Controlled Drug Delivery Systems Research Articles

Formulation and Evaluation of Solid Lipid Nanoparticles for controlled delivery of Zidovudine

Zidovudine is one of the chief nucleoside analogue and reverse inhibitor licensed for HIV infection which is placed along with a group of retroviruses. The present research study on Zidovudine solid dosage form surveyed the feasibility utilizing solid lipid nanoparticles (SLNs) for controlled drug delivery of zidovudine embracing glyceryl behenate as lipidic material, tween 80 as a stabilizer and blend of sodium chelate with poloxamer as surfactant. The SLNs were prepared utilizing high pressure homogenization followed by ultrasonication method. The prepared SLNs were characterized by particle size analysis, polydispersity index, zeta potential, DSC, TEM, IR spectroscopy, and X-ray diffractometry. Narrow size distribution of the particles was marked having polydispersity index values under 0.8. The high zeta potential of the different SLN formulations additionally showed their physical stability. Differential scanning calorimetry and powder X-ray diffraction showed decline in crystallinity of drug in the nanoparticle formulation. In vitro release study showed sustained release for up to 12 hours in the SLN formulations prepared. The current study results revealed that zidovudine SLN formulation prepared by high pressure homogenization followed by ultrasonication is a suitable method for controlled drug delivery system.

Encapsulation and Release of Doxorubicin from TiO2 Nanotubes: Experiment, Density Functional Theory Calculations, and Molecular Dynamics Simulation.

Titanium dioxide (TiO2) nanotubes are attractive materials for drug-delivery systems because of their biocompatibility, chemical stability, and simple preparation. In this study, we loaded TiO2 nanotubes with anticancer drug doxorubicin (DOX) experimentally and in all-atom molecular dynamics (MD) simulations. The release of doxorubicin from the nanotubes was studied by high-performance liquid chromatography (HPLC) and confocal Raman spectroscopy, and drug-release profiles were evaluated under various conditions. The polyethylene glycol (PEG) coating and capping of the nanotubes led to a marked increase in the water contact angles from about 16 to 33° in keeping with reduced wettability. The capping retarded the release rate without decreasing the overall release amount. The MD simulations further show that the DOX molecule diffusion coefficients (Di) are in the order of 10-10 m2/s. The DOX molecules show a plethora of short- and long-range H-bonding interactions with TiO2 nanotube walls and water. Calculated radial distribution functions (RDFs) and combined radial/angular distribution functions (CDFs) allowed gauging the strength of these hydrogen bonds. The strength does not fully correlate with the pKa values of DOX atoms which we assign to the confinement of DOX and water in the tubes. The lifetimes of hydrogen bonds between the DOX atoms and water molecules are shorter than that of the DOX...TiO2 interactions, and DOX...DOX aggregation does not play an important role. These results suggest TiO2 nanotubes as promising candidates for controllable drug-delivery systems for DOX or similar antiproliferative molecules.

The effect of the polyethylene glycol chain length of a lipopolymer (DSPE-PEGn) on the properties of DPPC monolayers and bilayers

Due to the growing importance of controlled drug delivery systems (DDS), the main task of nanotechnology is to develop stable, effective and non-toxic nanocarriers in which the drug can be encapsulated and delivered to a specific diseased site in the patient's body. Currently, one of the most popular ways to improve the pharmacokinetic and physicochemical properties of liposomes is introducing into their structure poly(ethylene glycol) chains conjugated with 1,2-disteroil-sn-glycero-3-phosphoethanolamine (DSPE) molecules. Because the research so far does not give an unequivocal answer which length of PEG chains is more beneficial for liposomes properties, the aim of this work was to investigate the influence of this parameter (DSPE-PEG350, DSPE-PEG750 and DSPE-PEG2000) on model DPPC membrane. The studies were performed on monolayer and bilayer systems and were related to the surface pressure measurements, Brewster angle microscopy experiments, Grazing Incidence X-ray Diffraction studies, dynamic light scattering and zeta potential measurements and the experiments with the calcein release and steady-state fluorescence anisotropy of DPH. The obtained results proved that the molecular organization of the DPPC membrane strongly depends on the length of poly(ethylene glycol) chains conjugated with DSPE. Moreover, the addition of different lengths of polymer chains changes the properties of formulated liposomes, especially their stability, permeability, size and surface charge.

