2 Introduction - Parenterals Sterile Products are dosage forms of therapeutic agents that are free of viable micro organisms. These includes parenterals, ophthalmic products & irrigating solutions.Sterile products are most frequently solutions or suspensions, but may even be solid pellets for tissue implantation.The term “parenteral” means pertaining to outside the intestines. When referring to parenteral medication, means to deliver medication via a route other than through digestive tract. The most common route used to deliver parenteral medication is through injection.Parenteral preparations may be given by various routes – Intravenous, Intraspinal, Intra muscular, subcutaneous & Intradermal, etc.All components & processes involved in the preparation of these products must be selected & designed to eliminate, contamination of all types, whether physical, chemical or microbiologic origin.
3 Advantages of Parenterals Parenterals are unique among dosage forms of drugs because they are injected through the skin or mucous membranes into internal body compartments. Parenterals are useful for patients who cannot takes drug orally & in emergency situation.Drugs may be injected into the specialised area of the body, including joints (intra articular), joint fluid area (intra synovial), spinal column (intra spinal), spinal fluid (intra thecal), arteries (intra arterial) and in emergency, even the heart (intra cardiac).Parenterals possess better & faster onset of action & bioavailability than other dosage forms (solid & liquid orals etc). Biologic products viz- peptide hormones, vaccines, toxoids and antitoxins are best suited for parenteral route of administration.Useful for drugs that are inactivated in the GIT or susceptible first pass metabolism by liver.
4 Advantages of Parenterals Parenteral products could be administered as sterile solution during an irrigation procedure as these solutions can enter the blood stream directly through open blood vessels of wounds or abraded mucous membranes.Sterile parenteral products could be administered even as solid pellets/tablets for tissue implantation and useful for providing sustained drug delivery (depot injection).Parenterals as a dosage form scores better over other conventional dosage forms (solid/liquid orals) for administration of special categories of drugs like anticancer agents, immunosupressants, hormones & peptides, radio opaque & diagnostic agents etc.Useful for delivering fluids, electrolytes or nutrients (total parenteral nutrition) to patients.
5 Disadvantages of Parenterals More expensive & costly to produce as compared to other formulations.Potential for infection at the site of injection, thrombophlebitis, extravasation, fluid overload & air embolism.Risk of needle stick injuries & exposure to blood borne pathogens by health care workers.Disposal of needles, syringes & other infusion devices requires special consideration.Improper injection procedures could cause damage to the patient’s nerves, tissue, veins & other blood vessels.The presence of traces of physical/chemical contaminants cause irritation to body tissues & also leads to degradation of product due to chemical change when thermal sterilisation is employed.Example: Minute traces of copper increases the rate of oxidation of ascorbic acid in solution. The contamination arises from water or chemical components or even the container.
6 Routes of administration Intravenous route (IV)IV injection of drugs provide rapid action compared with other routes of administration and because drug absorption is not a factor, optimum blood levels may be achieved with accuracy which is not possible by other routes.In emergencies, IV administration of a drug may be life saving because of placement of drug directly into the circulation and on the negative side, once a drug is administered intravenously, it cannot be retrieved.Both small and large volumes of drug solutions may be administered intravenously. IV drugs must be in aqueous solution, they must mix with the circulating blood & not precipitate from solution.
7 Routes of administration Intramuscular route (IM) – IM injections of drugs provide effects that are less rapid but generally longer lasting than those obtained from IV administration. Aqueous or oleaginous solutions or suspensions of drug substances may be administered intramuscularly. IM injections are performed deep into skeletal muscles. Subcutaneous route (SC) – This route may be used for injection of small amounts of medication. Injection of a drug beneath the skin is usually made in the loose interstitial tissue of the outer upper arm, the anterior thigh, or the lower abdomen. Prior to injection, the skin at injection site should be thoroughly cleansed. Irrigating drugs and those in thick suspension may produce induration, sloughing or abscess & may be painful. Such preparations are not suitable for SC injections. Intradermal route – A no.of substances may be effectively injected into the corium, the more vascular layer of skin just beneath the epidermis. These substances includes various agents for diagnostic detections, desensitisation or immunisation. The usual site for intradermal injection is the anterior forearm.
