SUSTAINED RELEASE OF INSULIN FROM POLOXAMER GELS INTERPENETRATED BY POLYION COMPLEXATION OF CHITOSAN-HYALURONIC ACID NETWORK

2010 ◽  
Vol 22 (06) ◽  
pp. 475-480
Author(s):  
Ming-Chia Yang ◽  
Jiun-Sheng Yang ◽  
Yi-You Huang ◽  
Ming-Jium Shieh ◽  
Tze-Wen Chung
Keyword(s):  
Drug Delivery ◽  
Hyaluronic Acid ◽  
Sustained Release ◽  
Insulin Release ◽  
Burst Release ◽  
Protein Drug ◽  
Initial Burst ◽  
Initial Burst Release ◽  
Protein Drug Delivery

This study investigates in vitro the protein drug delivery characteristics of new thermal sensitive gels, poloxamer (P)–chitosan (CS)/hyaluronic acid (HA) gels (P–CS/HA), in which a CS solution is interacting with various concentrations of HA that interpenetrates P gels. The polyion complexation occurs between CS and HA that can protect drugs from proteolysis. The results indicate that the swelling ratios of all P–CS/HA gels are markedly superior to those of nonswelling P and P–CS gels. For example, P–CS/HA (0.5% (w/w)) gels have swelling ratios of 48.3 ± 2.7% (w/w), which are maintained for approximately 0.5 h in water at 37°C. In vitro releases of insulin from P–CS/HA (0.5% (w/w)) gels had significantly lowered initial burst release (P < 0.01) and lasted much longer than those from gels without a CS network. The duration of insulin release was in a significantly sustained manner for up to 3.5 h, which was about two times or longer than the period of delivery using P or P–CS gels.

scholarly journals Subcutaneously Injectable Hyaluronic Acid Hydrogel for Sustained Release of Donepezil with Reduced Initial Burst Release: Effect of Hybridization of Microstructured Lipid Carriers and Albumin

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 864
Author(s):  
Nae-Won Kang ◽  
So-Yeon Yoon ◽  
Sungho Kim ◽  
Na-Young Yu ◽  
Ju-Hwan Park ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Hyaluronic Acid ◽  
Sustained Release ◽  
Subcutaneous Administration ◽  
Burst Release ◽  
Initial Burst ◽  
Initial Burst Release ◽  
Ache Inhibitors ◽  
Hyaluronic Acid Hydrogel

The daily oral administration of acetylcholinesterase (AChE) inhibitors for Alzheimer’s disease features low patient compliance and can lead to low efficacy or high toxicity owing to irregular intake. Herein, we developed a subcutaneously injectable hyaluronic acid hydrogel (MLC/HSA hydrogel) hybridized with microstructured lipid carriers (MLCs) and human serum albumin (HSA) for the sustained release of donepezil (DNP) with reduced initial burst release. The lipid carrier was designed to have a microsized mean diameter (32.6 ± 12.8 µm) to be well-localized in the hydrogel. The hybridization of MLCs and HSA enhanced the structural integrity of the HA hydrogel, as demonstrated by the measurements of storage modulus (G′), loss modulus (G″), and viscosity. In the pharmacokinetic study, subcutaneous administration of MLC/HSA hydrogel in rats prolonged the release of DNP for up to seven days and reduced the initial plasma concentration, where the Cmax value was 0.3-fold lower than that of the control hydrogel without a significant change in the AUClast value. Histological analyses of the hydrogels supported their biocompatibility for subcutaneous injection. These results suggest that a new hybrid MLC/HSA hydrogel could be promising as a subcutaneously injectable controlled drug delivery system for the treatment of Alzheimer’s disease.

The effect of crosslinking agent on sustained release of bFGF–collagen microspheres

RSC Advances ◽  
2015 ◽  
Vol 5 (44) ◽  
pp. 34511-34516 ◽  
Author(s):  
Ting Liu ◽  
Nianhua Dan ◽  
Weihua Dan
Keyword(s):  
Drug Delivery ◽  
Sustained Release ◽  
Drug Delivery Systems ◽  
Crosslinking Agent ◽  
Delivery Systems ◽  
Burst Release ◽  
Initial Burst ◽  
Initial Burst Release

Initial burst release and loss of bioactivity of drugs are the shortcomings of drug delivery systems (DDSs) used for in vivo treatment.

scholarly journals Drug Delivery Applications of Core-Sheath Nanofibers Prepared by Coaxial Electrospinning: A Review

Pharmaceutics ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 305 ◽  
Author(s):  
Bishweshwar Pant ◽  
Mira Park ◽  
Soo-Jin Park
Keyword(s):  
Drug Delivery ◽  
Electrospun Nanofibers ◽  
Coaxial Electrospinning ◽  
Burst Release ◽  
High Porosity ◽  
Nanofiber Membrane ◽  
Initial Burst ◽  
Initial Burst Release ◽  
Small Pore ◽  
Drug Delivery Applications

