The manufacturing process of bio-drugs

The manufacture of biopharmaceutical substances : - Most highly regulated and rigorously controlled processes

To gain a manufacturing license, the producer should prove that not

only the product itself is safe and effective, but all aspects of the

proposed manufacturing process comply with the highest quality

standards

The bio-drugs approved for medical use should be produced using

the same process by which it is intended to undertake pre-clinical and clinical trials :

Best manufacturing process (Bioprocess) should be established

The factors affecting the safe manufacture of quality bio-drugs

- Design and layout of the manufacturing facility

- Raw materials utilized in the manufacturing process

- Manufacturing process itself

- Training and commitment of personnel involved

in all aspects of the manufacturing operation

- Existence of a regulatory framework which assures the

establishment and maintenance of the highest quality

standards regarding all aspects of manufacturing

Overview of manufacturing process

Key elements

- Clean room, Equipment, Personnel, Water,

Documentation (Product standards, protocols, guidelines)

Infrastructure of a typical manufacturing facility and some relevant operational issues

Source of biopharmaceuticals

Up-stream and down-stream processing of biopharmaceutical products

Analysis of the final products : Quality control

International Pharmacopoeia

Most important factors that determine the safety and efficacy

- Standard of raw materials used in the manufacturing process

- Standard (specification) to which the final product is produced

Standard processes and guides to good manufacturing practice for medicinal products : Play a central role in establishing criteria which guarantee the consistent production of safe and effective bio-drugs

Most pharmaceutical substances are manufactured to exacting specifications in publications : Pharmacopoeias

- International Pharmacopoeias - US (USP), European Pharma ( Eur. Ph.), Japanese Pharmacopoeia

- Products listed in pharmacopoeias : generic drugs

Martindale

The extra pharmacopoeia

To provide concise, unbiased information regarding bio-drugs of clinical interest, largely summarized from the peer-reviewed literatures : not a book of standards

First edition published by William Martindale in 1883

- The 30th edition in 1993

Contains information on around 5,000 bio-drugs in clinical use: Chemical-based drugs and traditional biological substances like antibiotics, hormones, and blood products

Classified based on similar clinical uses or actions

Information about

- Physio-chemical characteristics

- Absorption and fate

- Uses and appropriate mode of administration

- Adverse/side effects

- Suitable dosage levels

List of the major headings under which various drugs are described in Martindale : Table 3.1

Guides to Good Manufacturing Practice

All aspects of biopharmaceutical manufacture must comply with the most rigorous standards to ensure consistent production of a safe and effective bio-drugs

Principles underlining such standards are summarized in publications which detail Good Manufacturing Practice (GMP)

- EU guide to Good Manufacturing Practice for

Medicinal Products

Biopharmaceutical manufacturers must be familiar with the principles, and are legally obliged to ensure adoption of these principles to their specific manufacturing process

Regulatory authority assesses compliance of the manufacturer with the principles by undertaking regular inspections of the facility

Subsequent granting/renewing (or refusing) of a manufacturing license depends largely on the level of compliance found during the inspection

Principles outlined in GMP

Each chapter is concerned with a specific aspect of pharmaceutical manufacture : Common-sense guidelines

- List of contents in the EU Guide to GMP for Medicinal

products : Table 3.2

GMP in relation to personnel

- Adequate number of sufficiently qualified, experienced personnel

should be employed by the manufacturer

- Key personnel, such as the heads of production and quality control,

must be independent of each other

- Personnel should have well-defined job descriptions, and should

receive adequate training

- Issues of personal hygiene should be emphasized to prevent

product contamination

Principles regarding Premises and equipments

All premises and equipment should be designed, operated, and serviced to carry out their intended functions

Facility and equipment should be designed and used to avoid cross-contamination or mix-up between different products

Sufficient storage area must be provided, and clear demarcation must exist between storage zones for materials at different levels of processing (raw materials, partially processes products, finished products etc..)