8 Water for Injection (WFI) WFI – It is non-pyrogenic distilled water meant for use in preparations of medicines for parenteral administration. WFI is obtained by distilling potable water or purified water from a neutral glass, quartz or suitable metal still fitted with an effective device for preventing the entrainment of droplets. The 1st portion of distillate is discarded & the remainder is collected & stored in conditions designed to prevent the growth of microbes & to avoid any other contamination.Sterile WFI – It is WFI distributed in suitable containers of glass or any other material, sealed & sterilised by heat under conditions that ensure that water remains non-pyrogenic. Each container contains a suitable quantity of WFI to permit the withdrawl of nominal volume.IP standards & QC tests – 1) Clarity & colour2) Acidity/alkalinity3) Oxidisable substances4) Bacterial Endotoxin Test (BET)5) Sterility test6) Residue on evaporation.Pyrogenecity – Pyrogens are metabolic products of microbes (bacteria,viruses & mould) and may be present in water. Pyrogens are lipids associated with carrier molecule usually a polysaccharide or peptide. Pyrogens when injected through ear vein of rabbits causes marked rise in body temperature (hyperthermia) within 1 hour of injection. Pyrogens can be eliminated by heating the containers at 210◦C for 3-4 hrs and can be removed from solutions by adsorption on surface of selected adsorbent.
9 Excipients/Additives used in parenterals Vehicle – The most frequently employed vehicle for sterile products is water, as it is the vehicle for all natural body fluids. The tests for checking water quality includes a) Total solid content b) gravimetric evaluation of organic & inorganic substances c) Electrolytic measurement of conductivity. The additional tests for quality of WFI (water for injection) is described in USP monograph. The another vehicle sterile WFI has been sterilised by a thermal method, WFI should not have a conductivity of more than 1micro mho.Non aqueous vehicles – It must be selected with great care as it must be non irritating, non toxic & must not exert an adverse effect on ingredient of formulation. These must be included because of limited water solubility of a medicinal substances or it’s susceptibility to hydrolysis. The screening includes testing of it’s physical properties such as density, viscosity, pH, miscibility, boiling point, low vapour pressure & polarity etc.The United States Pharmacopoeia (USP) specifies restrictions on the use of fixed oils and they must remain clear when cooled to 10○C to ensure stability and clarity of injectable product during refrigeration.
10 Excipients/Additives used in parenterals The oils must not contain mineral oil or paraffin as these materials are not absorbed by body tissues. The most commonly used fixed oils in injections are corn oil, cottonseed oil, peanut oil & sesame oil. Examples: Water miscible solvents are butylene glycol, Poly Ethylene Glycol (PEG) 400,600, glycerol, ethanol, propylene glycol. Water immiscible solvents include fixed oils, ethyl oleate, isopropyl myristate & benzyl benzoate 3) Solutes – It should be free from pyrogenic & microbial contamination. The physical & chemical purity of solutes used for sterile preparations should be considered. For a few substances ex – Vitamin-C, calcium gluconate special parenteral grades are available. 4) Added substances – It includes solubilisers, antioxidants, chelating agents, buffers, tonicity builders, antibacterial agents, hydrolysis inhibitors, antifoaming agents.
11 Common excipients used in parenterals S.NoExcipientsConcentration range (%)1Anti microbial preservativesBenzyl alcoholPhenyl mercuric nitrateThimerosalPropyl paraben0.5 – 10.00.0012Solubilisers, wetting agents/emulsifiersDimethyl acetamideEthanolGlycerolPEG 3000.010.61 – 49.03Buffersa) Acetic acidb) Citric acidc) Maleic acidd) Lactic acid0.220.51.60.14Tonicity modifiersLactoseMannitolSorbitolNacl2.0varies
12 Common excipients used in parenterals S.NoExcipientsConcentration range5Suspending agentsGelatinPectinPEG 40002.00.26Anti oxidantsAscorbic acidThioureaBHT0.0057Local AnaestheticsProcaine HclBenzyl alcoholStabilisersNiacinSodium caprylateGlycineChelatesEDTA disodiumEDTA tetrasodium1.05.00.40.01
13 Isotonicity & method of adjustments Biologic systems are compatible with solutions having similar osmotic pressures, that is an equivalent no.of dissolved species. For example RBC’s, blood plasma and 0.9% Nacl solution contains approx the same no.of solute particles per unit volume and are termed iso-osmotic & isotonic.Compounds contributing to the isotonicity of a product reduce the pain of injection in areas with nerve endings. Buffers may serve as tonicity contributors as well as stabilisers for pH.An Osmol (Osm) is related to a mole (gm mol wt) of the molecules or ions in solution. One mole of glucose (180 g) dissolved in 1000 g of water has an osmolality of 1 Osm or 1000 mOsm/kg of water. One mole of Nacl ( =58.5 g) dissolved in 1000 g of water has an osmolality of almost 2000 mOsm, since Nacl dissociates into almost 2 particles per molecule. In other words, 1 molal solution of Nacl is equivalent to 2 molal solution of dextroseNormal serum osmolality values are in the vicinity of 285 mOsm/kg (often expressed as 285 mOsm/L), ranges may include values from about mOsm/L. Pharmaceuticals should be close to this value to minimise discomfort on application to the eyes/nose on application.
