TY - JOUR
T1 - In vitro release of albumin loaded carbonate hydroxyapatite gels
AU - Barralet, Jake
AU - Aldred, S
AU - Wright, Adrian
AU - Coombes, AGA
PY - 2002/6/5
Y1 - 2002/6/5
N2 - Hydroxyapatite (HA) powder, porous HA, plasma-sprayed HA, apatite cements, and sintered HA have all been investigated as delivery systems for compounds such as human growth hormone and vancomycin. However, many previous studies showed that the period of release was limited to 2-3 weeks. The concept of using a nanoporous matrix as a means of immobilizing proteins is well known but has largely been confined to silica-based systems. Carbonate hydroxyapatite (CHA) is more soluble in vivo than HA, and when formed as an aqueous precipitate, it is often formed as nanocrystals. This study investigated the release profiles of ovine albumin (OVA) from CHA gel stored in phosphate-buffered saline (PBS) and double distilled water (DDW) for times of up to 1 year. It was found that 7.9% OVA could be loaded onto apatitic gels by means of a purely aqueous process. This process provided a simple low-temperature method of protein adsorption on a high surface area apatitic matrix at physiological pH. The rate of short-term release of OVA was lower from CHA gels than from microcrystalline HA powder. However, the period of release from the CHA gel was short term and may have been associated with recrystallization of the gel. OVA loaded into CHA gel was found to remain undegraded in vitro at 37degreesC for periods of up to 1 year. (C) 2002 Wiley Periodicals, Inc.
AB - Hydroxyapatite (HA) powder, porous HA, plasma-sprayed HA, apatite cements, and sintered HA have all been investigated as delivery systems for compounds such as human growth hormone and vancomycin. However, many previous studies showed that the period of release was limited to 2-3 weeks. The concept of using a nanoporous matrix as a means of immobilizing proteins is well known but has largely been confined to silica-based systems. Carbonate hydroxyapatite (CHA) is more soluble in vivo than HA, and when formed as an aqueous precipitate, it is often formed as nanocrystals. This study investigated the release profiles of ovine albumin (OVA) from CHA gel stored in phosphate-buffered saline (PBS) and double distilled water (DDW) for times of up to 1 year. It was found that 7.9% OVA could be loaded onto apatitic gels by means of a purely aqueous process. This process provided a simple low-temperature method of protein adsorption on a high surface area apatitic matrix at physiological pH. The rate of short-term release of OVA was lower from CHA gels than from microcrystalline HA powder. However, the period of release from the CHA gel was short term and may have been associated with recrystallization of the gel. OVA loaded into CHA gel was found to remain undegraded in vitro at 37degreesC for periods of up to 1 year. (C) 2002 Wiley Periodicals, Inc.
UR - http://www.scopus.com/inward/record.url?scp=0037024103&partnerID=8YFLogxK
U2 - 10.1002/jbm.10070
DO - 10.1002/jbm.10070
M3 - Article
C2 - 11920658
SN - 0021-9304
VL - 60
SP - 360
EP - 367
JO - Journal of Biomedical Materials Research. Part A
JF - Journal of Biomedical Materials Research. Part A
IS - 3
ER -