Protein and peptide DDS are novel systems of drug delivery. The successful delivery of peptide and protein-based pharmaceuticals is primarily determined by its ability to cross the various barriers presented to it in the biological milieu. Various barriers encountered are- 1 Physiological Barrier 2 Intestinal Epithelial barriers 3 Capillary Endothelial Barrier 4 Blood-Brain barrier (BBB)

1. PROTEIN AND PEPTIDE
DRUG DELIVERY SYSTEM
BPresented by – Jaskiran Kaur
Gui

2. CONTENTS
 Introduction
 Why do we need protein and peptide drugs?
 Advantages of protein and peptide drug delivery system
 Delivery challenges
 Delivery routes of proteins and peptides drugs.
 Barriers to the delivery
 Some marketed formulations

3. INTRODUCTION
 The Protein and Peptide is a Novel approach to Drug
Delivery System .
 Proteins are the high molecular weight mixed polymer
of Alpha amino acids joined together the Peptide
Linkages.
 Protein and Peptides are the Most Abundant Material
of Living system and Biological cell.
 Its act has Hormones, Enzymes, Structural Elements
and Immunoglobulins.
 The discovery of Numerous Hormones and Peptides
are Applicable for the Pharmaceutical and
Biopharmaceuticals.
 First marketed protein – recombinant human insulin in
1982

4. ( Basic unit ) (Amino Acid <=50) (Amino Acid >50)

5. Basic structure of a
protein
Basic structure of a protein
includes:
1. Primary
2. Secondary
3. Tertiary (3D)
4. Quaternary

6. Why do we need protein and peptide drugs?
• Protein and peptide drugs (PPDs) have a great potential as therapeutic agents
because they have higher efficacy and lower toxicity, compared to chemical drugs
• Due to rapid progress in biotechnology, as well as gene technology, production of
potential therapeutic peptides and proteins in commercial quantities possible.
• Therapeutic proteins have increased dramatically in number and frequency of use
since the introduction of first recombinant protein viz, human insulin, 25 years
ago.
• Recent advancements in the proteomics and recombinant DNA technology,
making it feasible to introduce specific functionalities in protein/peptide structure,
has made it possible to synthesize high quality protein– and peptide–drug
conjugates though a wide variety of coupling techniques.
• Additionally, use of specialized linkers makes them unique in their in vivo
therapeutic application by providing target tissue-specific release of drug.

7. ADVANTAGES
 The mode of delivery is convenient, i.e., eye drops.
 Systemic absorption is extremely rapid.
 Avoid first-pass metabolism.
 The formulation can be designed to prolong drug action and/or reduce drug
concentrations to achieve consistent drug action with least side effects.
 The drug delivery can be controlled precisely .
 Protein and peptide drugs (PPDs) have a great potential as therapeutic
agents because they have higher efficacy and lower toxicity, compared to
chemical drugs.
 Enzymatic catalysis in biochemical reactions .

8. DELIVERY CHALLENGES
 Low permeability due to large molecular size(capillary pore size -5 to 12 nm)
 Susceptibility to enzyme degradation
 Short plasma half life
 Immunogenicity
 Aggregation
 Denaturation
 Protein binding

9. DELIVERY ROUTES OF PROTEIN AND PEPTIDE
DRUGS
Different routes incudes:
1. Oral route
2. Buccal route
3. Nasal route
4. Transdermal route
5. Pulmonary route
6. Rectal route
7. Parenteral route

11. BARRIERS TO PROTEIN DRUG DELIVERY
The successful delivery of peptide and protein based pharmaceuticals is
primarily determined by its ability to cross the various barriers presented
to it in the biological milieu. Various barriers encountered are-
 Physiological Barriers
 Intestinal Epithelial barriers
 Capillary Endothelial Barrier
 Blood Brain barrier (BBB)