Electrospinning has emerged as one of the potential techniques for producing nanofibers. The use of electrospun nanofibers in drug delivery has increased rapidly over recent years due to their valuable properties, which include a large surface area, high porosity, small pore size, superior mechanical properties, and ease of surface modification. A drug loaded nanofiber membrane can be prepared via electrospinning using a model drug and polymer solution; however, the release of the drug from the nanofiber membrane in a safe and controlled way is challenging as a result of the initial burst release. Employing a core-sheath design provides a promising solution for controlling the initial burst release. Numerous studies have reported on the preparation of core-sheath nanofibers by coaxial electrospinning for drug delivery applications. This paper summarizes the physical phenomena, the effects of various parameters in coaxial electrospinning, and the usefulness of core-sheath nanofibers in drug delivery. Furthermore, this report also highlights the future challenges involved in utilizing core-sheath nanofibers for drug delivery applications.

scholarly journals Thermosensitive Chitosan Hydrogels Containing Polymeric Microspheres for Vaginal Drug Delivery

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Ting-Ting Yang ◽  
Yuan-Zheng Cheng ◽  
Meng Qin ◽  
Yong-Hong Wang ◽  
Hong-Li Yu ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Sustained Release ◽  
Delivery System ◽  
Drug Loading ◽  
Great Promise ◽  
Burst Release ◽  
Bletilla Striata ◽  
Vaginal Drug Delivery ◽  
Thermosensitive Hydrogels

Thermosensitive hydrogels have increasingly received considerable attention for local drug delivery based on many advantages. However, burst release of drugs is becoming a critical challenge when the hydrogels are employed. Microspheres- (MS-) loaded thermosensitive hydrogels were thus fabricated to address this limitation. Employing an orthogonal design, the spray-dried operations of tenofovir (TFV)/Bletilla striata polysaccharide (BSP)/chitosan (CTS) MS were optimized according to the drug loading (DL). The physicochemical properties of the optimal MS (MS F) were characterized. Depending on the gelation temperature and gelating time, the optimal CTS-sodium alginate- (SA-) α,β-glycerophosphate (GP) (CTS-SA-GP) hydrogel was obtained. Observed by scanning electron microscope (SEM), TFV/BSP/CTS MS were successfully encapsulated in CTS-SA-GP. In vitro releasing demonstrated that MS F-CTS-SA-GP retained desirable in vitro sustained-release characteristics as a vaginal delivery system. Bioadhesion measurement showed that MS-CTS-SA-GP exhibited the highest mucoadhesive strength. Collectively, MS-CTS-SA-GP holds great promise for topical applications as a sustained-release vaginal drug delivery system.

Sucrose Acetate Isobutyrate as an In situ Forming Implant for Sustained Release of Local Anesthetics

2019 ◽  
Vol 16 (4) ◽  
pp. 331-340
Author(s):  
Hanmei Li ◽  
Yuling Xu ◽  
Yuna Tong ◽  
Yin Dan ◽  
Tingting Zhou ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Sustained Release ◽  
Local Anesthetics ◽  
Subcutaneous Injection ◽  
In Vitro Release ◽  
Pharmacokinetic Analysis ◽  
Burst Release

Objective: In this study, an injectable Sucrose Acetate Isobutyrate (SAIB) drug delivery system (SADS) was designed and fabricated for the sustained release of Ropivacaine (RP) to prolong the duration of local anesthesia. Methods: By mixing SAIB, RP, and N-methyl-2-pyrrolidone, the SADS was prepared in a sol state with low viscosity before injection. After subcutaneous injection, the pre-gel solution underwent gelation in situ to form a drug-released depot. Result: The in vitro release profiles and in vivo pharmacokinetic analysis indicated that RP-SADS had suitable controlled release properties. Particularly, the RP-SADS significantly reduced the initial burst release after subcutaneous injection in rats. Conclusion: In a pharmacodynamic analysis of rats, the duration of nerve blockade was prolonged by over 3-fold for the RP-SADS formulation compared to RP solution. Additionally, RP-SADS showed good biocompatibility in vitro and in vivo. Thus, the SADS-based depot technology is a safe drug delivery strategy for the sustained release of local anesthetics with long-term analgesia effects.

