2187 Chemistry And Medicines 3w1h5d

Chemicals in medicines The words ‘medicine’ and 'drug' are often used in our country to mean the same substances: any substance, manufactured artificially, which can help recovery from sickness, relieve symptoms or modify a natural process in the body. A medicine is often a mixture of several chemical compounds. Even if it has only one active component compound often other substances are used as fillers or binders to give it bulk. Chemistry, the science related to chemical substances, provides us the tools to make and study the substances that are the constituents of almost all medicines. The past hundred years or so, ever since the advent of organic chemistry, many chemical compounds have been discovered in nature that are effective for curing diseases. Modern chemistry has also made it possible to synthesize several medicines using methods of organic chemistry. The most common medicines can be classified into few groups, e.g. antibiotics, antiseptics, analgesics, tranquillizers, antipyretics, hormonal, steroids etc. There are very many medicines that come under each of these groups. Often several chemical compounds that make a particular group of medicines, say antibiotics have similar chemical structure. Since the medicines in a particular group are effective for treating a particular type of ailment or disease, their mode of action can also be very similar. But, the methods used to isolate a medicine from its natural sources or to synthesize it are most often very different.

ANTIBIOTICS Our body and our domestic animals, can serve as hosts to a wide variety of diseasecausing organisms (pathogens): These are: • • • •

bacteria viruses fungi protozoon’s

An antibiotic (Greek anti, "against"; bios, "life"), is a chemical substance produced by one organism that is destructive to another. This process traditionally has been called antibiosis and is the opposite of symbiosis. More specifically, an antibiotic is a type of chemotherapeutic agent that has a toxic effect on certain types of disease-producing microorganisms without acting dangerously on the patient. The definition most used for antibiotics is: any substance produced by a microorganism which harms or kills another microorganism. However, antibiotics DO NOT harm viruses. Doctors often prescribe antibiotics when you may have a viral infection because of the possibility that you may also acquire a bacterial infection because you are so ill with a virus - being ill places a

person at risk for certain bacterial infections that are normally handled without any problem. The overwhelming majority of antibiotic substances are natural products that certain bacteria and fungi (molds) produce and send outside of their cells. About 90% of the antibiotics in use today, are isolated from bacteria. There are a few antibiotics, however, which are completely synthetic... that is, are made from scratch in the laboratory. These particular antibiotics are designed to inhibit some process previously identified to be completely unique to bacteria, and necessary for the bacterium to remain alive. An antibiotic can be most often classified into any one of the following categories of chemical compound: 1. 2. 3. 4. 5. 6.

Amino glycosides Glycopeptides Beta Lactams also known as Penicillin’s Tetracycline Quinolines Sulfonamides

Amino glycosides Amino glycosides are antibiotics that are often istered into veins or muscle to treat serious bacterial infections. Some amino glycosides are also used orally to treat intestinal infections or topically to treat eye infections. Some very popular examples of this group of antibiotics are • • • •

Streptomycin Kanamycin Neomycin Gentamycin

They are the inhibitors of protein synthesis, ↓ 30S ribosomal subunit, but some abnormal proteins insert in cell membrane & form pores, thus become bactericidal The chemical structure of this group of antibiotics is:

Glycopeptides Glycopeptide antibiotics are a class of antibiotic drugs. They consist of a glycosylated cyclic or polycyclic nonribosomal peptide. Important glycopeptide antibiotics include vancomycin, teicoplanin, ramoplanin, and decaplanin. This class of drugs inhibits the synthesis of cell walls in susceptible microbes by inhibiting peptidoglycan synthesis. Bacterial cell wall contains peptidoglycan strands • • •

Peptidoglycan is composed of UDP-N-acetyl-muramic acid, UDP-N-acetylglucosamine & a pentapeptide Cycloserine, resembles to alanine & inhibits addition of alanine into peptide chain Vancomycin inhibits transglycosidase enzyme & prevents peptidoglycan chain elongation

