One open compartement model

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One open compartement model

• Problems

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Basic Equations
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Basic Equations
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Intravenous bolus administration

• A single iv dose of an antibiotic was given to a
  50 kg woman at a dose level of 20 mg/kg. Urine
  and blood samples were removed periodically and
  assayed for parent drug. The following data were
  obtained

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Penentuan parameter farmakokinetik berdasarkan
data Cp

• Data diolah menurut grafik log Cp vs t
• Diperoleh persamaan garis
• y 0.6956-0.2994 x (r-1.0000)
• Jika log Cp log Co k/2.303 t
• maka - k/2.303 -0.2994 dan k 0.6895/jam,
  t1/2 0.693/k 1.0051 jam Co antilog 0.6956
  4.9614 mg/mL

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Penentuan parameter farmakokinetik berdasarkan
data Du
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• t nilai tengah waktu pengambilan sampel
• ?tinterval waktu pengambilan sampel
• Pers garis
• Grafik antara log Du/?t versus t memberikan
  garis lurus dengan slope -k/2.303
• Persamaan garis log Du/?t vs t
• y 2.8437 0.2952 x (r-0.9997)
• -k/2.303 -0.2952, jadi k 0.6798/jam dan t1/2
  1.0194 jam.
• Du/?t pada t 0 adalah antilog 2.8437
• Du/ ?t 697.7502 mg/jamlog keDoB

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Dengan sigma-minus method (metoda berd jumlah
obat yang akan dieksresikan)

• Data diolah menurut pers

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Homeworks

• Shargel Yu (5th ed), Learning Questions page 69
  70 no 1, 2, 3, 4 and 6

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Intra-venous infusion

• An antibiotic has a volume of distribution of 10
  L and a k of 0.2 hr-1. A steady state plasma conc
  of 10 mg/mL is desired.The infusion rate needed
  to maintain this conc can be determined as
  follows.
• R Css . Vd . K
• R (10 mg/mL)(10.000L)(0.2 hr-1)
• R 20 mg/hr

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• What is the rate of infusion (mL/min) if the
  drug concentration 25 mg/mL

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• 2. A patient receiving IV theophylline (or
  aminophylline) which has a half-life of 6 hours
  (K0.116/hr) and Vd of 30 L (Cl 3.48 L/hr). The
  steady-state plasma conc for a continuous IV
  infusion of 50 mg/hr

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• If we wish to increase the Css to 18 mg/L, we
  would use the same equation to determine K0

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• or with equation