14 Method for calculating isotonicity A sodium chloride (Nacl) equivalent is the amount of Nacl that is osmotically equivalent to 1 gm of drug. For example the Nacl equivalent of ephedrine sulfate is 0.23, that is 1gm of ephedrine sulfate is equivalent to 0.23 gm of Nacl.Q1) How much Nacl is required to make the following prescription isotonic?Rx – Ephedrine sulfate 2%, sterile WFI – q.s 30 ml, make isotonic with Nacl.30 ml * = g Nacl is required.30 ml* 0.02 = 0.6 g ephedrine sulfate is to be present0.6 g* 0.23 = g is the quantity of Nacl represented by ephedrine sulfateSince g Nacl is required if only Nacl is used & quantity of Nacl that is equivalent to 0.6 g of ephedrine sulfate is g, then = g of Nacl required to render solution isotonic.Therefore the solution requires ephedrine sulfate 0.6 g, Nacl g and sufficient sterile WFI to make 30 ml.
15 Small & Large Volume Parenterals The term Small Volume Parenteral(SVP) has been officially defined by USP as “an injection that is packaged in containers labeled as containing 100ml or less” & Large Volume Parenteral(LVP) applies to injection that is intended for IV use & packaged in containers holding 100 ml or more (1 litre). The term LVP means a terminally sterilised aqueous drug product packaged in a single-dose container with a capacity of more than 100ml intended for use in man. Sterile liquid products are classified as SVP’s & LVP’s. The SVP’s includes pharmaceutical products (otic, ophthalmic & parenterals) Diagnostic agents, allergenic extracts ,radiopharmaceuticals & biologicals. The parenteral preparations may be solutions, suspensions, emulsions and powder for reconstitution. The LVP’s includes blood collecting units with anticoagulants, peritoneal dialysates, irrigating solutions, diagnostic agents & IV fluids (solutions & emulsions).
16 Differences between SVP & LVP S.NoSmall Volume Parenterals (SVP)Large Volume Parenterals (LVP)1SVP’s are sterile, pyrogen free injectable products that are packaged in vol’s up to 100 mlLVP’s are sterile, pyrogen free injectable products that are packaged in vol’s more than 100 ml (1litre)2Some SVP aqueous solutions can be administered only by IV route because of local irritationLVP’s are administered by intra or extra vascular routes depending on composition.3SVP’s are usually packed in vials, ampoules of small sizesLVP’s are packed in large containers (glass/plastic of 1 litre capacity)4SVP’s include drugs in suspension, emulsion, freeze dried product or powder for reconstitution. The other products include biological & diagnostic agents, allergenic extracts, radiopharmaceuticals, dental products, liposomes & lipids etcLVP’s includes saline solutions, dextrose solution, ringers solutions, peritoneal dialysates, irrigating solutions, diagnostic agents & blood collecting unit with anticoagulants.
17 Manufacture of SVP’s1) Planning & scheduling of functions- 4 groups of personnels were involved a) material management b) personnel management c) equipment & facilities maintenance d) documentation control.2) Material management – A group of personnel(s) are responsible for providing materials necessary to manufacture the product.3) Personnel management – Appointment of a properly motivated production staff who will be given training to perform their job.4) Documentation control – It is the control & verification of critical activities in a pharmaceutical process production & control cycle.Examples of documents to be maintained are as follows –Master fileBatch recordsStandard Operating Procedures (SOP’s)Validation recordsEnvironmental recordStability recordsProcess logs & material logsComplaint files, returned good recordsRetained sample storage area records
18 Manufacture of SVP’s5) Equipment & facilities management – There are several types of equipment that are used in overall processing of SVP’s. The examples areWashing equipment (glass, plastic & rubber components)Mixing equipment to manufacture the bulk productFiltering equipment to clarify & or sterilise productStorage tanks to hold the bulk product prior to sub divisionFilling or subdividing equipmentStoppering & or scaling equipmentTerminal sterilisation equipment.Preparation of facilities – a) cleaning of service areas b) preparation of clean room areas c) preparation of sterile room d) preparation of equipment.7) Preparation of packaging components – A sterile package consist of primary & secondary packaging components. Examples of primary packaging components are ampoules, vials, syringes, syringe cartridges, squeeze bottles & rubber/plastic stoppers. A box or a shrink wrap is an secondary packaging components
19 Production facilities for an aseptic processing of parenterals The functional parenteral production areas involved areWarehousing or procurement.Compounding or formulation.Materials (containers, closures & equipment).Preparation area.Filtration & sterile receiving area.Aseptic filling.Stoppering.Lyophilisation & packaging.Labeling.Quarantine.The design & control of an aseptic area is directed towards reducing the presence of these contaminants (dust, lint, microbes, suspended particles in air) so that they are no longer a hazard to aseptic filling.
