renal Clearance in Biopharamceutics

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2. Prepared By:-
Ravi Raj Sharma
B.Pharm, GMCTHRC,Pokhara
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3. CONTENTS
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About Renal Clearance
Mechanism of Renal Clearance
Comparison of drug excretion methods
Determination of Renal Clearance
Factors Affecting Renal Clearance
Conclusion
References

4. RENAL CLEARANCE
 Volume of plasma that is cleared of drug per unit
of time through the kidney.
 Constant fraction of VD in which the drug is contained
that is excreted by the kidney per unit of time.
 Mathematically,
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5. RENAL CLEARANCE
Contd…
 Consider the mass balance of drug cleared by the kidney
and ultimately excreted in urine.
 Rate of drug passing through kidney = rate of drug
excreted in urine
= renal clearance = plasma drug concentration
= rate of urine flow = urine drug concentration
excretion rate
=
Cp
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7. COMPARISON OF DRUG EXCRETION METHODS
 ClR = Rate of (filtration + secretion – reabsorption)
Plasma drug concentration.
 Renal clearance ratio = ClR of drug
ClR of creatinine.
 Actual clearance is not obtained by direct measurement.
 Compared to that of standard reference standard such as insulin.
 Clearance ratio indication for the mechanism of renal excretion
of the drug.
14
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8. 16
DETERMINATIONOF RENAL CLEARANCE
First one is Described as it is important in Biopharmaceutics
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9. GRAPHICAL METHODS
 Slope of the curve obtained by plotting rate of drug
excretionin urine (dDu/dt) against Cp.
 For a drug that is excreted rapidly, dDu/dt is large,
the slope is steeper, and clearance is greater.
 For a drug that is excreted slowly through the kidney ,
the slope is smaller.
 Clr = Urinary drug excretion rate dDu/dt
Plasma drug concentration Cp
17
=
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10. GRAPHICAL METHODS
slope = renal clearanceRate of drug
excretion
Plasma level(Cp)
A
B
18
Contd…
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11. GRAPHICAL METHODS
Multiplying both sides by Cp gives
By rearranging and integrating
19
Contd…
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12. GRAPHICAL METHODS
Slope= ClR
Drug excreted in
urine(Du)
Slope= ClR
20
Contd…
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13. FACTORS AFFECTING RENAL CLEARANCE
Physicochemical properties of drug
 Plasma concentration of drug
 Distribution and binding characteristics of drug
 Urine pH
 Blood flow to the kidney
 Biological factors
 Drug interactions
 Disease state
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14. CONCLUSION
 The clearance concept was first introduced to describe renal
excretion of endogenous compounds in order to measure the
kidney function.
 The term is now applied to all organs involved in drug
elimination like liver, lungs, biliary system etc.
 Clearance values gives useful estimates regarding a lot of
disease states. 33
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15. REFERENCES
 Brahmankar DM , Jaiswal Sunil B . Biopharmaceutics and
pharmacokinetics: A TREATISE. 3rd edition(2015)/(Reprint 2016). p.206-
10.
 https://www.sciencedirect.com/topics/medicine-and-dentistry/renal-
clearance
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