Due to their toxicity, their use is restricted to those patients who are critically ill or who have a demonstrated hypersensitivity to the β-lactams. The chemical structure of a glycopeptide antibiotic is

Penicillin Penicillin is one major class of antibiotics. They are used to treat strep throat and countless other infections. Examples of various kinds of penicillin include Amoxicillin, Ampicillin, Carbenicillin, Cloxacillin, Dicloxacillin, Flucloxacillin.. They are the inhibitors of cross linking of peptidoglycan strands: • • • • •

Inhibit transpeptidase enzyme, involved in cross linking of peptidoglycan strands Also called as transpeptidation reaction & strengthens cell wall. Defects in the synthesis of cell wall cause wholes in cell wall & changes in permeability Leading to bacterial swelling & lysis Hence cell wall synthesis inhibitors are bactericidal

Common structural features of Beta-Lactams;

Tetracycline Tetracyclines are another category of antibiotics. In addition to being used to treat infections, they are often used to manage acne. A few of the tetracyclines frequently used are:   

Achromycin V (Tetracycline) Minocin (Minocycline) Vibramycin (Doxycycline)

They are the inhibitors of protein synthesis, ↓ 30S ribosomal subunit & are bacteriostatic The chemical structure of most tetracycline is related to the following structure. The name is derived from the fact that it is made up of four rings (cycles).

Quinolones The quinolones are a family of broad-spectrum antibiotics. The parent of the group is nalidixic acid. The majority of quinolones in clinical use belong to the subset of fluoroquinolones, which have a fluoro group attached the central ring system. Quinolones and fluoroquinolones are bactericidal drugs, actively killing bacteria. Quinolones inhibit the bacterial DNA gyrase or the topoisomerase II enzyme, thereby inhibiting DNA replication and transcription. They are the inhibitors of DNA replication & mitosis, inhibit bacterial topisomerase-II [ in gram (-) bacteria] & topoisomerase IV [in gram (+) bacteria], inhibit DNA replication & are bactericidal The common chemical structure is as follows

Sulfonamides Sulfonamide drugs (known widely as "sulfa drugs") were the first antibacterial antibiotics, and paved the way for the antibiotic revolution in medicine. The first sulfonamide was trade named Prontosil, which is a prodrug. Experiments with Prontosil began in 1932 in the laboratories of the Bayer Corporation, a component of the huge German chemical trust IG Farben. The dye-based drug was synthesized by Bayer chemist Josef Klarer and tested in animals under the direction of physician/researcher Gerhard Domagk. Domagk quickly won the 1939 Nobel Prize in Medicine and Physiology, an honor that Hitler forbade him to accept. They are the inhibitors of DNA & cell division, can affect microbial DNA & cell division in following ways: •

Inhibit DNA synthesis

a) Inhibitors of folate synthesis- Sulfonamides & sulfones inhibit dihydropteroate synthase (DHPS) enzyme Trimethoprim inhibits dihydro-folate reductase (DHFR) enzyme (bacterial DHFR more than human) b) Inhibitors of thymidylate synthesis- Flucytosine: is a cytosine analogue & inhibits thymidylate synthase (TS) • • •

Converted in fungi & GI flora to 5-fluorouracil (5-FU) 5-FU converted to 5-FdUMP 5-FdUMP incorporated to DNA

Some examples of sulfonamide antibiotics are: Mafenide, Sulfacetamide, Sulfamethizole, Sulfanilimide, Trimethoprim etc.

How Antibiotics act. Antibiotics attack a metabolic pathway found in the bacterium but not in the host. This is not an insurmountable problem for bacterial pathogens because they differ in many respects from eukaryotes. Thus pencillins (betalactams) work by interfering with the synthesis of the bacterial cell walls — a structure that is not found in eukaryotes. The walls of bacteria are made of a complex polymeric material called peptidoglycan. It contains both amino acids and amino sugars. The amino sugars are of two kinds • •

N-acetylglucosamine (NAG) and its close relative N-acetylmuramic acid (NAM).

