Polymers Blending as Release Modulating Tool in Drug Delivery

Different polymeric materials have been used as drug delivery vehicles for decades. Natural, semisynthetic, and synthetic polymers each have their own specific characteristics and, due to the physicochemical limitations of each polymer, tuning the release rate and targeting the active ingredient to a specific organ or site of action is a complicated task for pharmaceutical scientists. In this regard, polymer blending has been considered as an attractive approach to fabricate novel and unique drug delivery systems with modified physical and/or chemical characteristics. There are three major polymer blending approaches that are used for drug delivery purposes: physical mixtures, core-shell model, and block copolymer model. Each of these types of polymer blends could significantly affect the loading capacities and the kinetics of drug release from the relevant formulations. Drug release from these blended polymers can be tuned through the changes in temperature and pH of the environment, and physiochemical properties of the target organs. Furthermore, the possible molecular interactions among polymers and drug molecules can significantly affect the drug release profile from these blended polymeric micro- and nanocarriers. In this review, first of all, different types of polymers and their various applications in biomedical sciences have been discussed and smart or stimuli responsive polymers are introduced and categorized based on their nature. Then, the purpose of polymer blending in drug delivery systems has been discussed. Different types of polymer blends including physical mixtures, core-shell polymeric carriers, and block copolymers have been summarized with focus on the effect of polymer blending on encapsulated drug release profiles. Finally, the consequence of each blending approach on drug release profile and kinetics of drug release have been mentioned in tabular format.

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Hydrogel-Forming Microneedle Arrays for Sustained and Controlled Ocular Drug Delivery

Journal of Engineering and Science in Medical Diagnostics and Therapy ◽

10.1115/1.4048481 ◽

2020 ◽

Vol 3 (4) ◽

Author(s):

Maher Amer ◽

Roland K. Chen

Keyword(s):

Drug Delivery ◽

Drug Release ◽

Release Kinetics ◽

Therapeutic Index ◽

Ocular Drug Delivery ◽

Release Profile ◽

Drug Release Profile ◽

Sustained Drug Release ◽

Sustained Drug Delivery ◽

Kinetics Of

Abstract Microneedles (MNs) provide a minimally invasive alternative to intravitreal injections and a promising means to sustainable ocular drug delivery. To optimize the sustained drug release profile and to ease the administration of the MN array to the eye, the number of MNs in an MN array and their layout need to be carefully selected. In this study, the drug release kinetics of MN arrays with varying numbers of MNs (8, 12, and 16) is studied over a four-week period. The MN arrays show a much more uniform drug release profile than the single injections. Only the 16-needle MN array fully released all the amount of loaded drug at the end of the 4-week period. Both 8- and 12-needle arrays showed a steady release rate over the 4-week period, which is the longest sustained release duration that has been reported. Zero-order models are created to predict drug release profiles for the three MN arrays. It is estimated that the MN array with 8 needles can deliver the drug for up to 6 weeks. The models can be used to design MN arrays with a given targeted therapeutic index for sustained drug delivery.

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Towards feedback-controlled nanomedicines for smart, adaptive delivery

Experimental Biology and Medicine ◽

10.1177/1535370218800456 ◽

2018 ◽

Vol 244 (4) ◽

pp. 283-293 ◽

Cited By ~ 4

Author(s):

Stephen J. Jones ◽

Annette F. Taylor ◽

Paul A Beales

Keyword(s):

Drug Delivery ◽

Drug Release ◽

Drug Delivery Systems ◽

Delivery Systems ◽

The Body ◽

Living Systems ◽

Prolonged Release ◽

Drug Bioavailability ◽

Drug Release Profile ◽

Chemical Systems

Nanomedicines for controlled drug release provide temporal and spatial regulation of drug bioavailability in the body. The timing of drug release is usually engineered either for slow gradual release over an extended period of time or for rapid release triggered by a specific change in its physicochemical environment. However, between these two extremes, there is the desirable possibility of adaptive nanomedicines that dynamically modulate drug release in tune with its changing environment. Adaptation and response through communication with its environment is a fundamental trait of living systems; therefore, the design of biomimetic nanomedicines through the approaches of bottom-up synthetic biology provides a viable route to this goal. This could enable drug delivery systems to optimize release in synchronicity with the body’s natural biological rhythms and the personalized physiological characteristics of the patient, e.g. their metabolic rate. Living systems achieve this responsiveness through feedback-controlled biochemical processes that regulate their functional outputs. Towards this goal of adaptive drug delivery systems, we review the general benefits of nanomedicine formulations, provide existing examples of experimental nanomedicines that encapsulate the metabolic function of enzymes, and give relevant examples of feedback-controlled chemical systems. These are the underpinning concepts that hold promise to be combined to form novel adaptive release systems. Furthermore, we motivate the advantages of adaptive release through chronobiological examples. By providing a brief review of these topics and an assessment of the state of the art, we aim to provide a useful resource to accelerate developments in this field. Impact statement The timing and rate of release of pharmaceuticals from advanced drug delivery systems is an important property that has received considerable attention in the scientific literature. Broadly, these mostly fall into two classes: controlled release with a prolonged release rate or triggered release where the drug is rapidly released in response to an environmental stimulus. This review aims to highlight the potential for developing adaptive release systems that more subtlety modulate the drug release profile through continuous communication with its environment facilitated through feedback control. By reviewing the key elements of this approach in one place (fundamental principles of nanomedicine, enzymatic nanoreactors for medical therapies and feedback-controlled chemical systems) and providing additional motivating case studies in the context of chronobiology, we hope to inspire innovative development of novel “chrononanomedicines.”

