Preparation of Sterile Products (Ophthalmic Products)-LAW JIA JUIN

CONTENTS:

A.    OBJECTIVES

B.     INTRODUCTIONS

C.    RESULTS AND OBSERVATIONS

D.    PRECAUTIONS

E.     MARKETED COMPOUNDS

F.     DISCUSSIONS

G.    REFERENCES

A.  OBJECTIVES

1.      To study the methods of preparation for ophthalmic products.

2.      To learn about the concepts of stability and isotonicity of ophthalmic products.

3.      To know about the applicability of ophthalmic products.

B.  INTRODUCTIONS

Ophthalmic preparations or eyes drops are defined as the sterile products that are intended to be administered onto the external surface of the eyes (topical usage) or to be applied into the eyes (intraocular purposes) and this can be applied in conjunction with an ophthalmic device. In general, ophthalmic preparations or eyes drops are those preparations that are designed to deliver solvent or medication like atropine, pilocarpine and carbacholin into the eyes. Ophthalmic eyes drops are used to treat eyes’ diseases like glaucoma and red eyes, it is also used to relieve symptoms like dryness and itchiness, some eyes drops like atropine is widely used for diagnostic and surgical purposes .

Eyes drops are available in many different forms like solutions  ,suspensions ,ointments and even cream. Ophthalmic preparations must be sterile ,clear ,isotonic ,tissue compatibility and pyrogen-free. Some liquid preparations may contain more than one active ingredients .Ophthalmic eyes drops can be classified into prescription or non-prescription type, short term use or prolong use, treatment use or diagnostic purposes.

Prescription eyes drops and non-Prescription eyes drops :	Some eyes drops do not require a prescription, example of them are artificial tears or lubricant. These kinds of drugs are available in most drug stores. However drugs like glaucoma eyes drops do require a prescription from doctor.
Short-term use eyes drops and long term use eyes drops :	Physicians often prescribe antibiotic eyes drops to treat patients with eyes infections. These kinds of antibiotic eyes drops have to be finished even when the symptoms of eyes infections have disappeared. This is known as short term use eyes drops. Another type of prescription medications used for short-term treatment includes steroid eyes drops. Some short term use eyes drops are available in single dose preparations. Which mean that the eyes drops are only designed for a single administration, after that they have to be discarded . On the other hand, long term use eyes drops are those drugs to be used continuously over a long period of time. Patients with dry eyes, should be given the artificial tears or lubricants over a period of time. There are no such thing called single dose eyes drops been designed for long term use ophthalmic preparations.  Another common example of long term ophthalmic eyes drops are glaucoma eyes drops ,it is often a lifetime use eye drops, this is because glaucoma cannot be cured totally ,and it is dangerous as the high pressure inside the eyes can damage the optic nerves and slowly affecting vision. In order to reduce the pressure, doctors often prescribe one or more eye drops that the patient takes every day for a long period of time (usually the patients have to use this eyes drops for a life time).
Diagnostics and therapeutics uses :	In some eyes examinations, the doctors actually use eyes drops to deliver the anti-muscarinic atropine, dilating the pupils so that the doctors will be able to examine the back of the eye like retina examination. Numbing eye drops is also used to check the intraocular eyes pressures .It can also be used to relieve the surface pain induced by foreign objects. But keep in mind that, there are many eyes drops can be used for therapeutic purposes.

               As stated just now, the preparations of aqueous eyes drops require careful consideration from the aspects of isotonicity, buffering capacity, and the desired pH. The presence of antimicrobial agents and/or antioxidants, the use of viscosity-increasing agents, and the choice of appropriate packagings will also improve the qualities and shelf lives of eyes drops produced. Eyes drops are said to be isotonic when the tonicity is equal to 0.9% sodium chloride. The eyes can tolerate solutions with isotonicity equivalent to 0.5–1.8% of sodium chloride. If the tonicity is outside this range (either too high or too low ) then our eyes will be irritated.

Agents like preservative, antioxidant, stabilizer, tonicity modifier, viscosity modifier or buffer should be prepared first. Then the active ingredient is added and the vehicle and made up to volume.

B I). .Types of preservatives that can be used in the preparation of eye drops are:

1.      Main Chemical Preservatives : Chemical preservatives alter cell membrane permeability and lyse (divide) cytoplasmic contents.

2.      Quaternary ammoniums, surfactant and disinfectant agents, among which are benzalkonium chloride, cetremide or cetrimonium chloride or bromide, benzododecinium bromide, miramine, cetylpyridinium chloride, polidronium chloride or polyquarternium-1, polyquaternium-42 (also known as polexitonium), sepazonium, etc.

3.      Mercurial derivatives such as the phenylmercury salts (acetate, borate or nitrate), mercuriothiolate sodium (otherwise called thiomersal or thimerosal) and mercurobutol.