20 AIR CONTROL & CLEAN ROOM FACILITIES FOR PARENTERALS Air cleaning – Since air is one of the potential source of contaminants in clean rooms, special attention must be given to air being drawn into clean rooms by heating, ventilation & air conditioning (HVAC) systems.Air control in sterile areaFresh outside or recycled air must be 1st filtered to remove particulate matter. A spun glass, cloth or shredded polyethylene filter may be used for preliminary cleaning operations.To remove finer debris down to sub micron range, including microbes, a HEPA filter, defined atleast 99.97% efficient in removing particles of 0.3µm size & larger & composed of glass fibers & fillers or electrostatic precipitators, can be employed. Air passing thru these units can be rendered virtually free from foreign matter.Blowers should be installed in the air ventilation system upstream to the filters so that all dirt producing devices are ahead of the filters. The clean air is normally distributed to the required areas by means of metal (stainless steel) ducts.
21 AIR CONTROL & CLEAN ROOM FACILITIES FOR PARENTERALS The clean aseptic air is distributed in such a manner that it flows into the maximum security room at the greatest volume flow rate thereby producing a positive pressure in these areas. This prevents unclean air from rushing into the aseptic area thru cracks, temporarily opened doors, or other openings.A relatively new air control system based on laminar flow principles has improved the potential for environmental control of aseptic areas. Currently, it could able to achieve a class 100 clean room.A class 100 clean room is defined as a room in which the particle count in the air is NMT 100 per cubic foot of 0.5µm & larger in size. HEPA filtered air is blown evenly out of entire back or top of a work bench or entire side or ceiling of a room. The air flow must be uniform in velocity & direction throughout any given cross section of the area, being exhausted from opposite side.The air velocity employed should be 100±20 ft/min. Contamination is controlled because it is swept away with the air flow. The vertical flow from ceiling mounted HEPA filter units, is utilised to protect critical sections of processing lines & most frequently for work benches.
22 AIR CONTROL & CLEAN ROOM FACILITES FOR PARENTERALS Although class 100 work environment are normally specified for most critical aseptic & or clean operations, achieving such levels of cleanliness is expensive & requires effective maintenance & monitoring.A class 10,000 room is one in which the particle count is not more than 10,000 per cubic foot of 0.5µm & larger in size. Such a cleanliness level is considered suitable for buffer areas around class 100 work sites in which operations such as handling, precleaned containers, process filtration & aseptic gowning of personnel may be performed.Biologic evaluation methods used includes settling & surface contact nutrient agar plate, air impingement on nutrient media, membrane filtration, electronic particle counters etc.
23 Clean room classified areas for parenterals European gradeUS classificationInternational society of Pharm engg descriptionMax no.of particles per cubic meterA100Critical3,500BCleanC10,000Controlled350,0002,000D100,000Pharmaceutical3,500,00020,000
24 Aseptic areas & facilities for parenterals The aseptic area requires construction features designed for maximum microbial & particulate control. The ceiling, walls & floor must be sealed so that they may be washed & sanitised with a disinfectant, as needed.All light fixtures, utility service lines & ventilation fixtures should be recassed in walls/ceiling to eliminate ledges, joints & other locations for accumulation of dust & air.The tanks containing compounded product should remain outside aseptic filling area & product fed into area thru hose lines. Proper sanitation is required if the tanks must be moved in.Large mechanical equipment that is located in aseptic area should be housed as within stainless steel cabinet to seal the operating parts & their dirt producing tendencies from aseptic environment.
25 Aseptic area & facilities for parenterals Personnel entering the aseptic area should enter only thru an airlock. They should be attired in sterile coveralls with sterile hats, masks, goggles & foot covers. Movement within the room should be minimal & in & out movement rigidly be restricted during filling procedure.Aseptic area operators should be given formal training in the principles of aseptic processing, fresh, sterile uniforms should be used after every break period or whenever the individual returns to aseptic area.Gowning rooms should be designed to enhance pre gowning and gowning procedures by trained operators so that it is possible to ensure continued sterility of exterior surfaces of sterile gowning components. De-gowning should be performed in separate exit room.