12. PHYSIOLOGICAL
BARRIERS
Enzymatic barrier
pH gradient
Mucus
Inter-individual
variability

13. Enzymatic Barriers
• PPs are highly susceptible to various proteolytic enzymes including luminal
enzymes from gastrointestinal and pancreatic secretions, bacterial enzymes in the
colon and mucosal enzymes
• They are primarily degraded by luminal enzymes before penetration across mucus.
The entry of the protein could stimulate the gastric mucosa to secret pepsins by the
cells lining the stomach.
• Pepsin is able to degrade proteins into smaller fragments of peptides by
hydrolyzing the peptide bonds
• proteolytic enzymes in the upper part of the small intestine are secreted by
pancreas, such as trypsin, chymotrypsin, carboxypeptidase and elastase
• Most degradation data of PPs were obtained by in vitro simulated gastric or
intestinal fluids with specific enzymes.

14. pH Gradient
• The GI pH is absolutely different in each region of GI tract and influenced by
various factors including presence of food, pathological conditions, even age and
gender.
• Generally, in the healthy adult, the pH of gastric fluids is acidic (pH 1.5–3.5), and
rises to around pH 5–6 in the duodenum due to neutralization of carbonate and
bile juices, and then increases to pH 7–8 in the distal jejunum and ileum, while the
colonic pH could be more than 8 .
• The complicated pH environments in GI tract could lead to conformational
alteration or enzymatic degradation of PPs, resulting in the loss of therapeutic
efficacy.
• The extreme pHs could result in unfolding due to increase of electrostatic
repulsions. Generally, proteins are stable in a narrow pH range which is not far
away from their pI. Thus, some proteins could be inactive in gastric fluids due to
pH induced unfolding.

15. Mucus
• Mucus is a sticky and viscoelastic gel layer covering the entire GI tract. It is
secreted by the goblet cells. Mucus can capture the foreign moieties and protect
epithelia from the attack of exogenous pathogens.
• What's more, there is a pH gradient across whole mucus layer, especially gastric
mucosa. The gastric mucus pH on the luminal surface is about.
• The mucus exerts multiple barriers against the transport of drugs into the
submucosal tissue.
• The high viscosity decreases the diffusivity of PPs through mucus, which directly
affects the residence time of PPs in the small intestine. In the intestine, the average
mucus turnover time is around 50–270 min resulting in the removal of trapped
particles in the mucus layer thereby, limiting the adhesion and holding time of the
particles or PPs.
• The continuous secretion and replacement of mucus make it quite challenging for
the PPs passing through the unstirred mucous layer by infiltration before reaching
the surface of the epithelium.

16. Inter-individual variability
• The tremendous inter-individual variability is also a barrier to limit the
development of PPs.
• For oral delivery, the inter-individual variability in the physiology of GI tract
has significantly affected the bioavailability of oral PPs, such as the condition
of mucus, the secretion of enzymes and gut motility.
• Especially in some disease states, the inter-individual variability is more
evident.
• For example, gastric emptying and oesophageal motility have shown large
variability in type 2 diabetic patients with different stages. The variability in
gut mobility could be particularly relevant to the difference in absorption rate
of PPs.
• Moreover, the pH and the expression of digestive enzymes in GI tract vary
with individuals significantly, which leads to the inter-individual variability of
degradation of PPs in GI tract.

17. Epithelial barriers
• The epithelial cells lying beneath the mucus also act as another
predominant restrictions towards oral protein drug delivery.
• The intestinal epithelia include various types of cells with specific functions,
such as enterocytes for absorption, goblet cells for secretion of mucus,
paneth cells for secretion of enzymes and M cells for transporting foreign
particles.
• The enterocytes are the major absorptive cells and also comprise around
90% of intestinal epithelium
• M cells are the most important epithelial cell types involved in the uptake
and transport of a wide variety of particulates including intestinal antigens
and large proteins, and thus recognized as immune cells of intestinal lumen.

18. • The intestinal absorption of drugs is primarily dependent on transcellular
pathway, while paracellular pathway is the main route of some small
hydrophilic molecules.
• According to Lipinksi “Rule of 5”, PPs are predicted to be extremely low
transcellular permeability because molecular weight is far more than
500 Da.
• Thus, PPs are hard to be absorbed into portal vein by transcellular pathway.
• Moreover, the paracellular route refers to the passage of drugs through
water-filled pores of TJs, the pore sizes of which usually range between 3
and 10 Å
• The molecules larger than 500 Da are generally not recognized to be able to
move through these small pores. TJs can be regulated by some permeation
enhancers, which makes pores larger.

