Drug release factors affecting

Shojaei AH, Paulson J, Honary S. Evaluation of poly(acrylic acid-co-ethylhexyl acrylate) films for mucoadhesive transbuccal drug dehvery Factors affecting the force of mucoadhesion. / Control Release. 2000 67(2-3) 223-32. 

Pitt, C. G., Gratzl, M. M., Jeffcoat, A. R., Zweidinger, R., and Schindler, A., Sustained drug delivery systems. II. Factors affecting release rates from poly( e-caprolactone) and related biodegradable polyesters, J. Pharm. Sci.. 68, 1534-1538, 1979. 

Intramuscularly administered products typically form a depot in the muscle mass from which the drug is slowly absorbed. The peak drug concentration is usually seen within 1-2 hours. Factors affecting the drug-release rate from an IM depot include the compactness of the depot (the less compact and more diffuse, the faster the release), the rheology of the product, concentration and particle size of drug in the vehicle, nature of the solvent or vehicle, volume of the injection, tonicity of the product, and physical form of the product. 

Table 10 Factors Affecting the Release of Drugs from...

Wan, L. S. C., and Lai, W. F., Factors Affecting Dmg Release from Drug-Coated Granules Prepared by Fluidized-Bed Coating, Int. J. Pharmaceutics, 72 163-174(1991)... 

C. B. Lalor, G. L. Flynn, and N. Weiner. Formulation factors affecting release of drug from topical formulations. I. Effect of emulsion type upon in vitro delivery of ethyl p-aminobenzoate. J. Pharm. Sci. 83 1525-1528 (1994). 

Kader A, Jalil R. Formulation factors affecting drug release from poly(lactic acid)(PLA) microcapsule tablets. Drug Dev Ind Phann 1999 25(2) 141 151. 

Varma MVS, Kaushal AM, Garg A, Garg S. Factor affecting mechanism and kinetics of drug release from matrix-based oral controlled drug delivery systems. Am J Drug Deliv 2004 2(1 ) 43-67. 

Lapidus, H. and Lordi, N., Some factors affecting the release of a water-soluble drug from a compressed hydrophilic matrix, Journal of Pharmaceutical Sciences, Vol. 55, No. 8, 1966, pp. 840-843. 

Soluble drugs are considered to be released by diffusion through the matrix and poorly soluble drugs are released by erosion of the matrix. Moreover, it is considered that factors affecting swelling and erosion of these polymers may account for differences between in vitro dissolution results and subsequent in vivo performance when hydrophilic matrix tablets are compared [15]. 

Factors Affecting Drug Release from Sustained-Release Film-Coated Pellets Using Acrylic Aqueous Dispersions, 6th International Conference on Pharmaceutical Technology, June, 2, 1992. 

It may be necessary to consider the effect of a boundary layer on the release rate. A boundary layer of appreciable drug concentration on the surface of the device would hinder drug release by diffusion. The effect of the layer is more marked with drugs of low solubility and with microparticles having irregular surfaces. From this simple example, it can be seen that various factors affect the release rate from reservoir microcapsules. 

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