26 Formulation of parenterals The preparation of a parenteral solution involves the dissolution of all the ingredients into an appropriate solvent system. The most common solvent is water. The cosolvents such as aqueous/glycol mixtures to improve the solubility. Occasionally, non aqueous systems such as vegetable oils are used when aqueous & cosolvent systems are inadequate to dissolve active drug.A sterile solution may contain one or more following additivesa) Osmotic pressure adjusters – NaCl, mannitol.b) Bacteriostatic agents – Benzyl alcohol.c) Buffering agents – Phosphates, acetates & citrates.d) Antioxidants – Bisulfite, ascorbate & citrate.e) Chelates – EDTA to sequester heavy metals which catalyse degradation.In case of formulating a new compound, in formation related to basic properties such as mol.wt, solubility, purity, colligative properties, chemical reactivity etc to be considered.Inert gases have been used to displace oxygen from a solution & reduce the possibility of oxidative changes in the formulation. Inert gases may be used to stabilise solutions.
27 Formulation of parenterals Operation-I (Non sterile)Place WFI into a clean, vented, glass lined/stainless steel pressure tank. A starting volume in excess of 10% of final volume is recommended to cover losses due to evaporation during heating. Seal the pressure tank.Heat WFI to 121 deg C & maintain for 20 min while gradually releasing tank pressure. Then cool to 60 deg C.Remove & place in a separate vented SS or glass container of suitable capacity a qty of WFI equal to about 30% of final formula volume & save for final vol adjustment.To remaining WFI (at 60 deg C), from step-2, add & dissolve with stirring to monobasic & dibasic sod phosphate. Care must be taken that phosphate salts are dissolved.Allow the solution from step-4 to cool to RT (25-30 deg C), then add and dissolve with stirring water soluble drug & preservative, check the pH of solution if required adjust to with approx 1N NaoH solution.Bring the bulk to final volume with WFI & mix well.
28 Formulation of parenterals Operation-II (Sterilisation)Sterilise the bulk solution from operation-1, step 6, by filtration thru a sterile sterilising membrane, with an appropriate non shedding preclarification filter.Collect the sterile filtrate directly from sterilising membrane via sterile tubing & siphon into a sterile, clean, closed, vented, SS tank or glass vessel.Operation-III (Sterile subdivision)Aseptically subdivide sterile bulk solution into an appropriate sterile container.Aseptically apply sterilised closure systems to container & seal.Sample across filtering operation at intervals determined by QC standards for sterility tests & vol fill checks.Visually inspect all units for defects & particulate against a well lighted black & white background.Submit samples to QC lab for release assays.
29 Lyophilisation & preparation of sterile powders Injections are also packaged as dry solids rather than in conjuction with solvent or vehicle because therapeutic agent is unstable in the presence of liquid component. These dry powders are packaged in the final container to be reconstituted, generally to a solution or less frequently a suspension. The method of sterilisation of powder may be dry heat or other appropriate method. Antibiotics are prepared industrially in large fermentation tanks. Sometimes liquid is packaged with dry powder for use at the time of reconstitution. This liquid is sterile & may contain some of the desired additives such as buffer. Lyophilisation (freeze dried products) – Solutions intended to be freeze dried must be aqueous, for the drying process involves removal of water by sublimation. The formulation must reflect the characteristics to be imparted to the solid residue (cake) after drying & those required of the solution after reconstitution at the time of use. The characteristics required of a good cake are 1) A uniform colour & texture 2) A supporting matrix of solids sufficient to maintain essentially the original volume after drying and 3) Sufficient strength to prevent crumbling during storage.
30 Lyophilisation & preparation of sterile powders The % of solids in the frozen plug is between 2 & 25%. When organic substances such as mannitol, sorbitol, sucrose & gelatin are used to provide solids for the cake, care must be taken during heating, particularly during the terminal stages of drying, to avoid discoloration of cake by charing.Added substances required in the formulation must not be volatile under the conditions of drying, therefore antibacterial agents such as phenol, chlorobutanol & benzyl alcohol must not be used. Suspensions of drugs for parenteral use may be prepared by reducing the drug to a very fine powder with a ball mill, microniser, colloid mill or other appropriate equipment & then suspending the material in a liquid in which it is insoluble.It is frequently necessary to sterilise separately the individual components of a suspension before combining them, as the integrity of the suspension is destroyed by autoclaving. It may alter the viscosity of product, affecting the suspending ability of the vehicle, or change the particle size of suspended particles, altering both pharmaceutical & therapeutic characteristics. If a suspension remains unaltered by autoclaving this method is generally employed to sterilise the final product.
31 Containers for parenterals Glass – It includes ampoules, vials, 1 litre bottle or more capacityPlastic – 1 litre capacity or moreRubber – closure material sealed with aluminiumGLASS– The glass used in manufacture of such containers (ampoules,vials, bottles etc) complies with one of the requirements for hydrolytic resistance. There are 3 types of glass used, the types are distinguished by resistance to water attack of new glass containers, the degree of attack being determined by amount of alkali released from the glass under specified conditions.Type-I (Neutral glass) – It offers a high hydrolytic resistance due to chemical composition of glass. It is also called borosilicate glass.Type-II (treated soda lime glass) – It has a high hydrolytic resistance due to an appropriate surface treatment.c)Type-III (regular soda lime glass)- It offers only a moderate hydrolytic resistance & should be used only for non-aqueous liquid preparations or for powders for injection or for injectable preparations where adequate suitability tests have indicated for other dosage forms.d) NP – General purpose Not for Parenteral soda lime glass.
