4 Formulation of Biotech Products, Including Biopharmaceutical...

By Yuqiong Xia2013-9-30

Formulation of Biotech Products, Including Biopharmaceutical Considerations

Pharmaceutical Biotechnology

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Microbiological considerationsExcipients in parenteral formulations of biotech productsDelivery of proteins: Routes of administration and absorption enhancementDelivery of proteins: approaches for rate-controlled and target site-specific delivery by the parenteral routeApproaches for rate-controlled delivery

生物制药工程夏玉琼西安电子科技大学

Microbiological considerations: 1/3

Sterility Protein assembled in aseptic (无菌)conditions Equipment and excipients are treated separately and

autoclaved （高压灭菌）

Heat or filtration to remove micro bacteria contaminants



Viral Decontamination Test viral contaminants No (unwanted) viral material should be introduced

(blood-derived human serum albumin should be carefully tested)



Pyrogen removal Pyrogen can induce fever Pyrogen could be from bacteria, virus or fungi Baterial pyrogens are endotoxins from G- bacteria


popolysaccharides: baterial pyrogens

Lipid A moiety High, negative electrical charge


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omponents in marketed formulations


olubility enhancers

Proteins have a tendency to aggregateSolubility enhancers Amino acids such as lysine and arginine Surfactants such as SDS

Solubility increase with higher arginine concentration


nti-adsorption and anti-aggregation agents

Adsorption of proteins to interface The interface can be water/air, water/container wall

or water/needle Adsorbed proteins form aggregates and precipitate


nti-adsorption and anti-aggregation agents

The effect of anti-adsorption agents Reduce adsorption of the active protein to interface

Common anti-adsorption agents Albumin (白蛋白) has a strong tendency to adsorb to

surfaces, 1% albumin acts as anti-adhesion agent Surfactant adsorbs to the hydrophobic interfaces and

render this interface hydrophilic 生物制药工程夏玉琼西安电子科技大学

uffer components

Common buffer Phosphate, citrate and acetate

Short, temporary pH change can cause aggregation


reservatives (防腐剂)and antioxidants

Amino acids easy to be oxidized Methionine, cysteine, tryptophan, tyrosine, histidine

Inert gas in the vials can reduce oxidationAntioxidants can also reduce oxidation Ascorbic acid (抗坏血酸，维生素C), acetylcysteine

（乙酰半胱氨酸）生物制药工程夏玉琼

西安电子科技大学

smotic agents

For adjusting the tonicity （渗透压） of parenteral products Saline and mono- or disaccharide solutions are commonly used


reeze-drying

dry dry rehydrate


reeze-drying process and the machine

FreezingThe primary dryingSecondary drying


reeze-drying

Water is removed through sublimation （升华）

Need excipients in freeze-drying Bulking agents Collapse temperature modifier lyoprotectant


reezing

Supercooling and pH change-40 oCEnd when no “free and fluid” water exists

Thrawing/cooling of citric acid-disodium phosphate buffer system


rimary drying

Lowering pressureWater vapor collected on a condenser with lower TShelf heatingEnd when non protein and non-excipient bound water is gone (T d t = T h lf)


econdary drying

Increase T to remove “bound” water

Reduce pressure

20 oC生物制药工程夏玉琼


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arenteral route


ntraperitoneal (IP 腹腔) injections


alf-life of drugs using parenteral route

The half-life of t-PA is a few minutes, while that of mAb is a few days Enhance circulation half-life can be done by switching from IV to IM or IC, however, Enhanced exposure to degradation reactions Differences in deposition


ral route

Patient friendlyLow bioavailability Protein degradation in the gastrointestinal (GI) tract Poor permeability of the wall of the GI tract

Exception: vaccine A small fraction of the antigen has to reach its target

site to elicit an immune response生物制药工程夏玉琼


国家批准的国产口服疫苗


ulmonary（肺的）route


bsorption enhancing effects

Glycocholate (甘胆酸盐)

血糖素

钙素

素

长激素



Starch microsheres



Transdermal iontophoretic delivery 离子电渗疗法


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ndogenous therapeutic proteins

It is important to realize why, when and where they are secreted

内分泌

旁分泌生物制药工程夏玉琼


he necessity of targeted drug delivery

Key issues for therapeutic success of drugs Access to target cells Retention at the target site Proper timing of delivery

For paracrine and autocrine acting proteins, site specific delivery can be highly desirable Cytokines such as tumor necrosis factor and

interleukin-2(白介素) have severe side effects upon


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pproaches for rate-controlled delivery