Preparation and characterization of fluorometholone molecular imprinted soft contact lenses as ocular controlled drug delivery systems

The molecular imprinted (MIP) and non-imprinted (NIP) lenses were synthesized in presence and absence of Fluorometholone (FML) as the template molecule. Hydroxyethyl methacrylate (HEMA), as a backbone monomer, methacrylic acid (MAA) as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross-linker monomer were applied to preparing soft contact lenses with different FML: MAA molar ratios. The lenses were characterized by determination of swelling and binding properties in water. Transparency and differential scanning calorimetry (DSC) properties of Drug-loaded and drug-free MIP lenses were also studied. Their loading and release properties were also studied using Korsmeyer-Peppas equation in Normal Saline (0.9% NaCl) and Artificial Tears media. There was no significant difference in swelling percentage of MIP and NIP lenses (p-value>0.05). No endothermic peak was seen at the melting point of FML in thermograms of drug-free and drug-loaded MIP lenses. It was found that all MIP lenses had higher binding affinity to FML in comparison with NIP (p-value<0.05). According to drug release data, Korsmeyer-Peppas equation shows non-Fickian diffusion pattern from hydrogel in 0.9% Normal Saline and Artificial Tears media and MIP1:12 had superior binding and release properties. The results of the present work indicated that molecular imprinting technique had a significant effect on improving loading capacity and sustaining drug release from hydrogels. According to our data MIP1:12 had more FML loading capacity and superior controlled release properties compared to other polymers and can be evaluated, in future studies, for making FML imprinted soft contact lenses.

Preparation and Physical Properties of PCL-Metoprolol Tartrate Electrospun Nanofibers as Drug Delivery System

Electrospinning is considered a promising technology for encapsulating and loading various drugs into nanofibers. Metoprolol tartrate (MPT), hydrophilic therapy, was used as model drug. Metoprolol tartrate was loaded into poly(ɛ-caprolactone) (PCL) via blend and emulsion electospinning. The preparation processes, morphology, chemical structure thermal properties were evaluated. FESEM showed that emulsion electospinning produce larger fiber diameters(301.775nm) when compared to fibers produced by blend electrospinning(112.463, 249.34)nm, the PCL/ span 80 and MPT-PCL by emulsion method which have high fiber diameter than pure PCL and MPT-PCL by blend method and the Tm of pure PCL nanofibers and all drug loaded scaffolds are around 60°C from DSC test, water contact angle to pure PCL electrospun mats hydrophobic character (126.2°), while PCL/span 80, and PCL-drug nanofiber mats showed hydrophilic character. Our study demonstrated the possibility of using electrospinning with a promising good potential toward sustained and controlled drug delivery system.

Biocompatible thermo-responsive N-vinylcaprolactam based hydrogels for controlled drug delivery systems

The treatment of several diseases requires drugs commonly administered orally or intravenously. Said administration has several drawbacks, such as low control of the necessary drug levels in plasma, making the treatment ineffective and, furthermore, side effects and low compatibility with the patient. Recently, the use of stimuli-responsive hydrogels in controlled Drug Delivery Systems (DDSs) has been considered an excellent alternative because of its inherent biocompatibility, responsiveness to physiological changes in the body, and diversity of both natural and synthetic material options. The present work focuses mainly on the synthesis, characterization, and drug release capacity of poly (N-vinyl caprolactam) (PVCL) and poly (N-vinyl caprolactam) microgels crosslinked with various concentrations of poly (ethylene glycol) diacrylate (PEGDA), which show temperature stimuli-responsiveness near the physiological temperature of the human body. For that reason, changes in the average hydrodynamic particle diameter at different temperatures are estimated and correlated with the drug release rate. The model drug chosen for releasing studies is colchicine, a potential drug for gout disease treatment, currently in disuse because of its low therapeutic index. It is expected that the use of the control release procedure by drug encapsulation in this polymer overcomes this drawback. The synthesis of PVCL homopolymer and three VCL-co-PEGDA hydrogels varying the PEGDA crosslinker concentration was successfully carried out by emulsion polymerization. Their characterization was performed by DLS and FTIR spectroscopy. Polymerization yields were estimated by total solids analysis, and UV-VIS determined the cloud points. Finally, the drug loading and release over time were monitored by HPLC and UV-VIS spectroscopy showing that drug release profiles obtained corresponded to a sustained drug delivery system.

State of the art in nonthermal plasma processing for biomedical applications: Can it help fight viral pandemics like COVID-19?

