Monday, May 11, 2009

Pharmaceutical Manufacturing

Pharmaceutical Manufacturing

Industry Description and Practices
The pharmaceutical industry includes the manufacture, extraction, processing, purification, and packaging of chemical materials to be used as medication for humans or animals. Pharmaceutical manufacturing is divided into two major stages. The first stage, which is typically referred to as primary processing or manufacture, is the production of the active ingredient or drug. The second stage, secondary processing, is the conversion of the active drugs into products suitable for administration. This document addresses the synthesis of the active ingredients and their usage in the drug formulations to deliver the prescribed dosage. Formulation is also referred to as galenical production. Major pharmaceutical groups manufactured include:

proprietary ethical products or prescription only medicines (POM) and usually are patented products;

general ethical products which are basically standard prescription only medicines made to a recognized formula, which may be specified in standard industry reference books; and

over-the counter (OTC) or non-prescription products. The products are available as tablets; capsules; liquids (which may be in the form of solutions, suspensions, emulsions, gels, or injectables); creams and ointments (which usually consist of an oil-in-water emulsion (cream) or water-in-oil emulsion (ointment)); and aerosols (which contain inhalable products or products suitable for external use).
Propellants used in aerosols include chlorofluorocarbons—CFCs—(which are being phased out) and more recently butane has been used in externally applied products. Major manufactured groups include: (a) antibiotics (such as penicillin, streptomycin, tetracyclines, chloramphenicol, and antifungals); (b) other synthetic drugs including sulfa drugs, anti-tuberculosis drugs, antileprotic drugs, analgesics, anaesthetics, and antimalarials; (c) vitamins; (d) synthetic hormones; (e) glandular products; (f) drugs of vegetable origin such as quinine, strychnine and brucine, emetine, and
glycosides:; (g) vaccines and sera; (h) other pharmaceutical chemicals such as calcium gluconate, ferrous salts, nikethamide, glycerophosphates, chloral hydrate, saccharine, antihistamines ( including meclozine, and buclozine), tranquilizers (including meprobamate and chloropromoazine), antifilarials, diethyl carbamazine citrate, and oral antidiabetics (including tolbutamide and chloropropamide); and (i) surgical sutures and dressings. The principal manufacturing steps are: (a) preparation of process intermediates; (b) introduction of functional groups; (c) coupling and esterification; (d) separation processes (such as washing and stripping); and (e) purification of the final product. In addition, other product preparation steps include granulation; drying; tablet pressing, printing, and coating; filling; and packaging. Each of these steps may generate air emissions, liquid effluents, and solid wastes. The manufacture of penicillin, for example, involves the batch fermentation—100 to 200 cubic meter (m
) batches—of maize steep liquor
or a similar base with organic precursors added to control the yield. Specific mold culture such as
Penicillium chrysogenum
for Type II is inoculated to the fermentation medium. Separation of penicillin from fermentation broth is accomplished using solvent extraction and the product is further purified using acidic extraction. This is followed by treatment with pyrogen-free distilled water solution containing the alkaline salt of the desired element. The purified aqueous concentrate is separated from the solvent in a supercentrifuge and then pressurized through a biological filter to remove the final traces of bacteria and pyrogens. The solution can be concentrated by freeze drying or vacuum spray drying. The oil-soluble procaine penicillin is made by reacting a penicillin concentrate (20 to 30 percent) with a 50 percent aqueous solution of procaine hydrochloride. Procaine penicillin crystallizes from this mixture. The manufacture of pharmaceuticals is controlled by Good Management Practices (GMP) in some countries (for example, refer to Her Majesty's Inspectorate of Pollution, 1993) and some countries require an environmental assessment (EA) report addressing the fate and toxicity of drugs and their metabolized by-products. The EA data relate to the parent drug, not all metabolites, and includes: (a) physical and chemical properties; (b) biodegradability; (c) photolysis propensity; (d) aqueous toxicity to fish; (e) prediction of existing or planned treatment plant to treat wastes and wastewaters; and (f) treatment sequences that are capable of treating wastes and wastewaters.
Waste Characteristics
The principal air pollutants are volatile organic compounds (VOCs) and particulate matter (PM). Liquid effluents resulting from equipment cleaning after batch operation contain toxic organic residues and are variable in their composition depending on the product manufactured, materials used in the process, and other process details. Cooling waters are normally recirculated. Some wastewaters may contain mercury—0.1 to 4 milligrams per liter (mg/L), cadmium (10-600 mg/L), isomers of
hexachlorocyclohexane, 1,2-dichloroethane, and solvents. Typically 25 kilograms kg of biochemical oxygen demand (BOD