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Ranitidine Loaded Biopolymer Floats: Designing, Characterization, and Evaluation

Journal of Chemistry ◽

10.1155/2017/6924601 ◽

2017 ◽

Vol 2017 ◽

pp. 1-12

Author(s):

Abdul Karim ◽

Muhammad Ashraf Shaheen ◽

Tahir Mehmood ◽

Abdul Rauf Raza ◽

Musadiq Aziz ◽

...

Keyword(s):

Drug Delivery ◽

Drug Release ◽

Lag Time ◽

Zero Order ◽

Release Profile ◽

Drug Release Profile ◽

Independent Variables ◽

Zero Order Kinetics ◽

Model Drug ◽

Predicted Values

The float formulation is a strategy to improve the bioavailability of drugs by gastroretentive drug delivery system (GRDDS). A drug delivery model based on swellable and reswellable low density biopolymers has been designed to evaluate its drug release profile using ranitidine (RNT) as a model drug and formulations have been prepared utilizing 32factorial designs. The drug release (DR) data has been subjected to various kinetic models to investigate the DR mechanism. A reduction in rate has been observed by expanding the amounts of PSG and LSG parts, while an expansion has been noted by increasing the concentration of tragacanth (TG) and citric acid (CA) with an increment in floating time. The stearic acid (SA) has been used to decrease the lag time because a decrease in density of system was observed. The kinetic analysis showed that the optimized formulation (S4F3) followed zero-order kinetics and power law was found to be best fitted due to its minimum lag time and maximum floating ability. The resemblance of observed and predicted values indicated the validity of derived equations for evaluating the effect of independent variables while kinetic study demonstrated that the applied models are feasible for evaluating and developing float for RNT.

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Application of Mathematical Models in Drug Release Kinetics of Cyanocobalamine Fast Dissolving Sublingual Film

Asian Journal of Medicine and Health ◽

10.9734/ajmah/2021/v19i830360 ◽

2021 ◽

pp. 72-81

Author(s):

Adil Patel ◽

Ami Kalsariya ◽

Srushti Patel ◽

Chandni Patel ◽

Shreya Patel

Keyword(s):

Drug Release ◽

Mathematical Models ◽

Release Kinetics ◽

Release Profile ◽

Suitable Model ◽

Order Model ◽

Drug Release Profile ◽

Casting Technique ◽

Kinetics Of

The aim of present work is to determine and analyse the kinetics of drug release from the fast dissolving sublingual by employing various mathematical models. A study was done with Cyanocobalamine fast dissolving sublingual films, 1.5 mg/film by employing solvent casting technique using dehydrated banana starch and Gelatin. The in-vitro drug release profile was carried out in pH 6.8 phosphate buffer (900 mL) using USP dissolution apparatus I (Basket) at 50 rpm for 20 mins. The drug release data was obtained, quantitatively correlated and interpreted with various mathematical models viz. Zero order model, first order model, Higuchi model, Hixson-Crowell model and Korsmeyer-Peppas model and evaluated to understand the kinetics of drug release. The criterion for the most suitable model was based on the high degree of coefficient of correlation of drug release profile of Cyanocobalamine fast dissolving sublingual films.

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Preparation and characterization of azathioprine microspheres for colon specific delivery

Journal of Drug Delivery and Therapeutics ◽

10.22270/jddt.v9i2.2519 ◽

2019 ◽

Vol 9 (2) ◽

pp. 97-101

Author(s):

Rinku Gonekar ◽

Mohan Lal Kori

Keyword(s):

Drug Delivery ◽

Particle Size ◽

Drug Release ◽

Study Drug ◽

Entrapment Efficiency ◽

Release Profile ◽

Intestinal Fluid ◽

Drug Release Profile ◽

Fecal Matter

The objective of the present study is to develop colon targeted drug delivery system using dextrin (polysaccharide) as a carrier for Azathioprine. Microspheres containing azathioprine, dextrin and various excipients were prepared by solvent evaporation technique. The prepared microsphere were evaluated by different methods parameters like particle size, drug entrapment efficiency, percentage yield, shape and surface morphology and in vitro drug release study. Drug release profile was evaluated in simulated gastric, intestinal fluid and simulated colonic fluid. Best formulation was decided on the basis drug release profile in simulated gastric, intestinal fluid and simulated colonic fluid. In dextrin based microspheres, dextrin as a carrier was found to be suitable for targeting of Azathioprine for local action in the site of colon. Dextrin microspheres released 95-99% of azathioprine in simulated colonic fluid with 4% human fecal matter solution. The results of in-vitro studies of the azathioprine microspheres indicate that for colon targeting dextrin are suitable carriers to deliver the drug specifically in the colonic region. Dextrin based azathoprine microspheres showed no significance change in particle size and % residual upon storage at 5 ± 3ºC, 25 ± 2ºC/60 ± 5% RH (room temperature) and 40 ± 2ºC/75 ±5%RH humidity for three months. Keywords: azathioprine, microsphere, dextrin, colon specific drug delivery.

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