These two form a linear polymer of NAG alternating with NAM. They are linked by a glycosidic bond between the #1 and #4 carbons (this is the linkage attacked by lysozyme) and are oriented in the same way they are in cellulose. Side chains containing 4 or 5 amino acids are attached to each NAM. These form covalent bonds with amino acids in adjacent chains. The bonds may • • •

be direct to the next chain or include additional peptide cross bridges (e.g., 5 glycine residues) which extend to chains in the same plane (shown here) as well as to chains above and below.

This elaborate, covalently cross-linked structure provides the great strength of the cell wall. It also leads to the remarkable conclusion that the bacterial cell wall meets the definition of a single molecule! The beta-lactam antibiotics bind to and inhibit enzymes needed for the synthesis of the peptidoglycan wall. While they have little effect on resting bacteria, they are lethal to dividing bacteria as defective walls cannot protect the organism form bursting in hypotonic surroundings.

The aminoglycosides bind to the 30S subunit of the bacterial ribosome, because the bacterial ribosome differs in several ways from the eukaryotic ribosome and thus interferes with the formation of the initiation complex , causing misreading of the mRNA. Tetracyclines also bind to the 30S subunit of the bacterial ribosome. They prevent the transfer of activated amino acids to the ribosome so protein synthesis is halted. The fluoroquinolones block the action of two bacterial topoisomerases — enzymes that relieve the coils that form in DNA when the helix is being opened in preparation for replication or transcription or repair. block the synthesis of folic acid. Mammals ignore PABA and its analogs and thus can tolerate sulfa drugs. The mode of action of Sulfonamides is a bit different. Both bacteria and their human hosts require folic acid for nucleic acid synthesis (it is converted into prunes and thymidine) as well as protein synthesis (precursor of the amino acids methionine and glycine). However, bacteria synthesize their folic acid starting with para-aminobenzoic acid (PABA), while we must ingest our folic acid already formed; that is, for us it is a vitamin.

Production of antibiotics Since the first pioneering efforts of Florey and Chain in 1939, the importance of antibiotics to medicine has led to much research into discovering and producing them. The process of production usually involves screening of wide ranges of microorganisms, testing and modification. Production is carried out using fermentation; a process that is important in anaerobic conditions when there is no oxidative phosphorylation to maintain the production of ATP by glycolysis.

ANALGESICS Analgesics are medicines that help to control pain and reduce fever. An analgesic (colloquially known as a painkiller) is any member of the diverse group of drugs used to relieve pain (achieve analgesia). This derives from Greek an-, "without", and -algia, "pain". Examples of analgesics that are available over the counter are: aspirin, acetaminophen, ibuprofen, ketoprofen and naproxen sodium. Some analgesics contain a combination of ingredients in one pill, such as aspirin, acetaminophen and caffeine. Analgesics act in various ways on the peripheral and central nervous system; they include paracetamol (acetaminophen), the nonsteroidal anti-inflammatory drugs (NSAIDs) such as the salicylates, narcotic drugs such as morphine, synthetic drugs with narcotic properties such as tramadol, and various others. Some other classes of drugs not normally considered analgesics are used to treat neuropathic pain syndromes; these include tricyclic antidepressants and anticonvulsants.

Thus acetylsalicylic acid (commonly known as aspirin) is a salicylate with the chemical structure:

Aspirin is commercially synthesized using a two-step process. First, phenol (generally extracted from coal tar) is treated with a sodium base generating sodium phenoxide, which is then reacted with carbon dioxide under high temperature and pressure to yield salicylate, which is acidified, yielding salicylic acid. This process is known as the KolbeSchmitt reaction.

