenac release percentage, as shown in Figure 5.3. Pharmacodynamic analysis exhibited a sustained anti-inflammatory effect after oral administration (Jana et al. 2015).
Application of Bioresponsive Polymers in Drug Delivery
Published in Deepa H. Patel, Bioresponsive Polymers, 2020
Manisha Lalan, Deepti Jani, Pratiksha Trivedi, Deepa H. Patel
Another example of thermosensitive ‘Smart polymer’ for controlled release of heparin is alginate-hydroxy propyl cellulose-based microbeads for which the release profiles were studied at different temperatures and various alginate/hydroxypropyl cellulose compositions. Such microbeads are spherical in shape with 3 micron diameter and contain encapsulated heparin obtained through emulsification method. The internal structure, surface structure, and morphology of microbeads were estimated by fluorescence microscopy, scanning electron microscopy and atomic force microscopy respectively. Lower critical solution temperature (LCST) of the systems was measured and release profile of heparin complex method showed three-stage sustained release for at least 16 days at 37°C. The release was correlated with size of pores present on surface of micro-beads and can be controlled by temperature and composition of Alginate/Hydroxy Propyl Cellulose microbeads [142].
Tissue is the Issue
Published in Brian Leyland-Jones, Pharmacogenetics of Breast Cancer, 2020
Magnetic labeling (~45 min) Centrifuge sample for 10 minutes at 300g at room temperature.Carefully remove the supernatant completely.Resuspend cell pellet in appropriate amount of buffer as specified by the microbeads package insert. For fewer cells, use the same volume.Add microbeads per package insert.Incubate for 15 minutes at 6°C to 12°C. For less than 5 x 106 total cells, use the same volume.Wash cells by adding 10 to 20 times the labeling volume of buffer and centrifuge at 300g for 10 minutes.Remove supernatant completely (save the supernatant in appropriately labeled 1 mL cryovial) and resuspend cell pellet in appropriate amount of buffer (1 mL of buffer/108 total cells).Proceed to magnetic separation.
ROS-generating, pH-responsive and highly tunable reduced graphene oxide-embedded microbeads showing intrinsic anticancer properties and multi-drug co-delivery capacity for combination cancer therapy
Published in Drug Delivery, 2022
Adilakshmi Boddu, Obireddy Sreekanth Reddy, Dahong Zhang, K. S. V. Krishna Rao, Wing-Fu Lai
To prepare chitosan microbeads, 200 mg of CS was transferred into 10 mL of distilled water containing 1% acetic acid and stirred overnight to get a homogenous solution. 100 mg of 5-FU and 50 mg of rGO were added under stirring up to form a homogeneous solution. Then the mixture was transferred into a 10% w/v STPP solution. The microbeads (CS-rGO-5FU) formed were collected and washed several times with water before being air-dried at ambient conditions. Similarly, SA-5-FU microbeads were synthesized by the above procedure without the addition of rGO. SA microspheres-loaded microbeads (CS-rGO-5FU-SA-CUR) were synthesized by using a similar procedure. During the preparation process, after forming a homogeneous solution containing 5-FU and rGO, the microspheres were added and transferred dropwise into 100 mL of 5% calcium chloride solution to form microbeads. The formed microbeads were collected, filtered, and treated with distilled water. The microbeads were then dried at room temperature and put into airtight containers until they were ready to be used again. Similarly, CS-5FU-SA-CUR microbeads were synthesized by the above procedure without the addition of rGO. The preparation of multi-drug-based delivery system is presented schematically in Scheme 1.
Implantable drug delivery systems for the treatment of osteomyelitis
Published in Drug Development and Industrial Pharmacy, 2022
Megan Smith, Matthew Roberts, Raida Al-Kassas
There is always potential for improvement in regard to hydrogels through improving their osteoconductivity, biocompatibility, osteoinductivity and osteogenesis capabilities. The three most explored hydrogel structures are hydrogel microbeads, nanogels and hydrogel fibers. Microbeads can be formulated through many techniques including emulsification and have many benefits over conventional hydrogels. They have an increased surface area which facilitates and enhances the mass transfer of stem cells to bone defect sites. Hydrogel nanoparticles (nanogels) are chemically or physically cross-linked polymers that can swell in water. They are ideal for drug delivery due to their tunable size, uniformity and their ease in design and formulation. Hydrogel fibers are a fibrous structure fabricated through a two-step process of spinning and crosslinking. They can be injected directly into the defect site and remain at the defect site for an extended period over hydrogels and microbeads. They have a large surface area to volume ratio making them a potential candidate for bone tissue engineering. However, hydrogel fibers have some major drawbacks in comparison to other structures, they have poor mechanical strength so unable to bear load and a high swelling ratio [111].
The first evidence of microplastic uptake in natural freshwater mussel, Unio stevenianus from Karasu River, Turkey
Published in Biomarkers, 2022
Irregularly shaped microplastics were the most predominant in this study and spherical shaped microplastics, especially microbeads, were also observed at low concentrations in mussels. But, Li et al. (2015) observed a high concentration of spherical microplastics in oysters. The microbeads are commonly used in facial cleansers and other consumer products (e.g. sandblasting media, abrasives) (Eriksen et al. 2013). Additionally, Saruhan et al. (2010) reported that sewage sludge, which may contain microbeads, is generally used as fertilizer in agriculture and public lands. There is an intense agricultural activity around the Karasu River and due to the fertilization carried out in these areas, microbeads may be carried to the river by surface flows. Hence, there are multiple point sources such as wastewaters and agricultural activities where microbeads may enter the Karasu River.