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Title: The studies of drugs release kinetics from hydroxyapatite implants

Abstract:

For a number of drugs their concentration in the site of action (the biophase), determines their therapeutical efficacy. However, in the case of hard tissues owing to their poor and pharmacokinetic properties of a drug, most drugs when administered systemically rarely achieve sufficiently high concentrations in situ. Direct drug delivery into the site of action is an alternative administration route which is an example of targeted drug delivery aiming at assuring optimal drug tissue concentration and at the same time maintaining very low systemic concentration. Biocomposites based on calcium phosphates, and in particular hydroxyapatite ceramics, rank high amongst modem ceramic implants used as bone fillers after removal of defect or dead osseous tissue and may be drug-loaded.The aim of this work was to investigate the kinetics of in vitro and in vivo release of pentoxifylline and ciprofloxacin as model drugs from hydroxyapatite cements of various microstructure and prepared according to different technological procedures, formulated in tablets or hollow cylinders. The goal of the in vitro study was to assess whether the type of biomaterial used, physicochemical properties of a drug and the release medium influenced the drug release mechanism and profile. In vivo test was aimed to determine the serum drug concentration profile after its administration as a drug-loaded implant an ; d evaluate its absolute bioavailability. The results of the research work showed that factors such as hydroxyapatite microstructure, reflected by its porosity which is dependent on the biomaterial composition and preparation procedure, and the method of loading the drug into a matrix (tablets, hollow cylinders), significantly affect drug release profile. Moreover, drug’s solubility and degree of ionization as well as the presence of protein in the matrix are yet another important parameters controlling the rate and amount of released drug. In a heterogenous system (hollow cylinder) drug-release pattern from the tested hydroxyapatite biomaterials generally followed zero-order kinetics, whereas in a homogenous system (tablet) it obeyed Fick’s law of diffusion and followed the Higuchi equation. In conclusion, both in vitro and in vivo petoxifylline release profiles from the tested hydroxyapatite implants appear to be beneficial and suggest that these materials may serve as potential drug delivery systems.

Place of publishing:

Kraków

Level of degree:

2 - studia doktoranckie

Degree discipline:

farmacja

Degree grantor:

Wydział Farmaceutyczny

Promoter:

Szymura-Oleksiak, Joanna

Date issued:

2005

Identifier:

oai:dl.cm-uj.krakow.pl:1231

Call number:

ZB-102287

Language:

pol

Access rights:

tylko w bibliotece

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Last modified:

May 12, 2022

In our library since:

Nov 21, 2012

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http://dl.cm-uj.krakow.pl:8080/publication/1231

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