4.      Amidines such as chlorhexidine digluconate or polyhexamethylene biguanide (PHMB).

5.      Alcohols  such as chlorobutanol or phenylethanol,  phenoxyethanol.

6.      Parabens or esters such as parahydroxybenzoic acid,  methylparaben, propylparaben.

7.      Oxidative Preservatives :Oxidative preservatives are able to penetrate cell membranes and interfere with a cell’s functions.

8.      Sodium perborate or GenAqua® which works by oxidizing cell's membranes and disrupting cellular function. When combined with water, sodium perborate is converted to hydrogen peroxide, thus destroying micro-organisms. In contact with the tear film, it converts itself into oxygen and water molecules.

9.      Stabilized oxychloro complex (SOC) or Purite® is a compound usually used for water sanitation.

B II). Examples of antimicrobial agents:

1.Cresol(0.3%)

2.Phenol(0.5%)

3.Benzyl alcohol(1%)

4.Chlorocresol(0.2%)

5.Phenyl mercuric salts(0.002%)

6.Chlorobutanol(0.5%)

7.Thiomersal(0.001-0.004%)

8.Sodium metabisulphite(0.075%)

9.Propyl gallate(0.01-0.20

10.Chlorhexidine gluconate(0.2%)

B.III).Examples of vehicles used in preparation of opthalmic products:

1.         Polyvinyl alcohol(1-4%)-viscosity

2.         Methylcellulose-viscosity

3.         Polyethelyne glycol-viscosity

4.         Carboxy methylcellulose-viscosity

5.         Boric acid(1.9%)-tonicity

6.         Sodium acid-tonicity

7.         Benzalkonium chloride-wetting agents

8.         Polysorbate-20(wetting agents)

9.         Polysorbate-80(wetting agents)

10.       Dioctyl sodium sulphosuccinate(wetting agents)

B IV). Other additives that are added into the preparation of eye drops solution are

·         benzalkonium chloride,

·         borax,

·         boric acid,

·         cetrimide,

·         disodium edentate,

·         phenylmercuric nitrate/acetate,

C.  RESULTS

      C i. Formulations:

1.Atropine sulphate eye drops B.P.C
Atropine sulphate	0.1g
Phenyl mercuric nitrate solution(0.0004%w/v)	5ml
Purified water,to	10ml

2. Physostigmine eye drops B.P.C
Physostigmine sulphate	50mg
Sodium metabisulphite	20mg
Benzalkonium chloride(0.01%w/v)	0.002ml
Purifies water to	10ml

3.Phenylephrine eye drops B.P.C
Phenylephrine hydrochloride	50mg
Sodium metabisulphite	20mg
Sodium citrate	20mg
Benzalkonium chloride(0.01% w/v)	0.002ml
Purified water to	10ml

Cii. Observation

a.Clarity test: Products are put in front white and black background (presence of floating particles give a positive reult)

Eyes drops	Results
Atropine sulphate eye drops by autoclaving sterilization	Negative
Physostigmine eye drops B.P.C by filtration	Negative
Phenylephedrine eye drops B.P.C by heating with bactericide	Negative

b.Sterility test (if there is bacterial growth then the result is said to be positive):

Eyes drops	Results
Atropine sulphate eye drops by autoclaving sterilization	Negative
Physostigmine eye drops B.P.C by filtration	Negative
Phenylephedrine eye drops B.P.C by heating with bactericide	Negative

Ciii Sterilization methods

There were three methods of sterilizations applied in our practical:

1.      Autoclaving sterilization

2.      Filtration using 0.22 µm filtration membrane.

3.      By heating using electronic water bath (100º C for about 30 minutes.)- Not suitable for thermo-labile products.

D.  PRECAUTIONS

1.      The whole uniform, trouser, skin and body parts should be covered completely by the lab cover. There should not have any gaps left or exposed.

2.      Facemask, goggles and gloves should be worn all the time.

3.      A laminar sterile airflow cabinet should be provided with effective heap filters.

4.      Activities in the sterile area should be kept to a minimum and sudden movements should be completely avoided when aseptic work is in progress.

5.      We should sit as close as possible to the laminar flow cupboard. And all the works like filtration and transfer of eyes drops solutions should only be done inside the laminar air flow cupboard.

6.      During the process of filtration, we should works at the centre of cabinet and avoid filtrating the solution at the edge of the laminar flow.

7.      Do not touch the syringe needle & filtration membrane because it might cause contamination.

8.      Do not touch the tip of the dropper bottle.

9.      Sterility testing should only be done in the laminar air flow.

10.  Swirl the vial accordingly for clarity testing

11.  The laminar flow cabinet should be cleaned with a piece of clean tissue paper upon using it, for the convenience of the next user.