32 Containers for parenterals PLASTIC: The principal ingredient of various plastic materials used for container is thermoplastic polymer. All of the polymeric materials except low density polyethylene & polystyrene can be autoclaved if they have been formulated with low amount of plasticizers.Plastic containers are used mainly because of light in weight, non breakable, low toxicity & low reactivity with products. Polyethylene and Polypropylene are the most commonly used polymer. The USP has provided test procedures for evaluating toxicity of plastic materials. The test consist of 3 phasesImplanting small pieces of plastic material (IM route) in rabbitsInjecting eluates using Nacl injection, with & without alcohol, intravenously in mice & injecting eluates using PEG 400 & sesame oil intraperitoneally in miceInjecting all 4 eluates subcutaneously in rabbits. The reaction from test samples must not be greater than non reactive control samples.
33 Closures for Parenterals Rubber Closures: These are used to seal the openings of cartridges, vials and bottles providing a material soft & elastic enough to permit entry & withdrawl of a hypodermic needle without loss of integrity of sealed container. Composition of Rubber Closure: It is made up of natural rubber (latex) & or a synthetic polymer, a vulcanising agent (sulfur), an accelerator (2-mercaptobenzothiazole), an activator (Zno), filler (carbon black/limestone) and other ingredients such as antioxidants & lubricants. The compatibility of rubber closures with the drug product is assessed by placing the closure in contact with the drug product & maintaining the samples at elevated temperature levels for planned periods of time. At prescribed intervals, samples are examined for quantitative and qualitative evidence of chemical/physical change either in the closure or in the product. Physical Characteristics: Several properties of rubber closures are significant, particularly elastic, hardness & porosity. Rubber closures must be sufficiently elastic to provide a snug fit between the closure & the neck
34 Closures for Parenterals and lip of glass containers. The physical shapes of closures vary with their intended use. The common shapes are flanged closure (center), slotted for freeze dried products, punctured for attachment of adapters for infusion sets & the plunger type for use with cartridge. Testing of Rubber Closure: The USP describes physico chemical tests on aqueous extracts include pH, turbidity, residue on drying, Iodine number & heavy metals content. The biologic tests on saline, PEG 400 & cottonseed oil extracts include acute & chronic toxicity in mice & rabbits.
35 Test for Hydrolytic resistance (Limits for alkalinity) for glass containers The selected no.of containers should be rinsed atleast twice with water at RT. Just before the test rinse each container with freshly prepared distilled water. Fill the containers to the brim with freshly prepared distilled water, empty them & determine the average over flow volume.Fill ampoules with freshly preparaed distilled water to the max volume & seal them by fusion. Fill bottles/vials to 90% of their calculated overflow volume & cover with borosilicate glass dishes/aluminium foil previously rinsed with freshly prepared distilled water.Place the containers in an autoclave containing water so that they remain clear of water. Close the autoclave, displace the air by passage of steam for 10 mins, raise the temperature from 100 to 121 deg C over 20 mins, maintain the temperature of 121 deg C for 60 mins & reduce the temperature from 121 to 100 deg C over 40 mins, venting to prevent vacuum.Remove the containers from autoclave & cool them in a bath of running tap water. Carry out the following titration within 1 hr of removing the containers from autoclave. Combine the liquids from the containers being examined, measure the vol of test solution & add 0.15 ml of methyl red solution for each 50 ml of liquid, titrate with 0.01M Hcl taking as the end point the colour obtained by repeating the operation using same volume of freshly prepared distilled water.