Polyoxyethylne glycol (PEG) attachment to proteins


ontrolled release systems for parenteral delivery


pen-loop systems: mechanical pumps

Common tools to administrate drugs in hospitalsPulsatile or variable-rate delivery is the desired mode of input for a number of protein drugs, especially insulinProblems Energy failure, problems with syringe, accidental needle

withdrawal, leakage of catheter and problem with injection site

Long-term drug stability The patient has to adapt to the pump rate


pen-loop systems: osmotically driven systems

Semi-permeable membrane

Drug solution leaving via delivery port

Flow moderator

ZA mini-pump


pen-loop systems: osmotically driven systems

Useful when continuous and constant infusion required over long period of timeRelease rated depend on The characteristics of semi-permeable membrane The osmotic pressure difference

Limitation Fixed release rate


pen-loop systems: biodegradable microspheres

PLGA （聚乳酸-聚乙二醇酸） based delivery systems are used extensively E.g. LHRH agonists in the therapy of prostate cancer:

using microspheres, the dosing intervals prolonged from 1~3 months to 6 months



Dextran（葡聚糖）-based microspheres



Dextran-based microspheres

Higher degree of cross-linking,slower rate of release



Critical successful factors The drug has to be highly potent A sustained presence in the body is required No adverse reactions at the injection site


losed loop system

If input rate control is desired to stabilize a certain body function, then this function should be monitored. Via an algorithm（算法） and connected pump settings, this data should be converted into a drug-input rate


losed loop systems: biosensor-pump combinations

If there is a known relationship between plasma level and pharmacological effect, these systems contain A biosensor, measuring the plasma level of the

protein An algorithm, calculating the required input rate A pump system, able to administrate the drug at the

required rate生物制药工程夏玉琼


losed loop systems: biosensor-pump combinations


rotein delivery by self-regulating systems

Drug release is controlled by stimuli in the bodyTwo approaches for controlled drug release Competitive desorption Enzyme-substrate reaction

ulin delivery by competitive desorption

Based on the competition between insulin and glucose for conA

esults of the above insulin delivery

Dogs with pancreatic problems

▲Dogs with pancreatic problems after insulin deliv○Normal dogs

nsulin delivery by Enzyme-substrate reactions

Based on pH drops occurring when glucose is converted to gluconic acid in the presence of the enzyme glucose oxidaseThe pH drop then induces changes in the structure of acid-sensitive delivery devices such as acid sensitive polymers, which start releasing insulin at lower pH

ncapsulated secretory cells

ncapsulated secretory cells

The implanted encapsulated secretory cells should be protected from the body environment Avoid rejection processes Keep the cells from migrating

Thin robust, biocompatible and permselective polymeric membrane have been designed Membrane with a cut off of 50-150 kDa: ensure the

transport of nutrients, but prohibit antibodies

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ite-specific delivery of protein drugs

Why are we still not able to beat cancer? The active compound never reaches the target site Eliminated from body through the kidneys Inactivated through metabolic actions

Only a small fraction of the drug reaches the target site

Many drug molecules do not enter cells easily


Targeted drug delivery should maximize therapeutic effect and avoid toxic effectsRecent progress New drug carriers New insight into pathophysiology of diseases New revelations (揭示) on the nature of anatomical

and physiological carriers


Components for targeted drug delivery

Two types Passive targeting Active targeting

assive targeting

The “natural” disposition pattern of the carrier system is utilized for site-specific deliveryE.g. particulate carriers circulating in the blood are often rapidly taken up by macrophages and accumulate in liver and spleen

ctive targeting

Change the natural disposition of the carrier by some sort of homing device or homing principle to select one particular tissue or cell type

he endothelia barrier

If a drug enters the blood circulation and the target site is outside the blood circulation The drug has to pass through the endothelia barrier

ndothelia cells under pathological conditions

the endothelia cells become leaky under pathological conditions, such as those in tumors and inflammation sites Particles up to 100 nm can enter tumor tissues

Necrotic (坏死的) tissue can also hamper access to tumor tissue

ble carrier systems for targeted delivery of proteins

Antibodies: “natural targeting devices”

Fc can activate complementComplement can cause lysis of target ce

roblems using murine MAb and solutions

Problems Production of human anti-mouse antibodies (HAMA)

Solutions Use of F(ab)2 or F(ab) fragments avoids immune

response against Fc Use human Fc part and murine Fab part Completely human MAb produced by transfecting

human antibody genes into mouse cells

iospecific antibodies

Manufactured from two separate antibodies to create a molecule with two different binding sitesBiospecific MAb bring target cells or tissue (1st

antigen-binding site) in contact with other structures (2nd antigen-binding site)2nd antigen binding site binds to effector cells and trigger cytotoxityE.g. An MAb with carcinoma-surface antigen and an antigen binding site with T-cell affinity

mmunoconjugates

Combinations between an antibody and an active compound

ummary

No bacteria, no virus, no pyrogen in drugsExcipients in parenteral drug deliveryFreeze-drying processControl release of drugsPassive targeting vs active targetingAntibodies with and without drug

omework 4

Please describe the freeze-drying process in your wordsWhich protein do scientists usually use in active targeting?

4 Formulation of Biotech Products, Including Biopharmaceutical...

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