scholarly journals Novel Poly(L-lactide-co-ε-caprolactone) Matrices Obtained with the Use of Zr[Acac]4as Nontoxic Initiator for Long-Term Release of Immunosuppressive Drugs

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Katarzyna Jelonek ◽  
Janusz Kasperczyk ◽  
Suming Li ◽  
Piotr Dobrzynski ◽  
Henryk Janeczek ◽  
...  

Slowly degradable copolymers of L-lactide andε-caprolactone can provide long-term delivery and may be interesting as alternative release systems of cyclosporine A (CyA) and rapamycin (sirolimus), in which available dosage forms cause a lot of side effects. The aim of this study was to obtain slowly degradable matrices containing immunosuppressive drug from PLACL initiated by nontoxic Zr[Acac]4. Three kinds of poly(L-lactide-co-ε-caprolactone) (PLACL) matrices with different copolymer chain microstructure were used to compare the release process of cyclosporine A and rapamycine. The influence of copolymer chain microstructure on drug release rate and profile was also analyzed. The determined parameters could be used to tailor drug release by synthesis of demanded polymeric drug carrier. The studied copolymers were characterized at the beginning and during the degradation process of the polymeric matrices by NMR spectroscopy, GPC (gel permeation chromatography), and DSC (differential scanning calorimetry). Different drug release profiles have been observed from each kind of copolymer. The correlation between drug release process and changes of copolymer microstructure during degradation process was noticed. It was determined that different copolymer composition (e.g., lower amount of caprolactone units) does not have to influence the drug release, but even small changes in copolymer randomness affect this process.

Author(s):  
Pravin S Patil ◽  
Shashikant C Dhawale

 Objective: The purpose of the present investigation was to develop a nanosuspension to improve dissolution rate and oral bioavailability of ritonavir.Methods: Extended-release ritonavir loaded nanoparticles were prepared using the polymeric system by nanoprecipitation technique. Further, the effect of Eudragit RL100 (polymeric matrix) and polyvinyl alcohol (surfactant) was investigated on particle size and distribution, drug content, entrapment efficiency, and in vitro drug release from nanosuspension where a strong influence of polymeric contents was observed. Drug-excipient compatibility and amorphous nature of drug in prepared nanoparticles were confirmed by Fourier transform infrared spectroscopy, differential scanning calorimetry, and powder X-ray diffraction studies, respectively.Results: Hydrophobic portions of Eudragit RL100 could result in enhanced encapsulation efficiency. However, increase in polymer and surfactant contents lead to enlarged particle size proportionately as confirmed by transmission electron microscopy. Nanosuspension showed a significant rise in dissolution rate with complete in vitro drug release as well as higher bioavailability in rats compared to the pure drug.Conclusion: The nanoprecipitation technique used in present research could be further explored for the development of different antiretroviral drug carrier therapeutics.


2019 ◽  
Vol 16 (3) ◽  
pp. 242-253 ◽  
Author(s):  
Kaleem Ullah ◽  
Muhammad Sohail ◽  
Abdul Mannan ◽  
Haroon Rashid ◽  
Aamna Shah ◽  
...  

Objective: The study describes the development of chitosan-based (AMPS-co-AA) semi-IPN hydrogels using free radical polymerization technique. Methods: The resulting hydrogels were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), X-Ray diffraction (XRD), and Scanning Electron Microscopy (SEM). The successful crosslinking of chitosan, 2- Acrylamido-2-Methylpropane Sulfonic Acid (AMPS), and Acrylic Acid (AA) was confirmed by FT IR. Unloaded and drug-loaded hydrogels exhibited higher thermal stability after crosslinking compared to the individual components. XRD confirmed the decrease in crystallinity after hydrogel formation and molecular dispersion of Oxaliplatin (OXP) in the polymeric network. SEM showed rough, vague and nebulous surface resulting from crosslinking and loading of OXP. Results: The experimental results revealed that swelling and drug release were influenced by the pH of the medium being low at acidic pH and higher at basic pH. Increasing the concentration of chitosan and AA enhanced the swelling, drug loading and drug release while AMPS was found to act inversely. Conclusion: It was confirmed that the hydrogels were degraded more by specific enzyme lysozyme as compared to the non-specific enzyme collagenase. In-vitro cytotoxicity suggested that the unloaded hydrogels were non-cytotoxic while crude drug and drug-loaded hydrogel exhibited dose-dependent cytotoxicity against HCT-116 and MCF-7. Results of acute oral toxicity on rabbits demonstrated that the hydrogels are non-toxic up to 3900 mg/kg after oral administration, as no toxicity or histopathological changes were observed in comparison to control rabbits. These pH-sensitive hydrogels appear to provide an ideal basis as a safe carrier for oral drug delivery.


2019 ◽  
Vol 4 (4) ◽  
pp. 155-162
Author(s):  
Fatemeh Dalayi ◽  
Leila Hajiaghababaei ◽  
Alireza Badiei ◽  
Elham Boorboor Azimi ◽  
Mohammad Reza Ganjali ◽  
...  