36 Test for Hydrolytic resistance (Limits for alkalinity) for glass containers The difference between the titrations represents the vol of 0.01M Hcl required by the test solution. Calculate the volume of 0.01M Hcl required for each 100 ml of test solution if necessary. The result is NMT value stated in an oven at 130 deg C for ½ hr. Cool, add to the residue 10 ml of hydrazine-molybdate reagent, swirl to dissolve & heat under reflux on a water bath for 20 mins.Cool to RT. Determine the absorbance of resulting solution at max at about 840 nm, using 10 ml of hydrazine-molybdate reagent as blank. The absorbance of test solution does not exceed the absorbance obtained by repeating the determination using 0.1 ml of arsenic std soln (10 ppm As)in place of test solution (0.1 ppm)
37 Test for Sterility (as per IP) It is intended for detecting the presence of vianle forms of microorganisms in parenteral preparations. The tests are based upon the principle that is microbes are placed in a medium which provides nutritive material & water kept at favourable temperature, the organisms will grow & their presence can be indicated by a turbidity in the originally clear medium.The probability of detecting viable microbes in the tests for sterility increases with the number present in a given amount of preparation being examined & varies according to the species of microbes present. Very low levels of contamination can’t be detected on the basis of random sampling of a batch.A batch may be defined for the purpose of these tests as homogeneous collection of sealed containers prepared in such a manner that the risk of contamination is the same for each of the units in it.The tests for sterility are designed to reveal the presence of microbes in the samples used in the tests. Interpretation of results is based on assumption that contents of every container in the batch, had they been tested, would also have complied with the tests. Since every container can’t be tested, a sufficient no.of containers should be examined to give a suitable degree of confidence in the results of the tests.
38 Test for Sterility (as per IP) The official USP methods include direct inoculation test & filtration test methods (using membrane filtration). The false negative results of a direct inoculation test also may occur as a result of antibacterial activity inherent in the product. A false negative results also may be obtained if the microbial population is so small that the inoculum taken from the product does not contain a microorganism.A false positive test result could be caused by inadvertent contamination during the test. Such false results can be eliminated by the use of carefully & adequately trained personnel working in a properly controlled environment.Methods of Sterilisation –Thermal methods – Dry heat, Moist heat (using steam).Non thermal methods – UV light, ionisation radiations.Chemical methodsa) Gaseous sterilisation – Ethylene oxide, Beta propiolactone4) Terminal sterilisation using autoclave
39 Filling & Sealing of Parenterals Filling equipment for liquids – A measured vol.of liquid is forced through the orifice of a delivery tube designed to enter the constricted opening of a container. The size of the delivery tube is governed by the opening in the container to be used, the viscosity & density of the liquid & speed of delivery desired.The tube must freely enter the neck of the container & deliver the liquid deep enough to permit air to escape without sweeping the entering liquid into the neck or out of the container. To reduce the resistance to the flow of liquid, the tube should have the max possible diameter. Excessive delivery force causes splashing of the liquid & troublesome foaming, if the liquid has a low surface tension.Filling machines should be designed so that the parts through which the liquid flows can be easily demounted for cleaning & sterilisation. These parts should be constructed of non-reactive materials such as borosilicate glass/SS. Syringes are usually made of SS when the pressure required for delivery of viscous liquid or large volumes would be unsafe for glass syringes.
40 Filling & Sealing of Parenterals The pressure pump filler often is operated semi automatically & differs from gravity filler principally in that the liquid is under pressure. It is usually equipped with an overflow tube connected to a receiver to prevent excess filling of the container.Vacuum filling is commonly used in tester filling lines for large volume of liquids because it is more adaptable to automation. A vacuum is produced in a bottle when a nozzle gasket makes a seal against the lip of the bottle to be filled.The vacuum draws the liquid from a reservoir through the delivery tube into the bottle, when the liquid level reaches the level of adjustable overflow tube, the seal is mechanically loosened & vacuum is released.Filling equipment for solids – Sterile solids such as antibiotics are more difficult to subdivide accurately & precisely into individual dose containers than are liquids. The rate of flow of solid material tends to be slow & irregular, particularly if finely powdered. Small, granular particles flow must evenly.
41 Filling & Sealing of Parenterals Sterile solids can be subdivided into containers by individual weighing. The operator can use a scoop that holds a vol approx equal to the weight required, but the quantity filled into the container is finally weighed on a balance.One type of machine for delivering measured quantities of free-flowing material employs an auger in the stem of funnel shaped hopper. The size & rotation of auger can be adjusted to deliver a regulated vol of granular material from the funnel stem into the container.In another filling machine, an adjustable cavity in the rim of the filling wheel is filled by vacuum as the wheel passes under the hopper. The contents are held by vacuum until the cavity is inverted over the container, when a jet of sterile air discharge the dry solids. This machine dispenses only dry solids that flow less freely than those of other machines presently available.Sealing of parenteral products – Containers should be sealed in the aseptic area immediately adjacent to the filling machine. In addition to retaining the contents of a sterile product, sealing of containers assures the users that it has not been opened.
