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Biology-Related Homework Help Pharmacology Topic started by: Gmill on Mar 5, 2023



Title: Compartment model
Post by: Gmill on Mar 5, 2023
Literature reports suggest that azatamycin follows a two compartment model in human subjects. After administering a single IV dose (10 mg/kg) in eighteen normal volunteers, the investigators demonstrated that the equation best describing azatamycin kinetics was as follows
Cp = 19 e - 4.8 t + 13 e - 0.15 t
k21 = 2.04 hr-1
What is the hybrid distribution half-life?


Title: Re: Compartment model
Post by: bio_man on Mar 5, 2023
Hello,

\(C_p=19e-4.8t+13e-0.15t\)

\(k_{21}=2.04\ hr^{-1}\)

Is this what the equations look like?


Title: Re: Compartment model
Post by: Gmill on Mar 5, 2023
yes


Title: Re: Compartment model
Post by: bio_man on Mar 5, 2023
I don't think so. :s Are you sure it is not:

\(C_p=19e^{-4.8t}+13e^{-0.15t}\)

??


Title: Re: Compartment model
Post by: bio_man on Mar 5, 2023
The hybrid distribution half-life is a parameter that describes the distribution of a drug between the central and peripheral compartments in a two-compartment model. It is calculated as the ln(2) divided by the sum of the elimination rate constant (k10) and the distribution rate constant (k12).

In this case, the elimination rate constant (k10) is not given, but we can use the given information to calculate k10. From the equation Cp = 19 e^(-4.8t) + 13 e^(-0.15t), we can see that the initial concentration (at t=0) is Cp(0) = 19 + 13 = 32 mg/L. At steady state, the infusion rate (R) equals the elimination rate (k10Cp), so we can set R = k10Cpss, where Cpss is the steady-state concentration. Solving for k10, we get:

k10 = R/Cpss = (10 mg/kg * 70 kg)/(32 mg/L * 1) = 21.875 hr^-1

Now we can calculate the hybrid distribution half-life:

k12 = 2.04 hr^-1
k10 = 21.875 hr^-1

hybrid distribution half-life = ln(2) / (k10 + k12)
= ln(2) / (21.875 + 2.04) hr^-1
= 0.030 hr or 1.8 minutes

Therefore, the hybrid distribution half-life of azatamycin in human subjects after a single IV dose (10 mg/kg) is approximately 1.8 minutes.


Title: Re: Compartment model
Post by: Gmill on Mar 6, 2023
yes it's this
Post Merge: A year ago

Thank you!