Introduction: Ordered nanoporous silica such as SBA-15 has a great potential for application in controlled drug release systems. Chemical modification of the silanol groups of SBA-15 allows better control over drug loading and release. Therefore, tris(2-aminoethyl) amine-functionalized mesoporous silica SBA-15 was evaluated as a potential carrier for the delivery of citalopram. Methods: Tris (2-aminoethyl) amine-functionalized SBA-15 was synthesized and characterized by various methods. Citalopram was loaded on the functionalized SBA-15 and drug release into simulated body fluid (SBF) solution and phosphate buffers was investigated. Results: The optimal condition for loading of the citalopram was obtained at pH = 9 after stirring for 5 minutes. The release profile of citalopram was monitored in phosphate buffers with three different pH values of 5, 7, and 8. A faster release rate at lower pH value was observed, suggesting a weaker interaction because of the protonation of the amino group of the functionalized SBA15. The average release rate of citalopram from each gram of functionalized SBA-15 was 12 µg h-1 in the SBF. Conclusion: The results showed that loading amount and release rate of citalopram depended on pH value and the release process showed a very slow release pattern. Therefore, tris (2-aminoethyl) amine-functionalized SBA-15 is a suitable carrier for controlled release of citalopram and has a great potential for disease therapy.


2018 ◽  
Vol 90 (6) ◽  
pp. 1073-1084 ◽  
Author(s):  
Norul Nazilah Ab’lah ◽  
Nagarjun Konduru Venkata ◽  
Tin Wui Wong

Abstract Starch is constituted of amylose and amylopectin. Debranching of amylopectin converts it into amylose thereby producing resistant starch which is known to be less digestible by the amylase. This study designed resistant starch using acid hydrolysis and heat-moisture treatment methods with native corn starch as the starting material. Both native and processed starches were subjected to Fourier transform infrared spectroscopy, X-ray diffractometry, differential scanning calorimetry and molecular weight analysis. They were nanospray-dried into nanoparticles with 5-fluorouracil as the drug of interest for colon cancer treatment. These nanoparticles were subjected to size, zeta potential, morphology, drug content and in vitro drug release analysis. Heat-moisture treatment of native corn starch enabled the formation of resistant starch through amylopectin debranching and molecular weight reduction thereby enhancing hydrogen bonding between the starch molecules at the amorphous phase and gelatinization capacity. The nanoparticles prepared from resistant starch demonstrated similar drug release as those of native starch in spite of the resistant starch had a lower molecular weight. The resistant starch is envisaged to be resistant to the digestive action of amylase in intestinal tract without the formed nanoparticles exhibiting excessively fast drug release in comparison to native starch. With reduced branching, it represents an ideal precursor for targeting ligand conjugation in design of oral colon-specific nanoparticulate drug carrier.


2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Quan Vo-An ◽  
Thuy Chinh Nguyen ◽  
Quang Tung Nguyen ◽  
Quoc Trung Vu ◽  
Cong Doanh Truong ◽  
...  

Recently, plenty of interesting studies on improvement of bioavailability for poorly soluble drugs were implemented with different approaches such as using of combined biopolymers as a delivery system that allowed to enhancing drug solubility and bioavailability. In this work, alginate and chitosan were blended together in the form of polymeric particles, loaded with both lovastatin and ginsenoside Rb1 to producing the four-component nanoparticles by ionic gelation method. CaCl2 and sodium tripolyphosphate were used as gelation agent and cross-linking agent, respectively. The characteristics of obtained nanoparticles were studied by means of infrared spectra (IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and dynamic light scattering (DLS). In combination, ginsenoside Rb1 and lovastatin both interacted with each other to improve the drug release ability of the polymer particles. The change of initial content of drugs in the nanoparticles has a negligible effect on the functional groups in the structure of the nanoparticles but has a significant impact on drug release process of both lovastatin and ginsenoside Rb1 from the nanoparticles in selective simulated body fluids. In addition, the synergistic interaction of lovastatin and ginsenoside Rb1 could be also observed through the modification of relative crystal degree and drug release efficiency.


2009 ◽  
Vol 79-82 ◽  
pp. 1431-1434 ◽  
Author(s):  
Ya Kai Feng ◽  
Shi Feng Zhang ◽  
Li Zhang ◽  
Jin Tang Guo ◽  
Yong Shen Xu

In this paper, the release of model drug aspirin (ASP) from biodegradable polyesterurethane networks was studied. Poly(D,L-lactide-co-glycolide)urethane (PULG) networks were prepared from hydroxyl telechelic star-shaped oligo(D,L-lactide-co-glycolide) coupled with 1,6-diisocyanate-2,2,4-trimethylhexane and 1,6-diisocyanate-2,4,4-trimethylhexane or isophorone diisocyanate. PULG networks turned from transparent to opaque after ASP loading. PULG networks with lower crosslinking density always resulted in higher drug loaded content. The results of differential scanning calorimetry (DSC) and scanning electron microscope (SEM) measurements demonstrated that ASP was uniformly distributed in the networks. The drug release courses of ASP from PULG networks in phosphate buffered saline pH = 7.0 at 37 °C could be divided into three stages. Firstly, ASP release was at approximately uniform rate from PULG networks; Secondly, the release rate obviously increased for the degradation of the PULG networks; Thirdly, the release rate decreased gradually because most of the ASP had diffused out of the PULG networks. The crosslinking density of polyesterurethane networks also affected drug release rate. The in vitro release test revealed that ASP accelerated the degradation process of PULG, which exhibited a typical erosion-controlled release mechanism.


