Pharmacokinetics and pharmacodynamics of biotechnological drugs along with appliations- Proteins and peptides, monoclonal antibodies, oligonucleotides, gene therapy and vaccines

1. Pharmacokinetics and Pharmacodynamics of
Biotechnology Drugs along with its applications
(Proteins and Peptides, Monoclonal antibodies,
Oligonucleotides, Gene therapy, Vaccines)
Presented by,
Snehal R. Tidke
M.Pharm 2nd Semister,
Pharmaceutics Department

2. Biotechnology drugs
The steady advances in cellular biology and
biotechnology have allowed scientist to create new
therapeutic entities mimicing the endogenous bioactive
substances.
These new products include Proteins and
Peptides(PPTs), Monoclonal antibodies(mAbs),
Oligonucleotides, Gene therapy treatment and Vaccines
against microbiological and non microbiological diseases.

3. PROTEINS AND PEPTIDES

4. Proteins and Peptides
Naturally occuring large molecules with secondary or
tertiary structure.
Ensures proper functioning of body's biological events.
Potent, less toxic, binds to their target.
Biotechnologically proteins and peptides are developed
rapidly.
Majority of this drugs are administered parenterally either
by subcutaneous, intramuscular or by systemic
intravenous injection or infusion.

5. P'kinetic and P'dynamic-

6. Absorption
Inhalation administration
Offers ease of administration, provides large surface area
of absortion, bypass first pass metabolism.
Inhaled protein: DNase (pulmozyme)
Enzyme used to break down mucus secretion in
respiratory tracts of patients with cystic fibrosis.
Exubera- systemic form of human insulin to exert
therapeutic effect in inhaled form.
on administration to lungs in dry powder inhaler,
disposition and efficacy were found to be comparable to
those of s.c adm of insulin and absorption was faster.

7. Transdermal administration
Offers advantageous route of bypassing metabolic
degradation and chemical degradation in gastro intestinal
tract and first pass metabolism in liver.
Methods used to Facilitate Transdermal drug delivery
system include sonophorosis and iontophorosis as it
increses skin permeability to ionic compounds.
Ex. Insulin, Interferon-ɣ and Epoetin-α

8. Distribution
Biodistribution studies od PPTs are performed to asses
targeting to specific tissues and to identify major
elimination organs.
The volume if distribution is determined by physio-
chemical properties, protein binding and dependency of
active transport processes.
After i.v application, PPTs usually follow biexpotential
plasma concentration-time profile which is described by
two-compartment p'kinetic model.
Active tissue uptake can increase Vd of PPTs.
Binding to endogeneuos protein structure can influence
the distribution of PPTs.

9. Elimination
 Proteolysis: Proteases and peptidases enzymes are
located within the cells, intracellular uptake is seen more
in elimination rather than distribution process.
Gastrointestinal: Major site of metabolism for orally
administered PPTs. Presystemic metabolism is primarly
seen. Parenterally administered PPTs metabolised in
intestinal mucosa following intestinal secretion.
Hepatic: Proteolysis usually starts with endopeptidases
that attack in middle part of protein and resulting
oligipeptides are then further degraded by exopeptidases.

10. Renal
Mediated through three process of mechanism:
1. Involves glomerular filtration of larger complex proteins
and peptides followed by reabsorption into endocytic
vesicles in proximal tubule and hydrolysis into small
fragment .
2. Glomerular filtration is followed by luminal brush border
membrane of proximal tubules.
3. Peritubular extraction of peptides and proteins from post
glomerulatr capillaries and intracellular metabolism.

11. Examples-
Desmopressin:
Small peptide- 1.18 KDa
Has sufficient bioavailability after intranasal adm to elicit a
systemic therapeutic response.
Used as antidiuretic hormone
Oxytocin:
Peptide with 9 amino acid residues with molecular mass
1.007 KDa.
Given bi i.v infusion
Facilitates childbirth.

12. Antihaemophilic factor:
Large glycoprotein- 320 KDa
produce by recombinant DNA technology.
Elimination half life-14.6 hrs.
Administration- by intravenous infusion.
Used in treatment of haemophilia.