ANTISEPTICS Antiseptics are antimicrobial substances that are applied to living tissue/skin to reduce the possibility of infection, sepsis, or putrefaction. They should generally be distinguished from antibiotics that destroy microorganisms within the body, and from disinfectants, which destroy microorganisms found on non-living objects. Some antiseptics are true germicides, capable of destroying microbes (bactericidal), whilst others are bacteriostatic and only prevent or inhibit their growth. Antibacterial are antiseptics that only act against bacteria. Some chemical compounds/groups of chemical substances that are often used as antiseptics are: •

Alcohols Most commonly used is ethanol (60-90%), 1-propanol (60-70%) and 2propanol/isopropanol (70-80%) or mixtures of these alcohols. They are commonly referred to as "surgical alcohol". Used to disinfect the skin before injections are given, often along with iodine (tincture of iodine) or some cationic surfactants (benzalkonium chloride 0.05 - 0.5%, chlorhexidine 0.2 - 4.0% or octenidine dihydrochloride 0.1 - 2.0%).

•

Quaternary ammonium compounds They include the chemicals benzalkonium chloride (BAC), cetyl trimethylammonium bromide (CTMB), cetylpyridinium chloride , cetylpyridinium chloride (C) and benzethonium chloride (BZT). Benzalkonium chloride is used in some pre-operative skin disinfectants (conc. 0.05 - 0.5%) and antiseptic towels. The antimicrobial activity of Quats is inactivated by anionic surfactants, such as soaps. Related disinfectants include chlorhexidine and octenidine.

•

Boric acid Used in suppositories to treat yeast infections of the vagina, in eyewashes, and as an antiviral to shorten the duration of cold sore attacks. Put into creams for burns. Also common in trace amounts in eye solution. Though it is popularly known as an antiseptic, it is in reality only a soothing fluid, and bacteria will flourish comfortably in with it.

•

Chlorhexidine Gluconate A biguanidine derivative, used in concentrations of 0.5 - 4.0% alone or in lower concentrations in combination with other compounds, such as alcohols. Used as a skin antiseptic and to treat inflammation of the gums (gingivitis). The microbicidal action is somewhat slow. Hydrogen peroxide

Used as a 6% (20Vols) solution to clean and deodorise wounds and ulcers. More common 1% or 2% solutions of hydrogen peroxide have been used in household first aid for scrapes, etc. However, even this less potent form is no longer recommended for typical wound care as the strong oxidization causes scar formation and increases healing time. Gentle washing with mild soap and water or rinsing a scrape with sterile saline is a better practice. •

Iodine Usually used in an alcoholic solution (called tincture of iodine) or as Lugol's iodine solution as a pre- and post-operative antiseptic. No longer recommended to disinfect minor wounds because it induces scar tissue formation and increases healing time. Gentle washing with mild soap and water or rinsing a scrape with sterile saline is a better practice. Novel iodine antiseptics containing iodopovidone/PVP-I (an iodophor, complex of povidone, a water-soluble polymer, with triiodide anions I3-, containing about 10% of active iodine, with the commercial name Betadine) are far better tolerated, don't affect wound healing negatively and leave a depot of active iodine, creating the so-called "remanent," or persistent, effect. The great advantage of iodine antiseptics is the widest scope of antimicrobial activity, killing all principle pathogens and given enough time even spores, which are considered to be the most difficult form of microorganisms to be inactivated by disinfectants and antiseptics.

•

Mercurochrome Not recognized as safe and effective by the U.S. Food and Drug istration (FDA) due to concerns about its mercury content. Another obsolete organomercury antiseptics include bis-(fenylmercury) monohydrogenborate .

•

Phenol (carbolic acid) compounds Phenol is germicidal in strong solution, inhibitory in weaker ones. Used as a "scrub" for pre-operative hand cleansing. Used in the form of a powder as an antiseptic baby powder, where it is dusted onto the belly button as it heals. Also used in mouthwashes and throat lozenges, where it has a methadone-like painkilling effect as well as an antiseptic one. Example: T. Other phenolic antiseptics include historically important, but today rarely used (sometimes in dental surgery) thymol, today obsolete hexachlorophene, still used triclosan and sodium 3,5-dibromo-4-hydroxybenzenesulfonate (Dibromol).