Quality control labs must be separated from production, and must be designed to fulfill their intended function

Some of the principles outlined in the guide are sufficiently general to render them applicable to most manufacturing industries

Most of principles outlined in guides to GMP are equally as applicable to the manufacture of traditional pharmaceuticals as to new ones

Many of the guidelines are specific : Guidelines relating to the requirement for dedicated facilities when manufacturing specific products

Manufacturing facility

Appropriate design and layout of the facility : Crucial to the production of safe and effective medicines

Commonly contains :

- Specific production of a target drug

- Quality control, Storage areas, etc

cf) Injectable bio-drugs : Require unique facility design and operation safety of product

- Clean room technology

- Generation of ultra pure water (WFI : water for injection)

- Proper design and maintenance of non-critical

areas : storage, labeling, and packing areas

Clean rooms

Environmentally controlled areas for injectable/sterile biopharmaceutricals : specifically designed to protect the product from contamination (microorganisms and particulate matters etc.)

Designed in a way that allows tight control of entry of all substances and personnel (e.g., equipment, in-process product, air etc..)

A basic feature of design : Installation of high efficiency particulate air (HEPA) filters in the ceilings :

- Layers of high-density glass fiber : Depth filter

- Flow pattern of HEPA-filtered air : Fig. 3.1

- Air is pumped into the room via the filters,

generating a constant downward sweeping motion

Clean rooms with various levels of cleanliness :

- Classified based on the number of airborne particles

and viable microorganisms in the room

- Maximum permitted number of particles or microorganisms per m3 of clean room air

Europe :

5 μm particle dia viable microorganisms

Grade A : 0 < 1

B : 0 5

C : 2,000 100

D : 20,000 500

USA :

class 100 (grade A/B),

class 10,000(grade C),

class 100,000 (grade D)

Factors affecting the clean room condition

Use of HEPA filters with high particulate-removing efficiency

Generation of a unidirectional downward air distribution pattern (i.e. laminar flow)

Additional elements critical to maintaining intended clean room conditions

- All exposed surfaces : a smooth, sealed impervious finish in order to minimize accumulation of dirt/microbial particles to facilitate effective cleaning procedures

- Floors, walls, and ceilings : coated with durable, chemical-resistance

materials like epoxy resins, polyester, PVC coatings

- Fixtures (work benches, chairs, equipments etc..) : designed and fabricated to facilitate cleaning processes

- Air-lock systems : buffer zone

- prevention of contamination

- entry of all substances/personnel into a clean room

must occur via air-lock systems

- An interlocking system : doors are never simultaneously open, precluding formation of a direct corridor between

the uncontrolled area and clean area

Generalized clean room design: Figure 3.2

- Separated entries and exits for personnel, raw materials,

and products

- Personnel represent a major potential source of process contaminants: required to wear specialized protective clothing when working in clean area

- Operators enter the clean area via a separated air-lock

- High standard of personnel hygiene

- Only the minimum number of personnel required should be present in the clean area at any given time

Cleaning, decontamination, and sanitation (CDS)

CDS regime : essential to the production of a safe and effective biopharmaceuticals

- Cleaning : removal of “dirt” (organic/inorganic materials)

- Decontamination : inactivation and removal of undesirable

substances, which generally exhibit some specific biological activity

ex) endotoxins, viruses, prions

- Sanitation : destruction and removal of viable microorganisms

Effective CDS procedures are routinely applied to :

- Surfaces are not direct contact with the product (e.g. clean room

walls and floors)

- Surfaces coming into direct contact with the product (e.g.

manufacturing vessels, product filters, columns)

CDS of process equipment

- surfaces/equipment in direct contact with the product : special

CDS requirement

- no trace of the CDS reagents product contamination

Final stage of CDS procedures involves exhaustive rinsing with

highly pure water (water for injections (WFI))

CDS of processing and holding vessels as well as equipment that is easily detachable/dismantled (e.g., homogenizer, centrifuge rotors etc.,) straightforward

Cleaning in place(CIP) : large equipment/process fixtures due to the impracticality/undesirability of their dismantling

ex) internal surfaces of fermentation equipment, fixed piping, large processing/storage tanks, process-scale chromatographic column

- General procedure: A detergent solution in WFI,

passage of sterilizing live steam generated from WFI

CDS of process-scale chromatography systems :

challenging

ex) Processing of product derived from microbial sources : contamination with lipid, endotoxins, nucleic acids, proteins