Plasma processing finds widespread biomedical applications, such as the design of biosensors, antibiofouling surfaces, controlled drug delivery systems, and in plasma sterilizers. In the present coronavirus disease (COVID‐19) situation, the prospect of applying plasma processes like surface activation, plasma grafting, plasma‐enhanced chemical vapor deposition/plasma polymerization, surface etching, plasma immersion ion implantation, crosslinking, and plasma decontamination to provide timely solutions in the form of better antiviral alternatives, practical diagnostic tools, and reusable personal protective equipment is worth exploring. Herein, the role of nonthermal plasmas and their contributions toward healthcare are timely reviewed to engage different communities in assisting healthcare associates and clinicians, not only to combat the current COVID‐19 pandemic but also to prevent similar kinds of future outbreaks.

Robotics for enzyme technology: innovations and technological perspectives.

The use of robotics in the life science sector has created a considerable and significant impact on a wide range of research areas, including enzyme technology due to their immense applications in enzyme and microbial engineering as an indispensable tool in high-throughput screening applications. Scientists are experiencing the advanced applications of various biological robots (nanobots), fabricated based on bottom-up or top-down approaches for making nanotechnology scaffolds. Nanobots and enzyme-powered nanomotors are particularly attractive because they are self-propelled vehicles, which consume biocompatible fuels. These smart nanostructures are widely used as drug delivery systems for the efficient treatment of various diseases. This review gives insights into the escalating necessity of robotics and nanobots and their ever-widening applications in enzyme technology, including biofuel production and biomedical applications. It also offers brief insights into high-throughput robotic platforms that are currently being used in enzyme screening applications for monitoring and control of microbialgrowth conditions. KEY POINTS: • Robotics and their applications in biotechnology are highlighted. • Robotics for high-throughput enzyme screening and microbial engineering are described. • Nanobots and enzyme-powered nanomotors as controllable drug delivery systems are reviewed.

A promising dual-drug targeted delivery system in cancer therapy: nanocomplexes of folate–apoferritin-conjugated cationic solid lipid nanoparticles

Various nano-sized protein and lipid complexes are being investigated as drug delivery systems. The encapsulation of more than one drug in a single nanocomplex carrier could enhance the therapeutic potency and afford synergistic therapeutic effects. In this study, we developed a novel protein-lipid nanocomplex as a controlled drug delivery system for two important cancer drugs, doxorubicin (DOX) and mitoxantrone (MTO). Apoferritin (AFr) functionalized with folic acid (FA) was used to encapsulate DOX to create the targeted protein nanocomplexes (TPNs). The second drug, MTO, was loaded into the cationic solid lipid nanoparticles (cSLN) to form the liposomal drug nanocomplex particles (MTO-cSLNs). Two complexes were then assembled by tight coupling through ionic interactions to obtain the final drug delivery system, the dual-targeted protein-lipid nanocomplexes (DTPLNs). UV-Vis and fluorescence spectroscopy were used for structural characterization of TPNs and DTPLNs. Transmission electron microscopy (TEM) was used for comprehensive analysis of the final DTPLNs. We confirmed that the DTPLNs display desired time-dependent and pH-dependent drug release behaviors. We also demonstrated the improved anti-cancer efficacy of DOX and MTO in their encapsulated DTPLNs as compared to their free forms. Our results provide promising prospects for the application of the DTPLNs as efficient drug delivery systems.

In vivo therapeutic evaluation of a novel bis-lawsone derivative against tumor following delivery using mesoporous silica nanoparticle based redox-responsive drug delivery system

Herein, we have evaluated the in vivo therapeutic efficacy and systemic toxicity profile of a synthetic anticancer compound [3,3′-((4-(trifluoromethyl)phenyl)methylene)bis(2-hydroxynaphthalene-1,4-dione)]. A multifunctional mesoporous silica nanoparticle (MSN) based drug delivery network was also fabricated which specifically showed targeting nature towards the cancer cell. The mesopores of silica nanoparticles were tagged with phenyl boronic acid (PBA) for targeted drug delivery into tumor tissue. 1j was then loaded inside the nanocarriers followed by pore blocking with gold nanoparticles (GN) to attain a redox-responsive controlled drug delivery pattern. The synthesized nanocarriers (1j@-MSN-PBA-GN) having mean diameter of ~86 nm exhibited a moderate 1j loading content of 13.68% with overall negative surface charge. Both the targeted and non-targeted nanoformulations were tested for their anticancer activities both in vitro and in vivo models, and found more effective as compared with free 1j treatment. However, the targeted nanoformulations showed higher therapeutic effect due to increased cellular internalization and caused mitochondria-dependent apoptosis in MCF-7 cells via oxidative stress. Besides, the targeted nanoformulation significantly inhibited in the development of solid tumor in comparison to non-targeted nanoformulations and free 1j as a consequence of increased internalization of the drug-candidate in tumor tissue. Therefore, this study proposes that 1j can be considered as a potent anti-carcinogenic compound in vivo and its therapeutic potential is further increased by using PBA functionalized and GN gated MSN-based controlled drug delivery system without showing any significant systemic toxicity.

