Dissolution Rate Studies II

Niebergall, Paul J.; Milosovich, George; Goyan, Jere E.

doi:10.1002/jps.2600520310

Cited by 106 publications

(31 citation statements)

References 6 publications

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“…The fundamental differences between these models rely upon the interdependency between the diffusion layer thickness (h) and particle size (d). Indeed, while some authors, like Hixson and Crowell, 10 for example, assume h to be a constant, others considered h to be proportional to the particle diametersapproximately equal to the particle radius, like Higuchi and Hiestand, 11 or its square root, like Niebergall et al 12 Different algebraic relations between h and d result, obviously, in different equations for the integrated form of eq 1. These equations, together with the associated assumptions regarding the value of h and the corresponding dissolution rate constants are presented in Table 1.…”

Section: Theoreticalmentioning

confidence: 99%

Modeling Dissolution of Sparingly Soluble Multisized Powders

Almeida¹,

Simões²,

Brito

et al. 1997

Journal of Pharmaceutical Sciences

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0 The dissolution of powder drugs, besides being a topic of utmost importance, especially for the sparingly soluble ones, is far from being well-explained. The purpose of the present study is, on the one hand, to obtain experimental dissolution profiles and, on the other hand, to analyze and process the data for dissolution modeling. Three different size fractions of a widely used sparingly soluble drugsibuprofenswere fully characterized with regard to its particle size distribution, specific surface area, density, solubility, and diffusion coefficient. The dissolution profiles were obtained making use of a technique that counts and sizes particlessthe Coulter counter techniqueswhich is capable of following the number and size of the particles in suspension throughout time. The knowledge of these parameters allowed a critical study of the assumptions associated with the models currently used to describe the dissolution process. It was concluded that most of the assumptions were not valid for the present experimental conditions. This motivated the proposal of a new methodology, which uses the experimentally determined characteristics of the drug and takes into account the polydisperse nature of the powder. By applying an adequate dissolution equation to each of the many size classes in which the primary particle size distribution was divided, it was possible to obtain a large agreement between the simulated and the experimental dissolution profile.

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Section: Theoreticalmentioning

confidence: 99%

Modeling Dissolution of Sparingly Soluble Multisized Powders

Almeida¹,

Simões²,

Brito

et al. 1997

Journal of Pharmaceutical Sciences

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show abstract

“…The percentages of drug released from the fibrous web were plotted against time. The drug release studies were carried out on PCL and PCL/PVP blended fibrous mat alone and the kinetics studies were carried out on the drug release from the mat using the Zero order, First order, Higuchi, Hixson-crowell and Peppas model as suggested in the literature [19][20][21][22][23].…”

Section: In Vitro Drug Release Studiesmentioning

confidence: 99%

Centrifugal spun ultrafine fibrous web as a potential drug delivery vehicle

Mary¹,

Thinakaran²,

Suganya³

et al. 2013

Express Polym. Lett.

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Abstract.Centrifugal spinning (C-spin) is one of the emerging techniques for the production of ultrafine fibrous web which mimics Extracellular matrix (ECM). Due to its unique characteristic features it is widely used in bio-medical applications such as tissue engineered scaffolds, wound dressing materials and drug delivery vehicles. In the present study tetracycline loaded polycaprolactone (PCL) blended polyvinyl pyrrolidone (PVP) fibers were fabricated using in-house built C-spin system. The developed ultrafine fibers were morphologically characterized by Scanning Electron Microscope (SEM) before and after drug release and the results showed that the developed webs were highly porous and the pores were evenly distributed. Fourier Transform Infrared (FTIR) spectroscopy results confirmed that the drug was incorporated on the fibers. The antibacterial activity and drug releasing strategy were examined and the results showed that the developed webs can effectively act as a drug delivery vehicle.

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“…The earliest and the simplest of such models was introduced by Hixson and Crowley in 1931 [24], and it is often termed the cube root law. Improvements to the model were proposed by Niebergall et al [25], and Higuchi and Hiestand [26]. The treatments became more elaborate with the studies by Carstensen and Musa [27], and by Brooke [28] [29].…”

mentioning

confidence: 98%

Miniaturization of Powder Dissolution Measurement and Estimation of Particle Size

Avdeef

Tsinman

et al. 2009

Chemistry & Biodiversity

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The objective was to investigate the applicability and limitations of an approach for estimating particle size from powder dissolution measurement using as little as 50 microg of sample in 1 ml of buffer solutions. The powder dissolution profiles of five sparingly-soluble drugs (hydrochlorothiazide, phenazopyridine hydrochloride, 2-naphthoic acid, indomethacin, and dipyridamole) were evaluated with a novel biexponential spherical particle equation and also the Wang-Flanagan spherical particle non-sink equation. The results were compared to particle sizing based on measured specific surface area by the Brunauer-Emmett-Teller (BET) method, and also based on Coulter counting. With the exception of hydrochlorothiazide, the model compounds indicated some agglomeration in the dissolution media. The dry-state specific surface area was larger than expected from either the Coulter method or the powder-dissolution data, especially for phenazopyridine hydrochloride. The particle radii estimated by the powder dissolution method ranged from 10 to 68 microm, with equilibrium solubilities spanning from 5 microg/ml (dipyridamole) to 911 microg/ml (hydrochlorothiazide). Powder dissolution data collected with the miniaturized apparatus can be used to determine particle size, with estimated values agreeing reasonably with those measured by the Coulter counter method.

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Dissolution Rate Studies II

Cited by 106 publications

References 6 publications

Modeling Dissolution of Sparingly Soluble Multisized Powders

Modeling Dissolution of Sparingly Soluble Multisized Powders

Centrifugal spun ultrafine fibrous web as a potential drug delivery vehicle

Miniaturization of Powder Dissolution Measurement and Estimation of Particle Size

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