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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2008-10-14
pubmed:abstractText
1. PHA-794428 is a PEGylated version of somatropin (human growth hormone). The pharmacokinetics of PHA-794428 have been studied in humans following single subcutaneous administration (dose range 10-500 microg kg(-1)). In the same study the pharmacokinetics of somatropin were also determined following a 3.6 mg (51 microg kg(-1)) subcutaneous dose. Comparison of the pharmacokinetics of both molecules indicates that PEGylation of somatropin with a 40 kD PEG results in a ten- to 20-fold increase in area under the curve and a similar increase in half-life when compared with somatropin in human (at equivalent subcutaneous doses). 2. Literature data indicate that somotropin is cleared by two mechanisms. The first processes is clearance by glomerular filtration. This is a passive, non-capacity-limited process. A second, capacity-limited, process is mediated by interaction with growth hormone receptors present in a number of tissues including the liver. It is hypothesized that PHA-794428 shares the same clearance mechanisms. However, the addition of the PEG moiety has modulated the clearance by both of these processes. Pharmacokinetic modelling of human serum concentration data obtained for these molecules strongly supports this hypothesis. The renal clearance is reduced due to the increased size of the molecule (Cl/F reduced from 9.6 to 0.1 l h(-1) for somatropin and PHA-794428, respectively). In addition, the reduction in growth hormone receptor affinity has reduced the clearance mediated by interaction with this receptor (somatropin Km = 3.6 microg l(-1) and Vmax = 104 microg h(-1)/PHA-794428 Km = 53 microg l(-1) and Vmax = 84 microg h(-1)).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1366-5928
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
38
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1340-51
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
PEGylation of somatropin (recombinant human growth hormone): impact on its clearance in humans.
pubmed:affiliation
Department of Pharmacokinetics, Pfizer Global Research and Development, Sandwich, UK. Rob.Webster@Pfizers.com
pubmed:publicationType
Journal Article