Water for biopharmaceutical processing

Water : One of the most important raw materials :

used as a basic ingredient

- Cell culture media, buffers, solvent in extraction and

purification, solvent in preparation of liquid form and

freeze-dried products

- used for ancillary processes : cleaning

- ~ 30,000 liters of water : production of 1 kg of a

recombinant biopharmaceutical produced in a

microbial system

Generation of water of suitable purity : central to

successful operation of facility

Two levels of water quality : purified water and WFI

- Outlined in international pharmacopoeias

Use of purified water:

- Solvent in the manufacture of aqueous-based oral products (e.g., cough mixtures, )

- Primary cleaning of some process equipment/clean room floors in class D or C area,

- Generation of steam in the facilities, autoclaves

- Cell culture media

Water for injection (WFI)

- Highest purity

- Extensive use in biopharmaceutical manufacturing

Generation of purified water and WFI

Generated from potable water

Potential impurities in potable water : Table 3.7

Multi-step purification steps for purified water and WFI:

Monitoring of each step : continuous measurement of the resistivity of the water

ex) Deionization : anion/cation exchangers

Increased resistivity with purity up to 1- 10 MΩ

Filters to remove microorganisms: 0.22 µm, 0,45 µm

Reverse osmosis (RO) membrane : Semi-permeable membrane (permeable to the solvent, water, but impermeable to solute, i.e., contaminants)

General procedure for WFI

Potable water

depth filtration organic trap (resin)

activated charcoal

Anion exchanger Cation exchanger

Deionization step : monitored by measuring the

water resistivity

Filtration with membrane to remove microorganisms

- “purified water”

Distillation (or reverse osmosis)

Water for injection(WFI)

Documentation

Adequate documentation : Essential part of GMP

Essential in order to

- Help prevent errors/misunderstandings associated

with verbal communication

- Facilitate the tracing of the manufacturing history of

any batch of product

- Ensure reproducibility in all aspects of pharmaceutical

manufacture

Categories

Most documents associated with biopharmaceutical manufacturing fall into one of four categories

- Standard operating procedures (SOPs)

- Specifications

- Manufacturing formulae, processing and

packaging instructions

- Records

Documents should be written/worded in a clear and unambiguous fashion by supervisory personnel and inspected by senior technical personnel like production or QC manager before final approval for general use

SOPs (Standard Operating Procedures)

Documents detailing how staff should undertake particular procedures or processes

General categories - SOPs detailing step-by-step operational procedures for specific items

of equipment (e.g., autoclave, homogenizer, freeze-dryers etc.,)

- SOPs detailing maintenance/validation procedures for specific items of equipment or facility areas, e.g., SOPs detailing CDS of clean rooms

- SOPs relating directly to personnel (e.g., step-by-step procedures before entering a clean room)

- SOPs relating to testing/analysis (e.g., QC analysis of final product

how to properly sample raw materials/products, testing of WFI etc.)

Specifications

Exact qualitative and quantitative requirements for raw materials or product

- Specifications for raw material (ex., percentage active

ingredients, permitted levels of impurities)

- Specifications for packing materials (ex., exact dimension

of product packaging, details of product labels etc.)

- Specifications for final product (ex., purity, color,

formulation etc.)

Normally written by QC personnel

Specifications for raw materials / final product : conforming with appropriate pharmacopoeia

Manufacturing formulae, processing and packaging instructions

Provide sufficient information to allow a technically competent person to successfully undertake the manufacturing procedure

Manufacturing formulae - Product name, potency / strength, exact batch size, starting raw

materials, quantity of each material

- Processing instructions :

Principal items of equipment, precise location where each step should be undertaken (e g., in a specific clean room), specific precautions during manufacturing, labeling of each product and packing instructions

A copy of the label to be used is generally attached to the documents

Records

Maintenance of adequate and accurate records

For any given batch of product, records relating to every aspect of manufacture are retained for at least 1 year

Records include:

- Specification results obtained on all raw materials

- Batch manufacturing, processing, and packaging records

- QC analysis results of bulk and finished product

The records should allow tracing back of all manufacturing steps, for the case of any difficulty or problem regarding the production of final product