42 Filling & Sealing of Parenterals Sealing of ampoules – It may be closed by melting a portion of the glass of neck to form either bead seals (tip-seals) or pull seals. Tip seals are made by melting sufficient glass at the tip of ampoule neck to form a bead of glass & close the opening. Pull-seals are made by heating the neck of rotating ampoule below the tip, then pulling the tip away to form a small, twisted capillary just prior to being melt closed.The heating with a high temperature gas oxygen flame must be even & carefully controlled to avoid gas distortion of the seal. Excessive heating of air & gases in the neck causes expansion against the soft glass with the formation of fragile bubbles at the point of seal. Pull sealing is a slower process & more reliable than tip sealing. Powder ampoules or other types having a wide opening must be sealed by pull-sealing.It is some times necessary to displace the air in the space within the ampoule above the product to prevent decomposition. This may be done by introducing a stream of inert gas (N2 or CO2) during/after filling with the product. Immediately thereafter the ampoule is sealed before the gas can diffuse to the outside.
43 Sealing of ampoulesSealing bottles, cartridges & vials – When closures are to be inserted by machines, the surface of the closure is usually halogenated/coated with silicone to reduce friction. Aluminium caps are used to hold rubber closures in place. Single caps may have a permanent center hole or a center that is torn away at the time of use to expose the rubber closure. Double aluminium caps usually have a inner cap with a permanent center hole which in use is exposed when the entire outer cap is torn off. The triple aluminium caps are used for large bottles with rubber closures having permanent holes for attachment to administration sets.
44 Evaluation (QC Tests) for Parenterals The 3 general areas of QC are incoming stock, manufacturing & finished products. It is also necessary to perform microbial load (bioburden) tests to determine the no & types of microbes present.In addition to the usual chemical & biologic tests, a sterile product is subjected to a leaker test, a clarity test, a pyrogen test & a sterility test. The production control includes all of the final assays & tests to which the product is subjected.1) Leaker test - The leaker test is intended to detect incompletely sealed ampoules so that they may be discarded. Tip-sealed ampoules are more likely to be incompletely sealed than that of pull sealed. In addition, small cracks may occur around the seal or at the base of ampoule as a result of improper handling.Leakers are detected by producing a negative pressure within an incompletely sealed ampoule, usually in a vacuum chamber, while the ampoule is entirely submerged in a deeply coloured dye solution (usually % methylene blue). Subsequently atmospheric pressure then causes the dye to penetrate an opening being visible after the ampoule has been washed externally clear it of dye.
45 QC tests for parenterals The vacuum (27 inches Hg or more) should be sharply released after 30 min. Only a tiny drop of dye may penetrate a small opening. The detection of leaker is more effective when the ampoules are immersed in a bath of dye during the autoclaving cycle.Another test is to apply a spark tester probe to the outside of bottle, moving from the liquid layer into the air space. A blue spark discharge occurs if the air space is evacuated.2) Clarity test – The USP states that good pharmaceutical practice requires that all containers to be visually inspected & that any with visible particles to be discarded. In addition, for LVP (infusions), the USP has established a limit of 50 particles of 10µm & larger & 5 particles of 25µm & larger per ml.Suspensions, emulsions, or dry solids, in addition to solutions should be compounded & processed under clean conditions to minimise the presence of foreign particles.The visual inspection of a product container is done by individual human inspection of each externally clean container under a good light, baffled against reflection into the eyes & viewed against a black & white background, with the contents set in motion with a swirling action.
46 QC tests for parenterals A moving particle is much easier to see than a stationary one, but care should be taken to avoid introducing air bubbles, which are difficult to distinguish from dust particles.To see heavy particles it is necessary to invert the container as a final step in inspection.Instrumental methods of evaluation for particulate matter in liquids utilising the principles of light scattering, light absorption & electrical resistance have been used to obtain particle counts & size distribution. A method utilising video image projection coupled with electronic circuitry detects moving particles with out destruction of the product unit.3) Pyrogen test (Bacterial endotoxin test) – The presence of pyrogen in parenteral preparations is detected by a qualitative biologic test based on the fever response in rabbits. If a pyrogenic substance is injected into the vein of a rabbit, an elevation of temperature occurs within a period of 3hrs.The housing conditions & handling are critical to obtain a consistent results with rabbits in the test. Because of this the use of rectal thermometers has largely been replaced by rectal thermocouples, which remain in place throughout the test eliminating the handling of rabbits for individual temperature readings.
47 QC tests for Parenterals Recently, an invitro test method for pyrogens has been developed utilising the gelling property of the lysate of amebocytes of limulus polyphemus (horse shoe crab). In the presence of pyrogenic endotoxins from gram negative bacteria, a firm gel is formed within 60 min when incubated at 37 deg C.Although only endotoxins from gram negative bacteria react in this way, they constitute the majority & the most potent of contaminating pyrogens. The LAL (Limulus Amebocyte Lysate) test is 5-10 times more sensitive than rabbit tests & by use of serial dilutions has been shown to be semiquantitative.4) Other test – Sterility testsa) Direct inoculation methodb) Membrane filtration method