Bare Iron Oxide Nanoparticles as Drug Delivery Carrier for the Short Cationic Peptide Lasioglossin.

New drug delivery systems are a potential solution for administering drugs to reduce common side effects of traditional methods, such as in cancer therapy. Iron oxide nanoparticles (IONs) can increase the drugs’ biological activity through high binding efficiency and magnetically targeted drug delivery. Understanding the adsorption and release process of a drug to the carrier material plays a significant role in research to generate an applicable and controlled drug delivery system. This contribution focuses on the binding patterns of the peptide lasioglossin III from bee venom on bare IONs. Lasioglossin has a high antimicrobial behavior and due to its cationic properties, it has high binding potential. Considering the influence of pH, the buffer type, the particle concentration, and time, the highest drug loading of 22.7% is achieved in phosphate-buffered saline. Analysis of the desorption conditions revealed temperature and salt concentration sensitivity. The nanoparticles and peptide-ION complexes are analyzed with dynamic light scattering, zeta potential, and infrared spectroscopy. Additionally, cytotoxicity experiments performed on Escherichia coli show higher antimicrobial activity of bound lasioglossin than of the free peptide. Therefore, bare IONs are an interesting platform material for the development of drug-delivery carriers for cationic peptides.

Metal-organic frameworks for improving wound healing

• Recent advances in MOF materials for wound healing are comprehensively reviewed. • The physiological and pathological mechanisms in wound healing are emphasized. • Various MOF-based strategies for improving wound healing performance are discussed. • The current challenges and opportunities on the further studies are also proposed. Wound healing is the most important restorative process for injury to the skin and other tissues. In the process of wound healing, bacterial infection can easily lead to serious tissue damage. There is an urgent need to discover new drugs or methods to accelerate wound healing. Metal-organic frameworks (MOFs), a type of porous hybrid materials containing metal ions connected by organic ligands, have great potential in improving wound healing. Firstly, this review discusses the pathophysiology of complex wounds, current approaches to achieve healing in patients and the limitations of traditional methods. Then the review emphasizes the application of MOF materials in improving wound healing. MOF materials-based metal ion sustained-release systems can show long-term antibacterial effects or promote angiogenesis in the degradation process of MOFs. As an enzyme-like active material, it can be used to convert hydrogen peroxide into highly toxic hydroxyl groups to improve antibacterial efficiency in wounds. As a controlled drug delivery system for wound healing, it is important for MOFs to load drugs (molecular or gas therapeutic drugs), effectively inhibiting the growth of microorganisms or enhancing angiogenesis in the wound site. Moreover, MOF materials-based photoexcited systems can provide the potential of combining photodynamic therapy and photothermal therapy for bacterial infections. Lastly, the future challenges and directions of MOF materials in wound healing are also discussed.

A REVIEW ON MICROSPHERES AS A NOVEL CONTROLLED DRUG DELIVERY SYSTEM

Over the past three decades, controlled drug delivery systems have become more developed and play a key role in pharmaceuticals formulations. There are many shortcomings in Traditional or Conventional drug delivery systems like for maintaining desired therapeutic drug plasma concentration there is a need for frequent dosing for particular drugs having shorter half-lives. Furthermore, because of frequent dosing requirement, there is poor patient compliance which causes fluctuation in plasma concentration of the drug. The limitations of conventional drug delivery can be overcome by the development of novel drug delivery systems, of which the controlled drug delivery can maintain constant drug plasma concentration by slowly releasing the drug over an extended period. Developing controlled drug delivery systems can also improve the systemic bioavailability of the drug, thus enhancing the therapeutic efficacy of the drug and better patient compliance. There are many different approaches for such controlled delivery systems such as liposomes, niosomes, ethosomes, phytosomes, microemulsion, and microspheres. Among all the approaches microspheres are more convenient as the drug is slowly released from the polymeric matrix and the polymers used are mostly biodegradable and possess no side effects. Therefore, microspheres can be used in various medicinal departments such as oncology, gynecology, radiology, pulmonary, cardiology, diabetes, and vaccine therapy. This review article focuses on recent different types of microspheres along with their methods of preparation. The microspheres formulated can be later evaluated and characterized by different procedures.