13. As short elimination halt life is recorded in i.v studies, several PPTs are given by
s.c or i.m route rather than i.v as delayed absorption causes plasma drug conc.
to remain high for appreciable period of time as shown below-
DRUG Intravenous
route (in hrs)
Subcutaneous
route (time in
hrs)
Intamuscular
route (time
in hrs)
Treatment
Insulin 0.08-0.12 1.5 - Diabetes
Parathyroid
hormone(forteo)
0.083 1.0 - Osteoporosis
Sargramostim 1.0 2.77 - Mylois stimulation
Engraftment(bone marrow
transplant)
Human growth
harmone
0.33-0.5 3.8 4.9 Growth harmone defciency
Interferon α 5.1 - 7 Chronic hepatitis C

14. The site and mechanism of elimination may be determined
by- charge,oil/water partition coeficient, presence of sugar
or functional group or mol. weight.
ADME differs depending on the size of PPTs as shown in table:
Size of PPTs Molecular weight
(in KDa)
DESCRIPTION
Small proteins <60  Absorption: Proximal tubules (endocytosis)
 lysosomal degradation if complex proteins are present
 metabolised by enzymes in case of v.small linear
peptide ex. bradykinin
Small polypeptide <1 Transportation to hepatocytes for degradation occurs by
• passive diffusion (if lipophilic)
• carrier mediated uptake (if polor)
Moderate size protein 50-200 Receptor mediated endocytosis in liver
Large protein 200-400 In association with immunoglobulins by phagocytosis

15. MONOCLONAL ANTIBODIES

16. Monoclonal antibodies (Ig molecule)
Produced by recombinamt DNA technology
Results in molecules being identical in structure and with
high purity.
Most of the clinically developed or approved mAbs are
administered by intravenous infusion.
Produced sufficiently in large quantities for use as
therapeutic agent.
MAbs are humanised to prevent incidence of
hypersensitivity reaction that can occur from antibodies
from foriegn species.
Bexxar and Zevalin are new class of radioimmunotherapy
drugs use to kill cancer cells.

17. P'kinetic of mAbs
Absorption:
Extra vascular routes have been chosen as alternatives,
including subcutaneous and intramuscular adminstration.
The mAbs enter lymphatic system by convective flow of
interstitial fluid into porous lymphatic vessel and are
further transported unidirectionally into venous system.
 It has been shown that antibodeis can reach systemic
circulation after oral administration, but to very small
extent. The antibodies pass the intestinal epithelium not
by passive transcellular but by receptor mediated
transcellular or paracellular transport.

18. Distribution
Distribution is poor due to high molecular mass and
hydrophilicity/polarity of the molecules.
Transport:
Permeation across cells/tissues is accomplished by
transcellular or paracellular transport, involving process of
diffusuion, convection and cellular uptake. Due to physio-
chemical properties, extent of diffusion across cell
membrane in transcellular transport is minimal.
Endocytosis is absorptive process of large and polar
molecules involving formation of intracellular vesicles from
parts of cell membranes.

19. Elimination
Clearance:
As mAbs do not go glomerulatr filtration due to large size,
tubular sectretion has not been reported to occur to any
significant extebnt for mAbs.
Thus renal elimination is uncommon or low for mAb with
exception for low molecular mass mAbs.
Biliary elimination is has been reported for IgA molecules
and only to very small extent.Therefore, total clearance
(CL) does not comprise renal or biliary clearance.

20. Some of the approved mAb drugs-
DRUG YEAR OF
APPROVAL
ELIMINATION
HALF LIFE
(in hrs)
TARGET APPLICATION
Muromonab 1986 18 CD3 receptor Prevents rejection of
kidney transplant
Abciximab 1994 0.16-0.5
(>10 min)
Inhibits plateplat
aggregation by
targeting
glycoprotein
Prevention of thrombosis
in percutaneuos coronary
intervention
Bevacizumab 2004 20 days Vascular endothelial
groth factor
Colorectal cancer,
Lung cancer,
Metastatic lung cancer

21. Applications
1. Cancer treatment- mAbs against leukemia and
lymphomas have been used in treatment with variable
results.
2. Imaging diagnosis- mAbs is used with radioactive
markers to locate and visualise location and extent of the
tumors.
3. Target specific delivery- mAbs used along with
liposomes. Ex. prokinase congugate with mAbs to
disslove fibrin clots.
4. Transplant rejection suppression- In kidney transplant,
mAbs against CD3 is used.CD3 causes rejection

22. OLIGONUCLEOTIDES
Therapeutic Oliginucleotides are short strands of
nucleotides that interfere with pathogenic proteins.
Oligonucleotides showing activity can serve as basis for
product of MAb or other component that may be eaily
approved for clinical use.
Only two oligoneucleotides have been approved for
clinical use-
1. Fomvirsen - FDA approval in 1998
2. Pegaptanib - FDA approval in 2004