Understanding the burst release phenomenon: toward designing effective nanoparticulate drug-delivery systems

2020 ◽  
pp. 00-00
Author(s):  
Sourav Bhattacharjee
Keyword(s):  
Drug Delivery ◽  
Sustained Release ◽  
Mathematical Models ◽  
Drug Delivery Systems ◽  
Release Kinetics ◽  
Burst Release ◽  
Future Directions ◽  
Short Period

Burst release of encapsulated drug with release of a significant fraction of payload into release medium within a short period, both in vitro and in vivo, remains a challenge for translation. Such unpredictable and uncontrolled release is often undesirable, especially from the perspective of developing sustained-release formulations. Moreover, a brisk release of the payload upsets optimal release kinetics. This account strives toward understanding burst release noticed in nanocarriers and investigates its causes. Various mathematical models to explain such untimely release were also examined, including their strengths and weaknesses. Finally, the account revisits current techniques of limiting burst release from nanocarriers and prioritizes future directions that harbor potential of fruitful translation by reducing such occurrences.

Novel Electrospun Bicomponent Scaffolds for Bone Tissue Engineering: Fabrication, Characterization and Sustained Release of Growth Factor

2012 ◽  
Vol 1418 ◽  
Author(s):  
Chong Wang ◽  
Min Wang ◽  
Xiao-Yan Yuan
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Biological Tissues ◽  
Osteoblastic Cell ◽  
Burst Release ◽  
Electrospinning Technique ◽  
Initial Burst ◽  
Initial Burst Release

ABSTRACTElectrospinning is a versatile technique for fabricating three-dimensional (3D) nanofibrous scaffolds and the scaffolds have been found to elicit desirable cellular behavior for tissue regeneration because the nanofibrous structures mimic the nanofibrous extracellular matrix (ECM) of biological tissues. From the material point of view, the ECM of bone is a nanofibrous nanocomposite consisting of an organic matrix (mainly collagen) and inorganic bone apatite nanoparticles. Therefore, for bone tissue engineering scaffolds, it is natural to construct nanofibrous nanocomposites having a biodegradable polymer matrix and nanosized bioactive bioceramics. Our previous studies demonstrated: (1) electrospun nanocomposite fiber loaded with calcium phosphate (Ca-P) were osteoconductive and could promote osteoblastic cell proliferation and differentiation better than pure polymer fibers; (2) The controlled release of recombinant human bone morphogenetic protein (rhBMP-2) from scaffolds provided the scaffolds with desired osteoinductivity. In the current investigation, novel bicomponent scaffolds for bone tissue engineering were produced using our established dual-source dual-power electrospinning technique to achieve both osteoconductivity and osteoinductivity. In the bicomponent scaffolds, one fibrous component was electrospun Ca-P/PLGA nanocomposite fibers and the other component was emulsion electrospun PDLLA nanofibers incorporated with rhBMP-2. Through electrospinning optimization, both fibers were evenly distributed in bicomponent scaffolds. The mass ratio of rhBMP-2/PDLLA fibers to Ca-P/PLGA fibers in bicomponent scaffolds could be controlled using multiple syringes. The structure and morphology of mono- and bicomponent scaffolds were examined. The in vitro release of rhBMP-2 from mono- and bicomponent scaffolds showed different release amount but similar release profile, exhibiting an initial burst release. Blending PDLLA with polyethylene glycol (PEG) could reduce the initial burst release of rhBMP-2.

In vitro drug release and antibacterial activity evaluation of silk fibroin coated vancomycin hydrochloride loaded poly (lactic-co-glycolic acid) (PLGA) sustained release microspheres

2022 ◽  
pp. 088532822110640
Author(s):  
Shengtang Li ◽  
Xuewen Shi ◽  
Bo Xu ◽  
Jian Wang ◽  
Peng Li ◽  
...  
Keyword(s):  
Drug Release ◽  
Encapsulation Efficiency ◽  
Glycolic Acid ◽  
Drug Loading ◽  
Burst Release ◽  
Plga Microspheres ◽  
In Vitro Drug Release ◽  
Initial Burst ◽  
Initial Burst Release

Currently, the treatment of osteomyelitis poses a great challenge to clinical orthopedics. The use of biodegradable materials combined with antibiotics provides a completely new option for the treatment of osteomyelitis. In this study, vancomycin hydrochloride (VANCO) loaded poly (lactic-co-glycolic acid) (PLGA) microspheres were prepared by a double emulsion solvent evaporation method, and the in vitro drug release behaviors of the drug loaded microspheres were explored after coating with different concentrations of silk fibroin (SF). Drug loading, encapsulation efficiency, Scanning electron microscopy, particle size analysis, Fourier transform infrared spectroscopy, hydrophilicity, in vitro drug release, and in vitro antibacterial activity were evaluated. The results showed that the drug loading of vancomycin loaded PLGA microspheres was (24.11 ±1.72)%, and the encapsulation efficiency was (48.21 ±3.44)%. The in vitro drug release indicated that the drug loaded microspheres showed an obvious initial burst release, and the drug loaded microspheres coated with SF could alleviate the initial burst release in varying degrees. It also can reduce the amount of cumulative drug release, and the effect of microspheres coated with 0.1% concentration of SF is the best. The time of in vitro drug release in different groups of drug loaded microspheres can be up to 28 days. The microspheres coated with (0.1%SF) or without (0%SF) SF showed a cumulative release of (82.50±3.51)% and (67.70±3.81)%,respectively. Therefore, the surface coating with SF of vancomycin loaded microspheres can alleviate the initial burst release, reduce the cumulative drug release, potentially prolong the drug action time, and improve the anti-infection effect.