•

Sodium chloride Used as a general cleanser. Also used as an antiseptic mouthwash. Only a weak antiseptic effect, due to hyperosmolality of the solution above 0.9%.

•

Sodium hypochlorite Used in the past, diluted, neutralised and combined with potassium permanganate in the Daquin's solution. Nowadays used only as disinfectant.

DISINFECTANTS By the middle of the nineteenth century, post-operative sepsis infection ed for the death of almost half of the patients undergoing major surgery. In 1839 the chemist Justin von Liebig had asserted that sepsis was a kind of combustion caused by exposing moist body tissue to oxygen. It was therefore considered that the best prevention was to keep air away from wounds by means of plasters, collodion or resins. Germ Connection with wound sepsis When, in 1865, Louis Pasteur suggested that decay was caused by living organisms in the air, which on entering matter caused it to ferment, Lister made the connection with wound sepsis. A meticulous researcher and surgeon, Lister recognized the relationship between Pasteur's research and his own. He considered that microbes in the air were likely causing the putrefaction and had to be destroyed before they entered the wound. In the previous year Lister had heard that 'carbolic acid' was being used to treat sewage in Carlise, and that fields treated with the affluent were freed of a parasite causing disease in cattle. Pasteur suggested three methods: filter, heat, or expose them to chemical solutions. The first two were inappropriate in a human wound, so Lister experimented with the third. As the germ theory of disease became more widely accepted, it was realized that infection could be better avoided by preventing bacteria from getting into wounds in the first place. This led to the rise of sterile surgery. Some consider Lister "the father of modern antisepsis." In 1879 Listerine mouthwash was named after him for his work in antisepsis. Also named in his honor is the bacterial genus Listeria, typified by the food-borne pathogen Listeria monocytogenes. The first major development towards modifying basic antimicrobial agents to make them more specialized, more effective, was in 1906 when Bechhold and Ehrlich synthesized the bis-phenols. They found that by linking two phenol rings directly or by mean of an alkaline group, the bactericidal and bacteriostatic effects of the phenols were greatly enhanced. Further work was done on the bis-phenol (During 1931) leading eventually to the synthesis of hexachlorophene. Iodine has also been modified for use as an antiseptic. The Iodine molecules can be added to other substances which have the ability to increase the antimicrobial qualities of the elements, whilst reducing the irritancy of iodine. .

Antiseptics: An agent that inhibits or destroys microorganisms on living tissue including skin, oral cavities and open wounds. Chemical disinfectants: A chemical agent used on inanimate surfaces and objects to destroy infectious fungi, viruses and bacteria but not necessarily their spores. Sporicidal and antiviral agents may be considered a special class of disinfectants. Disinfectants are often categorized as high level, intermediate level, and low level by medically oriented groups based upon their efficacy against various microorganisms. Decontamination: The removal of microorganisms by disinfection or sterilization. Disinfectants: A chemical or physical agent that destroys or removes vegetative forms of harmful microorganisms when applied to a surface. Sanitizing agents: An agent which reduces microbes on inanimate surfaces, the number of all forms of microbial life including fungi, viruses and bacteria. Sporicidal agents: An agent that destroys bacterial and fungal spores when used in sufficient concentration for a specified time. It is expected to kill all vegetative microorganisms. Sterilants: An agent that destroys all forms of microbial life including fungi, viruses and all forms of bacteria and their spores. Sterilants are liquid or vapor-phase agents. Microorganisms differ greatly in their resistance to disinfecting agents. The order of resistance of clinically significant microorganisms to chemical disinfectants from most to least resistant. The resistance of some clinically important microorganisms to chemical disinfectants: 1) Type of Microorganisms

Examples

2) Bacterial spores

Bacillus subtilis and Clostridium sporogenes.

