Handbook of Pharmaceutical Controlled Release Technology

Polyester microspheres are extensively studied for controlled release drug delivery devices, and many models have been developed to describe drug release from the bulk polymer.However, the interaction between drugs and polymers is ignored in most of the existing mathematical models. This paper presents a mechanistic model which captures the interplay between acidic drugs and bioresorbable polyesters. The model considers the autocatalytic effect on polymer degradation arising from carboxylic acid end groups of oligomers and drug molecules. Hence, the enhancing effect of acidic drug on the rate of degradation was fully considered. On the other hand the drug release from polyester microspheres is controlled by drug diffusion from polymer matrix. The drug diffusion coefficient depends strongly on the level of degradation of the polymer. This effect is also included in the model. It is shown that the model can effectively predict experimental data in the literature for both polymer degradation and drug release. Furthermore the model is used to design different systems of microspheres which release drugs with either a zero order profile or burst followed by zero order release profile.

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“…16,17 In this case the initial drug concentration is taken as the solubility of the drug which can be represented as …”

Section: Col=0mentioning

confidence: 99%

A Mechanistic Model for Acidic Drug Release Using Microspheres Made of PLGA 50:50

Sevim

Pan

2016

Mol. Pharmaceutics

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“…an implantable or external pump or biopolymer) and is not dependent on environmental conditions. In contrast, sustained release systems provide prolonged release but the release rate is significantly affected by environmental conditions (76). For the local drug delivery to the inner ear, a variety of strategies exist ranging from intratympanic injections of fluids to the use of pumps, polymers and gels.…”

Section: Drug Application Systemsmentioning

confidence: 99%

“…Of special interest are so-called "smart polymers" that are able to respond to chemical or physical changes of the environment such as pH, temperature, and electric field that may allow them to be incorporated into auto-regulated implantable drug delivery systems. Disadvantages are the limited amounts of drug that can be incorporated in a given application form (76,91,92).…”

Section: Iii) Biodegradable Biopolymersmentioning

confidence: 99%

Local inner-ear drug delivery and pharmacokinetics

Salt

Plontke

2005

Drug Discovery Today

163

123

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SummaryA number of drugs are in widespread clinical use for the treatment of inner ear disorders by applying them directly to the inner ear. Many new substances and drug delivery systems specific to the inner ear are under development, and in some cases are undergoing evaluations in animal experiments and in clinical studies. The pharmacokinetics of drugs in the inner ear, however, is not well defined and the field is plagued by technical problems in obtaining pure samples of the inner ear fluids for analysis. Nevertheless, a basic understanding of the mechanisms of drug dispersal in the inner ear has emerged that facilitates the design and interpretation of future pharmacokinetic studies.

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“…Controlled release (CR) of drugs can be achieved by incorporating them either in dissolved or dispersed form in polymers (Wise, 2000). Depending on the final desired elution profile, these systems can be tailored to deliver the drug at a constant rate, in pulsatile manner, in the form of extended release and in other forms.…”

Section: Importance Of Controlled Drug Elution For Desmentioning

confidence: 99%

Mechanism of controlled release kinetics from medical devices

Raval

Parikh

2010

Braz. J. Chem. Eng.

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-Utilization of biodegradable polymers for controlled drug delivery has gained immense attention in the pharmaceutical and medical device industry to administer various drugs, proteins and other biomolecules both systematically and locally to cure several diseases. The efficacy and toxicity of this local therapeutics depends upon drug release kinetics, which will further decide drug deposition, distribution, and retention at the target site. Drug Eluting Stent (DES) presently possesses clinical importance as an alternative to Coronary Artery Bypass Grafting due to the ease of the procedure and comparable safety and efficacy. Many models have been developed to describe the drug delivery from polymeric carriers based on the different mechanisms which control the release phenomenon from DES. Advanced characterization techniques facilitate an understanding of the complexities behind design and related drug release behavior of drug eluting stents, which aids in the development of improved future drug eluting systems. This review discusses different drug release mechanisms, engineering principles, mathematical models and current trends that are proposed for drug-polymer coated medical devices such as cardiovascular stents and different analytical methods currently utilized to probe diverse characteristics of drug eluting devices.

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Handbook of Pharmaceutical Controlled Release Technology

Cited by 202 publications

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A Mechanistic Model for Acidic Drug Release Using Microspheres Made of PLGA 50:50

A Mechanistic Model for Acidic Drug Release Using Microspheres Made of PLGA 50:50

Local inner-ear drug delivery and pharmacokinetics

Mechanism of controlled release kinetics from medical devices

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