23. PHARMACOKINETICS: Absorption-
Antisense oligonucleotides are majorly administered
parenterally as reported in in-vivo studies: intravenous,
intraperitoneal, or subcutaneuos.
Pharmacokinetics is characterised by-
• A plasma-time profile that is poly phasic with rapid
distribution half life(1hr) and long elimination half-life
reflecting slow elimination from the tissue.
• High binding to plasma proteins (>90% across species).
• Plasma clearance that is dominated by distribution into
tissues.
• Minor urinary or fecal excretion of the intact drug.

24. Distribution:
Highest conc. of oligonucleotides were found in kidney,
liver, spleen and lymph nodes, but can be measured in
almost every tissue except brain at 24hr after IV
adminstration.
Elimination:
While distribution of tissues relies on mechanism of
plasma clearance, whole body clearance is result of
metabolism and excreation of low molecular weight
oligonucleotides.
Tissue metabolism is slow and continuous process and
represent primary route of whole body elimination as
oligonucleotide fragments are excreted from body in

25. Pharmacodynamics
The mechanism of action of antisense compound is to
inhibit the gene expession sequence specifically by the
hybridization to mRNA through Watson-Crick base pair
interactions.
This is followed by the degradation of the target nRNA
through RNase H-dependent terminating mechanism.

26. Examples:
FOMVIRSEN
It represents original type of therapeutic oligonucleutide
which is a antisense compound.
Interferes with mRNA sequence in human.
Inhibits production of some viral proteins essential for viral
replication
Used in local treatment of cytomegalovirus retinitis.
Available in market as Vitravene.

27. PEGAPTANIB
It is an antagonist to endothelial growth factor.
It binds with high affinity to target molecule and
inactivates them.
Use in treatment of neovascular disease which is age
related macular degeneration.
Available in market as Macugen.
GENASENSE
Currently under phase III clinical trial.
Inhibits production of BCL-2 protein.
 Produced by cancer cell.

28. Applications
Antisence oligonucleotides are used to reduce levels of
protein synthesis by inhibiting mRNA processing or
translation.
It is used in treatment of cancer, cytomegalovirus retinitis
and familial hyperholesterolemia.
Common applications are aptamer design, Allel-specific
testing and triplex-forming oligonucleotides for dsDNA
binding.
Aptamers are used as sensors of cellular processes and
therapeutic tools. Aptamers that bind to cell surface
proteins can be use as drug delivery.

29. GENE THERAPY
It is an experimental technique
that uses genes to treat or
prevent diseases.
It is use to replace, manipulate
non-functional or malfunctional
gene with healthy gene.
Vector is used as carrier.
Virus is commonly used vector
which is genetically altered to
carry normal human DNA.

30. Retrovirus:
• Create dsDNA copies of their RNA genomes. This copies
of dsDNA is integrated into chromosome of host cell.
• Ex. HIV virus
Adenovirus:
• Virus with dsDNA genome causes respitaory, intestinal
and eye infections.
• Ex. Virus causing commom cold.
Herpes simplex virus:
• dsDNA infect a particular cell type, neurons. HSV-I is
common human pathogen causing cold sores.

31. Working of gene therapy
Gene to be inserted is genetically modified/ engineered
using vector called as virus (Adenovirus, retrovirus or
herpes simplex virus).
Virus is injected intravenously into specific tissue and
taken up by individual cells. This is in-vivo method.
The sample of a patient's tissue or cell is removed and
exposed to a vector in laboratory. Cells containing vector
is returned to patient's body. This method is called in-vitro
technique.

32. Application
Gene therapy is used to treat diseases with severe
combined immune deficiency, familial
hypercholesterolemia, cystic fibrosis, gausher's diseases.
Some protocols are aimed towards treating of-
• Cancer.
• Alzeimer's disease.
• Parkinson's diseases.
• Arthritis.
• Heart diseases.

33. References-
1. Shargel Leon, Yu.B.C Andrew, Shargel & Yu's,”Applied
Biopharmaceutics and Pharmacokinetics”, Seventh
Edition, Mc Graw Hill Education, Pg no. 618-625.
2. Breen Philip J., Jambhekar Sunil S.,”Basic
Pharmacokinetics”, Second Edition, Pharmaceutical
Press.
3. http://ghr.nlm.nih.gov/

34. Thank you!!