per metric ton of product (kg/t) (or 2000 mg/L); 50 kg chemical oxygen demand (COD) per metric ton of products (or 4,000 mg/L), together with 3 kg of suspended solids per metric ton, and up to 0.8 kg of phenol per metric ton are released with the wastewater. However, in some cases, BOD is not to be considered when the pollutants are toxic to the micro-organisms in the test. Major solid wastes of concern include process and effluent treatment sludges, spent catalysts, and container residues. Approximately 200 kg of waste is generated per metric ton of active ingredient manufactured. Some solid wastes contain spent solvents and other toxic organics at significant concentrations.
Pollution Prevention and Control
Every effort should be made to substitute highly toxic and persistent ingredients with degradable and less toxic ones. Recommended pollution prevention measures are to:

Meter and control the quantities of active ingredients to minimize wastage.

Reuse by-products from the process as raw materials or as raw material substitutes in other processes.

Recover solvents used in the process by distillation or other methods.

Give preference to the use of non-halogenated solvents.

Use automated filling to minimize spillage.

Use “closed” feed systems into batch reactors.

Use equipment washdown waters and other process waters (such as leakages from pump seals) as make-up solutions for subsequent batches.

Recirculate cooling water.

Use dedicated dust collectors to recycle recovered materials.

Vent equipment through a vapor recovery system.
• •
Return toxic materials packaging to the supplier for reuse or incinerate/destroy in an environmentally acceptable manner.
Air Emissions

Minimize storage time of off-specification products through regular reprocessing. Stack gas scrubbing, carbon adsorption, (for toxic organics), and baghouses (for particulate matter removal) are applicable and effective technologies for minimizing the release of significant pollutants to air. In some cases, biological filters are also used to reduce emissions of organics. Combustion is used for the destruction of toxic organics.

Find productive uses for off-specification products to avoid disposal problems.

Minimize raw material and product inventory to avoid degradation and wastage.

Use high pressure hoses for equipment cleaning to reduce wastewater.

Provide storm water drainage and avoid its contamination from process areas.
Liquid Effluents

Label and store toxic and hazardous materials in secure bunded areas. Spillage should be collected and re-used. Reverse osmosis or ultra-filtration is used to recover and concentrate active ingredients. Effluent treatment normally includes neutralization, flocculation, flotation, coagulation, filtration, settling, ion exchange, carbon adsorption, detoxification of active ingredients by oxidation (using ozone wet air oxidation ultraviolet systems, or peroxide solutions), and biological treatment (using trickling filters, anaerobic, activated sludge, and rotating biological contactors). Exhausted carbon from adsorption processes may be sent for regeneration or combustion. In some cases, air or steam stripping is performed to remove organics. Toxic metals are precipitated and filtered out.
Where appropriate, a pharmaceutical manufacturing plant should prepare a hazard assessment and operability study and also prepare and implement an Emergency Plan which takes into account neighboring land uses and the potential consequences of an emergency. Measures to avoid the release of harmful substances should be incorporated in the design operation, maintenance, and management of the plant.

Pollution Reduction Targets
Implementation of cleaner production processes and pollution prevention measures can provide both economic and environmental benefits.
Solid Wastes
Specific reduction targets for the different processes have not been determined. In the absence of specific pollution reduction targets, new plants should always achieve better than the industry averages quoted in the section on Waste Characteristics and should approach the effluent levels. The table in the Emissions Requirements section presents the maximum effluent levels after the addition of pollution control measures
Contaminated solid wastes are generally incinerated and the flue gases are scrubbed. Combustion devices should be operated at temperatures above 1,000
C with a residence time of at least one second to achieve acceptable destruction efficiency (of over 99.99 percent) of toxics. However, temperatures of around 900
C are acceptable provided at least 99.99 percent destruction/removal efficiency of toxics is achieved.
For controlling air emissions, install vapor recovery systems. Recycle wastewaters and treated effluents to the extent feasible.
Emissions Requirements
Emission levels for the design and operation of each project must be established through the Environmental Assessment (EA) process, based on country legislation and the

No comments: