8/17/2019 Bio Availability Solved Problems

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G.S.N. Koteswara Rao, M.Pharm., D.D.D., D.C.T., (Ph.D), (MBA) Asst. Professor,RAGHU College of Pharmacy,Visakhapatnam. Pharmacokinetics Solved Problems www.raghupharmacy.com  www.pharmainfo.net/og/rcp/downloads 

www.pharmainfo.net/eswar Page 1 of 2 eswar@pharmainfo.net 

PROBLEM-7:

AUC values of penicillin up on i.v administration of 50 mg and oral administration of 100 mg tablet

were found to be 70 and 90 respectively.Calculate:a.  Absolute Bioavailability of penicillin.

b. 

Relatively Bioavailability of penicillin from tablet based on penicillin suspension whose dose is100 mg and AUC is 95.

SOLUTION-7:

a.  Calculate Absolute Bioavailability of penicillin.Given,

i.v. dose of penicillin, Div = 50 mgOral dose of penicillin tablet, Doral = 100 mg

AUC of iv administered penicillin, [AUC]iv = 70 mg. hr/ltAUC of oral administered penicillin, [AUC]oral = 90 mg. hr/lt

Absolute Bioavailability, F = ?Formula:

orali.v

i.voral

D[AUC]

D[AUC] Fility,BioavailabAbsolute   = x 100

F =90 x 50 

=4500

= 0.64 x 100 = 64%70 x 100  7000

b.  Calculate Relatively Bioavailability of penicillin from tablet based on penicillin suspension

whose dose is 100 mg and AUC is 95.

Dose of penicillin tablet, Dtest = 100 mgDose of penicillin suspension, Dstd = 100 mgAUC of penicillin tablet, [AUC]test = 90 mg. hr/lt

AUC of penicillin suspension, [AUC]std = 95 mg. hr/ltRelative Bioavailability, Fr = ?

Formula:

teststd

stdtest

rD[AUC]

D[AUC] Fility,BioavailabAbsolute   = x 100

Fr =90 x 100 

=9000

= 0.95 x 100 = 95%95 x 100  9500

Pharmacokinetics Bioavailability

Solved Problems

by G.S.N.K.Rao {Eswar}

8/17/2019 Bio Availability Solved Problems

2/2

G.S.N. Koteswara Rao, M.Pharm., D.D.D., D.C.T., (Ph.D), (MBA) Asst. Professor,RAGHU College of Pharmacy,Visakhapatnam. Pharmacokinetics Solved Problems www.raghupharmacy.com  www.pharmainfo.net/og/rcp/downloads 

www.pharmainfo.net/eswar Page 2 of 2 eswar@pharmainfo.net 

PROBLEM-8:Following data is obtained for 4 formulations of pentoxyifylline in volunteers of average weight 50 kg.

Drug Product Dose (mg/kg) AUC (mg. hr/lt)

i.v. solution 1.2 450

oral solution 4.0 822

oral capsule 4.0 736

oral S.R. tablet 8.0 1040

SOLUTION-8:

Given data:

Drug Product Dose

(mg/kg)

Dose in

mg /50kg

AUC (mg. hr/lt)

i.v. solution 1.2 Di.v. = 1.2 x 50 = 60 [AUC]i.v. = 450

oral solution 4.0 Dsol

 = 200 [AUC]sol

 = 822

oral capsule 4.0 Dcap = 200 [AUC]cap = 736

oral S.R. tablet 8.0 DSR = 400 [AUC]SR = 1040

a.  What is the absolute bioavailability of the drug from capsule?

F =[AUC]cap Di.v.

=736 x 60 

=44,160

= 0.49 x 00 = 49%[AUC]i.v. Dcap  450 x 200  90,000

b.  What is the absolute bioavailability of the drug from S.R. tablet?

F = [AUC]S.R Di.v. = 1040 x 60  = 62,400 = 0.346 x 00 = 34.6%[AUC]i.v. DS.R.  450 x 400  1,80,000

c.  What is the relative bioavailability of capsule against oral solution?

Fr =[AUC]cap Dsol

=736 x 200 

=1,47,200

= 0.895 x 00 = 89.5%[AUC]sol Dcap  822 x 200  1,64,400

d.  What is the relative bioavailability of S.R. tablet against oral solution?

Fr =[AUC]S.R. Dsol

=1040 x 200 

=2,08,000

= 0.632 x 00 = 63.2%

[AUC]sol DS.R.  822 x 400  3,28,800

e.  Which solid formulation shows better bioavailability?Bioavailability of capsule (49%) is more than S.R. tablet (34.6%).

 Reference: Bio-Pharmaceutics and Pharmacokinetics by: Brahmankar

: V. Venkateswarlu GOOD LUCK