Site-directed drug release performance in chemically-modified FeFe2O4 and CoFe2O4 magnetic nanoparticles for controlled drug delivery systems

This paper proposes a novel approach to the development of magnetic nanoparticles (MNPs) for drug delivery systems. The nanocarriers are made from FeFe2O4 and CoFe2O4 MNPs that were synthesized by combustion, coated with silica derivatives, and then conjugated to ciprofloxacin. The drug release tests were performed into simulated body fluid consisted of ciprofloxacin adsorbed onto MNPs composites with various mass ratios of hydroxyapatite:FeFe2O4 (M) and hydroxyapatite:CoFe2O4 (C), evaluated by pharmacokinetic models, and regression analysis. The MNPs were characterized by morphological and structural characterizations. Drug release was measured with a discontinuous method (paddle apparatus) and with a continuous method simulating a blood vessel. XRD and FTIR showed that all of the MNPs were successfully synthesized, coated, and drug conjugated. VSM exhibited superparamagnetic characteristics, with saturation magnetization varying between 9.74 and 32.90 emu/g and 9.65–30.00 emu/g for FeFe2O4 and CoFe2O4, respectively, as a function of the MNPs mass ratio on the nanocarrier. The discontinuous method showed drug release over 80% (FeFe2O4), while the CoFe2O4-based achieved over 40%, which indicates that the incorporation of hydroxyapatite favors the carrying of ciprofloxacin. The continuous method showed a drug release under 14% and 14.5% for the FeFe2O4 and CoFe2O4 based nanocarriers respectively, and this reduction of the desorbed drug compared to the discontinuous method may have occurred due to the action of the applied magnetic field. The mathematical model provided the release speed and time to reach the maximum fraction desorbed (<4 min), highlighted for M2 (13.8%) and C3 (14.5%) drug released, with a mass ratio of 50:50 and 30:70, respectively. The proposed continuous release model showed that the action of site-directed targeting significantly affected the amount of drug released. This identifies the optimal device for the development of magnetic nanoparticulate systems for drug delivery and tissue engineering.

Controlled Pulmonary Delivery of Carrier-Free Budesonide Dry Powder by Atomic Layer Deposition.

Ideal controlled pulmonary drug delivery systems provide sustained release by retarding lung clearance mechanisms and efficient lung deposition to maintain therapeutic concentrations over prolonged time. Here, we use atomic layer deposition (ALD) to simultaneously tailor the release and aerosolization properties of inhaled drug particles without the need for lactose carrier. In particular, we deposit uniform nanoscale oxide ceramic films, such as Al2O3, TiO2, and SiO2, on micronized budesonide particles, a common active pharmaceutical ingredient for the treatment of respiratory diseases. In vitro dissolution and ex vivo isolated perfused rat lung tests demonstrate dramatically slowed release with increasing nanofilm thickness, regardless of the nature of the material. Ex situ transmission electron microscopy at various stages during dissolution unravels mostly intact nanofilms, suggesting that the release mechanism mainly involves the transport of dissolution media through the ALD films. Furthermore, in vitro aerosolization testing by fast screening impactor shows a ∼2-fold increase in fine particle fraction (FPF) for each ALD-coated budesonide formulation after 10 ALD process cycles, also applying very low patient inspiratory pressures. The higher FPFs after the ALD process are attributed to the reduction in the interparticle force arising from the ceramic surfaces, as evidenced by atomic force microscopy measurements. Finally, cell viability, cytokine release, and tissue morphology analyses verify a safe and efficacious use of ALD-coated budesonide particles at the cellular level. Therefore, surface nanoengineering by ALD is highly promising in providing the next generation of inhaled formulations with tailored characteristics of drug release and lung deposition, thereby enhancing controlled pulmonary delivery opportunities.

Examining the Impact of Squaric Acid as a Crosslinking Agent on the Properties of Chitosan-Based Films.