19. Capillary endothelial barriers
• Endothelial cell layers of blood and lymphatic capillaries define the separation
between the blood or lymph fluids in our body and the parenchymal tissues they
supply and void.
• As such, they constitute a phenomenal barrier to the free diffusion of fluids, and
of small and large molecules, as well as of cells of the immune system.
• The capillary endothelium has a average pore size of 6.5 nm and is freely
permeable to small molecules and electrolytes, but not to large protein molecules.
• Plasma proteins, especially albumin, are largely confined to the intravascular
compartment and exert a colloid osmotic pressure (COP) of about 25 mmHg or
1.2 mosmol/kg.

20. Blood Brain Barrier
• Peptide and protein (P/P) drugs have been identified
as showing great promises for the treatment of
various neurodegenerative diseases.
• A major challenge in this regard, however, is the
delivery of P/P drugs over the blood–brain barrier
(BBB).
• Intense research over the last 25 years has enabled
a better understanding of the cellular and molecular
transport mechanisms at the BBB, and several
strategies for enhanced P/P drug delivery over the
BBB have been developed and tested in preclinical
and clinical– experimental research.
• Among them, technology-based approaches
(comprising functionalized nanocarriers and
liposomes) and pharmacological strategies (such as
the use of carrier systems and chimeric peptide
technology) appear to be the most promising ones.

21. • Accordingly, peptides and proteins have become important targets in
neuropharmaceutical drug design for the treatment of a wide variety of CNS
disorders such as ischemia, inflammatory CNS diseases, neurodegenerative
diseases, and acute and chronic pain syndromes.
• However, in spite of their potential, many existing peptide and protein drugs (P/P
drugs) are rendered ineffective in the treatment of these clinical problems due to
the inability to effectively deliver and sustain them within the brain.
• The major obstacle to targeting the brain with therapeutics in general (P/P drugs
amongst them) is the presence of various barriers, in the first line the blood–brain
barrier (BBB), which controls the concentration and entry of solutes into the CNS.
• As understanding of structure and function of the BBB expanded, it became
apparent that many P/P drugs cross the BBB in amounts that are known to affect
the functions of the CNS .
• Successful permeability has been described with reference to various small
(mostly lipophilic) P/P drugs following intraventricular administration

22. • . In addition, it has been widely quoted, that in order for a P/P drug to
cross the BBB in pharmacologically significant amounts, the molecule
must have a molecular weight bellow a threshold of 400–500 Da
(Pardridge, 1998b; Misra et al., 2003; Pavan et al., 2008).
• This molecular weight cutoff value for zero or limited brain
permeability appears to have been based on the studies including a
small portion of CNS proteins with molecular weight greater than 400
Da.
• The tight junction is composed of at least two functionally distinct
pathways: a high-capacity, charge-selective pore pathway that allows
passage of small ions and uncharged molecules and a low-capacity
leak pathway that allows flux of larger ions and molecules, regardless
of charge

25. APPLICATIONS
 CVS acting drugs Protein and Peptides: (Angiotensin 2 antagonist, Bradykinin)
Lowering blood pressure and improving peripheral circulation for Heart failure
management.
 CNS active Protein and Peptides: (Cholecystokinin, Β-endorphin) Suppressing
appetite and Relieving pain.
 GI-active Protein and Peptides: (Gastrin antagonist, pancreatic enzymes) Reducing
secretion of gastric acid and it is important for Digestive supplement.
 Immunomodulation of the Protein and Peptides :(Bursin, Cyclosporin, and
Interferon) Selective B-cell differentiating hormone Inhibits functions of T-
lymphocyte Enhancing activity of killer cells.
 Metabolism modulating Protein and Peptides :(Insulin, Vasopressin) is important for
treating diabetes mellitus and treating diabetes insipidus.

27. Some other marketed formulations

28. THANK YOU