E.   EXAMPLE OF MARKETED OPHTHALMIC PREPARATIONS.

ARTIFICIAL TEARS OPHTHALMIC SOLUTION	Lubricant eye drops for fast acting, soothing relief for dry irritated eyes.
REFRESH TEARS	For the moisture of eyes ,removal of irritants Carboxymethylcellulose sodium 5 mg/mL, Sodium chloride, potassium chloride, calcium chloride dihydrate, magnesium chloride hexahydrate, boric acid and sodium borate decahydrate (as buffering agents) and purified water, stabilised oxychloro complex (Purite™) equivalent to 0,005 % m/v stabilised chlorine dioxide, a mild, non-sensitising preservative that, when used, ultimately changes into components of natural tears.
BETOPTIC S	An eye drop treatment for glaucoma, available in either 0.25 percent or 0.5 percent solutions. Betoptic S is a beta blocker and prompts the eye to produce less fluid.
ALPHAGAN P	An alpha agonist and works to both decrease the amount of fluid produced by the eye and to increase drainage.
AZOPT	A carbonic anhydrase inhibitor. This type of drug decreases the amount of fluid produced by the eye.
IOPIDINE	Iopidine is an alpha agonist.
BETAGAN	Betagan is another beta blocker eye drop used to decrease intraocular fluid
BETIMOL	Commonly prescribed for glaucoma sufferers.
OPTIPRANOLOL	A beta blocker eye drop to lowers intraocular pressure.
ISOPTO	Isopto is the brand name for two medications. Isopto Carpine is the drug pilocarpine. Isopto Carbachol has the active ingredient carbachol in the solution. Both medications are cholinergic drugs and promote drainage of ocular fluids.
SODIUM CHLORIDE OPHTHALMIC SOLUTION, USP 5%	For temporary relief of corneal edema.

F.   DISCUSSIONS

In this discussion, I will mainly talk about the working instruments used for ophthalmic preparations.

F1. LAMINAR FLOW

An aseptic work area is achieved by using laminar flow cabinet .It works by cleansing the air when an aseptic (sterile) techniques and a sterile environment are required. Horizontal laminar air flow hoods provide clean air to the work space while providing a constant flow of air out of the work area (towards the user) ,prevents the entering of dusts or small particles into the cabinet from the outside environment or from the body of user. In our practical, the filtration of the ophthalmic solution(used 0.8 µm filtration membrane) ,the sterilization process (used 0.22 µm filtration membrane) as well as the sterility test were all done inside the laminar airflow cabinet

***EXTERNAL AND INTERNA LOOK OF LAMINAR FLOW CABINET.

F2 AUTOCLAVE

In the autoclave process temperature of 120ºC was applied for 20 minutes .It is an effective method for the elimination of contaminants and microbes .An autoclave is an instrument used to sterilize equipment or products. A high pressure is applied to saturate the steam at 121 °C for around 15–20 minutes. The time of autoclave is dependent on the size of the products or the equipment loaded into it. 

The steps of autoclave were recorded and presented as below:

1. Charging with water , pressure =0 Pas

2. Heat to steam , temperature = 23.6 degree celcius , pressure =0 Pas

3. Air purge 97.3 celcius

4. Heat , temp = 104

5. Pressure , temperature = 118.9 degree celcius

5. Sterilization temp=121.4 degree celcius, pressure= 1.15Pas

6.cooling stage 1

7. venting water

8. cooling stage

9. equalizing for 60s

10. safety delay for 30s

A vacuum pump will remove the air from the chamber. Heated steam is introduced into the autoclave via an external pipeline or from a steam generator that is integrated in the sterilizer. The pressure inside the autoclave is increased, and the temperature quickly begins to rise. When the steam reaches 121.4 degrees Celsius, this temperature is maintained for 15 minutes under the pressure of 1.15Pascal.

***EXTERNAL AND INTERNAL COMPONENTS OF AUTOCLAVE MACHINE.

F3 CLARITY TEST APPARATUS

The clarity test was conducted to test for the presence of contaminants, if there was some floating particles been observed the result is said to be positive, which means that the eyes drops solutions were not properly filtered. The product must be observed in front of both black and white background with fluorescence lamp. When viewing at the black background, white or light coloured particles might be seen while when viewing at the white background, dark or black coloured particles can be spotted easily. This is important for clarity test.

EXTERNAL LOOK OF CLARITY TEST APPARATUS, THE INTERNAL PART ONLY CONSIST OF WIRES AND FLUORESCENT LIGHT BULB.

G.  REFERENCES

http://www.torbaycaretrust.nhs.uk/joint_formulary/chapter11/Chp11-full.pdf

http://whqlibdoc.who.int/publications/2003/9241545364_part1.pdf

http://www.drsfostersmith.com/Rx_Info_Sheets/rx_abtc_ophthalmic.pdf

http://www.edeltec.com/usuaris/UserFilesfck/File/Brillenoptik_GB.pdf

http://www.mums.ac.ir/shares/erc/eyecenter/Dr.aghaei.lacri.pdf

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1520227/?page=1