Hydrogels based on chitosan are very versatile materials which can be used for tissue engineering as well as in controlled drug delivery systems. One of the methods for obtaining a chitosan-based hydrogel is crosslinking by applying different components. The objective of the present study was to obtain a series of new crosslinked chitosan-based films by means of solvent casting method. Squaric acid—3,4-dihydroxy-3-cyclobutene-1,2-dione—was used as a safe crosslinking agent. The effect of the squaric acid on the structural, mechanical, thermal, and swelling properties of the formed films was determined. It was established that the addition of the squaric acid significantly improved Young’s modulus, tensile strength, and thermal stability of the obtained materials. Moreover, it should be stressed that the samples consisting of chitosan and squaric acid were characterized by a higher swelling than pure chitosan. The detailed characterization proved that squaric acid could be used as a new effective crosslinking agent.

Poly ethylene glycol (PEG)-Related controllable and sustainable antidiabetic drug delivery systems.

Diabetes mellitus is one of the most challenging threats to global public health. To improve the therapy efficacy of antidiabetic drugs, numerous drug delivery systems have been developed. Polyethylene glycol (PEG) is a polymeric family sharing the same skeleton but with different molecular weights which is considered as a promising material for drug delivery. In the delivery of antidiabetic drugs, PEG captures much attention in the designing and preparation of sustainable and controllable release systems due to its unique features including hydrophilicity, biocompatibility and biodegradability. Due to the unique architecture, PEG molecules are also able to shelter delivery systems to decrease their immunogenicity and avoid undesirable enzymolysis. PEG has been applied in plenty of delivery systems such as micelles, vesicles, nanoparticles and hydrogels. In this review, we summarized several commonly used PEG-contained antidiabetic drug delivery systems and emphasized the advantages of stimuli-responsive function in these sustainable and controllable formations.

Computational modelling of nanotube delivery of anti-cancer drug into glutathione reductase enzyme

Density functional theory method combined with docking and molecular dynamics simulations are used to understand the interaction of carmustine with human glutathione reductase enzyme. The active site of the enzyme is evaluated by docking simulation is used for molecular dynamics simulation to deliver the carmustine molecule by (5,5) single walled carbon nanotube (SWCNT). Our model of carmustine in the active site of GR gives a negative binding energy that is further refined by QM/MM study in gas phase and solvent phase to confirm the stability of the drug molecule inside the active site. Once released from SWCNT, carmustine forms multiple polar and non-polar hydrogen bonding interactions with Tyr180, Phe209, Lys318, Ala319, Leu320, Leu321, Ile350, Thr352 and Val354 in the range of 2–4 Å. The SWCNT vehicle itself is held fix at its place due to multiple pi-pi stacking, pi-amide, pi-sigma interactions with the neighboring residues. These interactions in the range of 3–5 Å are crucial in holding the nanotube outside the drug binding region, hence, making an effective delivery. This study can be extended to envisage the potential applications of computational studies in the modification of known drugs to find newer targets and designing new and improved controlled drug delivery systems.

TEMPO-Oxidized Cellulose Beads as Potential pH-Responsive Carriers for Site-Specific Drug Delivery in the Gastrointestinal Tract.

The development of controlled drug delivery systems based on bio-renewable materials is an emerging strategy. In this work, a controlled drug delivery system based on mesoporous oxidized cellulose beads (OCBs) was successfully developed by a facile and green method. The introduction of the carboxyl groups mediated by the TEMPO(2,2,6,6-tetramethylpiperidine-1-oxyradical)/NaClO/NaClO2 system presents the pH-responsive ability to cellulose beads, which can retain the drug in beads at pH = 1.2 and release at pH = 7.0. The release rate can be controlled by simply adjusting the degree of oxidation to achieve drug release at different locations and periods. A higher degree of oxidation corresponds to a faster release rate, which is attributed to a higher degree of re-swelling and higher hydrophilicity of OCBs. The zero-order release kinetics of the model drugs from the OCBs suggested a constant drug release rate, which is conducive to maintaining blood drug concentration, reducing side effects and administration frequency. At the same time, the effects of different model drugs and different drug-loading solvents on the release behavior and the physical state of the drugs loaded in the beads were studied. In summary, the pH-responsive oxidized cellulose beads with good biocompatibility, low cost, and adjustable release rate have shown great potential in the field of controlled drug release.

A Brief Review on Controlled Drug Delivery System

A Brief Review on Controlled Drug Delivery System