The impacts of PLGA/PEG triblock copolymers with variable molecular weights on sustained release of buprenorphine

2021 ◽  
Vol 18 ◽  
Author(s):  
Hossein Kamali ◽  
Elham Khodaverdi ◽  
Fatemeh Mohammadpour ◽  
Ali Kakavand ◽  
Seyedeh Nesa Rezaeian Shiadeh ◽  
...  
Keyword(s):  
Sustained Release ◽  
Sol Gel ◽  
In Vitro Release ◽  
Burst Release ◽  
Sustained Release Formulation ◽  
Melting Method ◽  
Initial Burst ◽  
Initial Burst Release ◽  
Molecular Weights

Introduction: Current in-situ injectable implants of buprenorphine (BP) such as Sublocade® consist of N-methyl-2-pyrrolidone (NMP)-dissolved PLGA. To control the initial burst release of Sublocade® during the first 24 hours after injection, we used a BP in-situ forming composite (ISFC) to employ different molecular weights of PLGA-PEG-PLGA triblock. Methods: The triblock was synthesized by ring-opening polymerization (ROP) using PEG molecules with weights of 1500, 3000, and 4000 Da via the melting method. The specifications of the triblock were evaluated by 1H-NMR, FTIR, GPC, and DSC. The sol-gel, gel-precipitate temperatures, in-vitro release, and composites’ morphology, degradation, and toxicity were assessed for determining the features of ISFC 1500, ISFC 3000, and ISFC 4000 formulations. ROP was performed successfully via the melting method. The yields of all polymerization reactions were greater than 83.4 %. Results: The PEG 1500 triblock showed both sol-gel and gel-precipitate temperatures, but PEG 3000 and 4000 only showed a sol-precipitate temperature. The values of initial burst release of BP from ISFC 1500, ISFC 3000, and ISFC 4000 were 6.52 ± 0.22 %, 12.39 ± 0.61 %, and 15.80 ± 0.98 %, respectively. BP release from the ISFCs was completed over three weeks for ISFC 1500 and 10 days for ISFC 3000 and ISFC 4000. The composites containing PEG 3000 and PEG 4000 were more spongy and porous than PEG 1500. The ISFC 1500 delivered a higher cell viability (95.17 ± 1.15 %) compared with ISFC 3000 (86.37 ± 2.25%) and ISFC 4000 (79.70 ± 3.77%). Conclusion: These results indicated that ISFC 1500 were biocompatible and delivered suitable early initial burst reactions compared with ISFC 3000 and 4000 and might be a good candidate for preparing sustained-release formulation of BP.

scholarly journals PLGA Microspheres with Alginate-Coated Large Pores for the Formulation of an Injectable Depot of Donepezil Hydrochloride

Pharmaceutics ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 311
Author(s):  
Dohyun Kim ◽  
Tae Hee Han ◽  
Seong-Chul Hong ◽  
Sun Jae Park ◽  
Yong Hak Lee ◽  
...  
Keyword(s):  
Sustained Release ◽  
Patient Compliance ◽  
Calcium Alginate ◽  
Burst Release ◽  
Plga Microspheres ◽  
Large Space ◽  
Initial Burst ◽  
Initial Burst Release ◽  
Donepezil Hydrochloride ◽  
Alginate Coating

As the main symptom of Alzheimer’s disease-related dementia is memory loss, patient compliance for donepezil hydrochloride (donepezil), administered as once-daily oral formulations, is poor. Thus, we aimed to design poly(lactic-co-glycolic acid) (PLGA) microspheres (MS) with alginate-coated large pores as an injectable depot of donepezil exhibiting sustained release over 2–3 weeks. The PLGA MS with large pores could provide large space for loading drugs with high loading capacity, and thereby sufficient amounts of drugs were considered to be delivered with minimal use of PLGA MS being injected. However, initial burst release of donepezil from the porous PLGA MS was observed. To reduce this initial burst release, the surface pores were closed with calcium alginate coating using a spray-ionotropic gelation method. The final pore-closed PLGA MS showed in vitro sustained release for approximately 3 weeks, and the initial burst release was remarkably decreased by the calcium alginate coating. In the prediction of plasma drug concentration profiles using convolution method, the mean residence time of the pore-closed PLGA MS was 2.7-fold longer than that of the porous PLGA MS. Therefore, our results reveal that our pore-closed PLGA MS formulation is a promising candidate for the treatment of dementia with high patient compliance.

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