2020 ◽  
Vol 17 (6) ◽  
pp. 511-522 ◽  
Author(s):  
Alicia Graciela Cid ◽  
María Verónica Ramírez-Rigo ◽  
María Celeste Palena ◽  
Elio Emilio Gonzo ◽  
Alvaro Federico Jimenez-Kairuz ◽  
...  

Background: Mathematical modeling in modified drug release is an important tool that allows predicting the release rate of drugs in their surrounding environment and elucidates the transport mechanisms involved in the process. Objective: The aim of this work was to develop a mathematical model that allows evaluating the release profile of drugs from polymeric carriers in which the swelling phenomenon is present. Methods: Swellable matrices based on ionic complexes of alginic acid or carboxymethylcellulose with ciprofloxacin were prepared and the effect of adding the polymer sodium salt on the swelling process and the drug release was evaluated. Experimental data from the ciprofloxacin release profiles were mathematically adjusted, considering the mechanisms involved in each stage of the release process. Results: A proposed model, named “Dual Release” model, was able to properly fit the experimental data of matrices presenting the swelling phenomenon, characterized by an inflection point in their release profile. This entails applying the extended model of Korsmeyer-Peppas to estimate the percentage of drug released from the first experimental point up to the inflection point and then a model called Lumped until the final time, allowing to adequately represent the complete range of the drug release profile. Different parameters of pharmaceutical relevance were calculated using the proposed model to compare the profiles of the studied matrices. Conclusion: The “Dual Release” model proposed in this article can be used to predict the behavior of complex systems in which different mechanisms are involved in the release process.


2020 ◽  
Vol 17 ◽  
Author(s):  
Anisha D’Souza ◽  
Ranjita Shegokar

: In recent years, SLNs and NLCs are among the popular drug delivery systems studied for delivery of lipophilic drugs. Both systems have demonstrated several beneficial properties as an ideal drug-carrier, optimal drug-loading and good long-term stability. NLCs are getting popular due to their stability advantages and possibility to load various oil components either as an active or as a matrix. This review screens types of oils used till date in combination with solid lipid to form NLCs. These oils are broadly classified in two categories: Natural oils and Essential oils. NLCs offer range advantages in drug delivery due to the formation of imperfect matrix owing to the presence of oil. The type and percentage of oil used determines optimal drug loading and stability. Literature shows that variety of oils is used in NLCs mainly as matrix, which is from natural origin, triglycerides class. On the other hand, essential oils not only serve as a matrix but as an active. In short, oil is the key ingredient in formation of NLCs, hence needs to be selected wisely as per the performance criteria expected.


2020 ◽  
Vol 17 (3) ◽  
pp. 246-256
Author(s):  
Kriti Soni ◽  
Ali Mujtaba ◽  
Md. Habban Akhter ◽  
Kanchan Kohli

Aim: The intention of this investigation was to develop Pemetrexed Diacid (PTX)-loaded gelatine-cloisite 30B (MMT) nanocomposite for the potential oral delivery of PTX and the in vitro, and ex vivo assessment. Background: Gelatin/Cloisite 30 B (MMT) nanocomposites were prepared by blending gelatin with MMT in aqueous solution. Methods: PTX was incorporated into the nanocomposite preparation. The nanocomposites were investigated by Fourier Transmission Infra Red Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC), Scanning Electron Microscope (SEM) X-Ray Diffraction (XRD) and Confocal Laser Microscopy (CLSM). FT-IR of nanocomposite showed the disappearance of all major peaks which corroborated the formation of nanocomposites. The nanocomposites were found to have a particle size of 121.9 ± 1.85 nm and zeta potential -12.1 ± 0.63 mV. DSC thermogram of drug loaded nanocomposites indicated peak at 117.165 oC and 205.816 oC, which clearly revealed that the drug has been incorporated into the nanocomposite because of cross-linking of cloisite 30 B and gelatin in the presence of glutaraldehyde. Results: SEM images of gelatin show a network like structure which disappears in the nanocomposite. The kinetics of the drug release was studied in order to ascertain the type of release mechanism. The drug release from nanocomposites was in a controlled manner, followed by first-order kinetics and the drug release mechanism was found to be of Fickian type. Conclusion: Ex vivo gut permeation studies revealed 4 times enhancement in the permeation of drug present in the nanocomposite as compared to plain drug solution and were further affirmed by CLSM. Thus, gelatin/(MMT) nanocomposite could be promising for the oral delivery of PTX in cancer therapy and future prospects for the industrial pharmacy.


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