Engineering Development of Therapeutic Systems: A New Class of Dosage Forms for the Controlled Delivery of Drugs

Yates, F. Eugene; Benson, Harriet; Buckles, Richard G.; Urquhart, John; Zaffaroni, Alejandro

doi:10.1016/b978-0-12-004905-9.50006-2

Cited by 17 publications

(13 citation statements)

References 20 publications

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“…However, many variables can influence drug dissolution and absorption in these areas, including rate of gastric emptying, intestinal motility, mass and pH of intestinal contents, and condition of the absorbing surfaces (15)(16)(17). These variables, in turn, can be affected by the patient's disease, posture, and eating habits, and even by such aspects of the treatment as the timing of doses (11).…”

Section: Stomach Small Intestine and Colonmentioning

confidence: 99%

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Controlled Release Technology, Pharmaceutical

Edgren

Leeper

Nichols

et al. 2000

Kirk-Othmer Encyclopedia of Chemical Technology

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Controlled-release dosage forms enhance the safety, efficacy, and reliability of drug therapy. They regulate the drug release rate to control drug action and reduce the frequency of drug administration to encourage patients to comply with dosing instructions. Conventional dosage forms often lead to wide swings in serumdrug concentrations. Most of the drug content is released soon after administration, causing drug levels in the body to rise rapidly, peak, and then decline sharply. For drugs whose actions correlate with their serumdrug concentration, these sharp fluctuations often cause unacceptable side effects at the peaks, followed by inadequate therapy at the troughs (Fig. 1). Administering smaller doses at more frequent intervals can damp concentration fluctuations, preventing over-and underdosing, but the inconvenience may cause patients to skip or delay doses, degrading efficacy. Compliance, measured as the percentage of patients taking 95% to 105% of prescribed oral medications, decreased from 67% with once-a-day regimens to 22% with four-times-a-day regimens (1). These difficulties are especially pronounced with drugs that have short half-lives and a narrow range of safe and effective concentrations. Precisely controlled release is particularly valuable for such agents (see Drug delivery systems).The term controlled release technology generally refers to a variety of methods used to exert various degrees of control over drug release. The U.S. Food and Drug Administration (FDA) defines controlled release dosage forms as those formulations designed to release active ingredient(s) at rates that differ significantly from their corresponding immediate release forms (2). The indexing system of Index Medicus supports this broad definition by classifying these dosage forms as delayed-action preparations, and Excerpta Medica uses the index term sustained release preparations. The pharmaceutical literature contains a profusion of terms, including delayed-action, extended action, gradual release, prolonged release, protracted release, slow release, sustained release, depot, retard, and timed-release dosage forms, all emphasizing an increased duration of action (3).To avoid confusion, several researchers have incorporated therapeutic intention into the definition of controlled release (4-7). Thus, controlled-release pharmaceuticals release drugs in vivo according to a predictable, therapeutically rational, programmed rate to achieve the optimal drug concentration in the minimal time (4). Specification by release rate complements specification by quantity; jointly considered, they fix the duration of drug release. Therefore, the drug's duration of action can become a design property of a controlled release dosage form rather than an inherent pharmacokinetic property of the drug molecule.Under this more precise definition, controlled release drug delivery not only provides a predictable, patterned action, but controls the rate of drug release for a predetermined period. Controlled release systems deliver drugs at a con...

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Section: Stomach Small Intestine and Colonmentioning

confidence: 99%

“…Alternatively, closed-loop systems contain a sensor to monitor drug concentration or to administer drug according to a biological need (11).…”

Section: Figmentioning

confidence: 99%

Controlled Release Technology, Pharmaceutical

Edgren

Leeper

Nichols

et al. 2000

Kirk-Othmer Encyclopedia of Chemical Technology

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“…enhance the therapeutic efficacy of the drug. Focus is always pinned on achieving zeroorder release, which is a prerequisite for ideal drug delivery [1,2].…”

Section: Introductionmentioning

confidence: 99%

Core-in-Cup Tablet Design of Metoprolol Succinate and its Evaluation for Controlled Release

Nagaraju¹,

Meera²,

Kaza³

et al. 2009

CDDT

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The core-in-cup matrix tablets of Metoprolol succinate were prepared by wet granulation technique. Of all the investigated formulations, the optimized formulation of MS-09 followed zero-order kinetics of drug release. Trail on MS-09 was formulated using 7.5% hydrogenated castor-oil (HCO) and 4% of hydroxyl propyl methylcellulose (HPMC K15M) with an objective to achieve a linear release profile for 24 h. There is no initial burst release, with 16.17% of drug released during the first hour and release was extended up to 24 hrs. Study of drug release kinetics was performed by application of dissolution data to various kinetic equations like zero-order; first order, Higuchi and Korsmeyer-Peppas, from R(2) value (0.9975) it was concluded that the drug release followed zero order kinetics with both erosion and diffusion as the release mechanisms.

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“…The invention of Alzet osmotic pumps in the 1970s allowed constant, reproducible, and long-term delivery of drugs, peptides, and antibodies to small laboratory rodents (1, 2). Subcutaneously implanted osmotic pumps reduce animal stress and diminish the risk of infections, compared with repeated acute injections.…”

mentioning

confidence: 99%

Replacement of Osmotic Minipumps to Extend the Intracerebral Infusion time of Compounds into the Mouse Brain

Grathwohl

Jucker

2013

BioTechniques

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Osmotic minipumps represent a convenient and established method for targeted delivery of agents into the brain of small rodents. Agents unable to cross the blood brain barrier can be directly infused into the brain parenchyma or lateral ventricle through implanted cannulas. The small volume of the minipump reservoir typically limits the infusion time to 4-6 weeks. Pump changes with reattachment of a new pump reservoir to the cannula might lead to brain tissue irritation or increased intracranial pressure associated with hydrocephalus. Here, we describe a pump reservoir exchange technique using a Y-shaped connection piece (Y-con) between the infusion cannula and the pump reservoir. This allows repeated replacement of a subcutaneously installed pump reservoir for brain delivery of agents in mice. Experimental evaluation of Y-con pump replacement revealed no signs of tissue irritation or hydrocephalus and allowed extended controlled delivery of infusion agents in the brain.

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Engineering Development of Therapeutic Systems: A New Class of Dosage Forms for the Controlled Delivery of Drugs

Cited by 17 publications

References 20 publications

Controlled Release Technology, Pharmaceutical

Controlled Release Technology, Pharmaceutical

Core-in-Cup Tablet Design of Metoprolol Succinate and its Evaluation for Controlled Release

Replacement of Osmotic Minipumps to Extend the Intracerebral Infusion time of Compounds into the Mouse Brain

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