3) Mycobacteria

Mycobacterium tuberculosis.

4) Non lipid-coated viruses

Poliovirus and Rhinovirus.

5) Fungal spores and vegetative molds

Trichophyton, Crytococcus and Candida sp.and yeasts.

6)

Pseudomonas.aeruginosa,

Vegetative bacteria

Staphylococcus aureus and

Salmonella etc. 7) Lipid-coated viruses

Herpes simplex virus, Hepatitis B virus, HIV

Classification of Disinfectants Chemical disinfectant is classified by their chemical type. This includes Aldehydes, alcohol, halogens, and per-oxides, quaternary ammonium compounds and phenolic compounds. General classification of Antiseptics, Disinfectants and Sporicidal Agents. Chemical Entity 1) Aldehydes 2) Alcohol

Classification Sporicidal agents

Examples 2% Gluteraldehyde

General purpose disinfectants, antiseptic, 70% Isopropyl antiviral agents. alcohol 70% Alcohol. 3) Chlorine and Sporicidal agents 0.5% Sod. Sod.hypochlorite hypochlorite 4) Phenolics General purpose disinfectant 500µg per gm chloroxylenol. 5) Ozone Sporicidal agent 8% gas by weight 6) H2O2 Vapor phase sterilant, liquid sporicidal 4µg per gm H2O2 agent, antiseptic vapor 10-25% solution, 3% solution. 7) Substituted Antiseptic agents 0.5% Chlorhexidine Diguanides gluconate. 8) Per-acetic acid Liquid sterilant, vapor phase sterilant 0.2% Per-acetic acid, 1µg per gm per-acetic acid. 9) Ethylene oxide Vapor-phase sterilnt 660µg per gm ethylene oxide. 10) Quaternary General purpose disinfectant, antiseptic 200µg per gm Amm. Benzalkonium compounds chloride 11) β- Propiolactonic Sporicidal agent 100µg per gm βPropiolactone.

Selection of an antiseptic for hand and surgical site disinfection: Hands and surgical sites are disinfected in a hospital setting to reduce the resident flora and to remove transient flora (e.g. – Streptococcus pyogenes and methicillin resistant Staphylococcus aureus and Pseudomonas aeruginosa) that have been implicated in hospital- associated infection. Use of antiseptic to disinfectant hands has been shown to be more effective than soap and water in reducing the counts of bacteria on the skin; repeated antiseptic use further reduces these counts. These principles may be applied to clean room operation in the pharmaceutical industry.

Mechanism of Disinfectant activity

Target

Disinfectants

Cell wall

Formaldehyde, hypochlorite’s and mercurials 1) Cytoplasmic membrane, action on Anilides and hexachlorophene membrane potential 2) Membrane enzymes, action on Hexachlorophene electron transport chain 3) Action on ATP Chlorhexidine and ethylene oxide 4) Action on enzymes with –SH group Ethylene-oxide, Gluteraldehyde, Hydrogen peroxide, hypochlorite’s, Iodine and mercurial’s 5) Action on general membrane Alcohols, Chlorhexidine and quaternary permeability ammonium compounds. 6) Cell contents, general coagulation Chlorhexidine, Aldehydes, Hexachlorphene and quaternary ammonium compounds 7) Ribosome’s Hydrogen peroxide and mercurial’s 8) Nucleic acids Hypochlorite’s 9) Thiol-groups Ethylene oxide, gluteraldehyde, hydrogen peroxide, hypochlorite’s and mercurial’s 10) Amino groups Ethylene oxide, gluteraldehyde and hypochlorite’s 11) General oxidation Ethylene oxide gluteraldehyde and hypochlorite’s

Microbial Resistance to Disinfectants: The development of microbial resistance to disinfectant is less likely, as disinfectants are more powerful biocidal against low population of microorganisms usually not growing

actively, so the selective pressure for the development of resistance is less profound. However, the most frequently isolated microorganism from an environmental monitoring program may be periodically subjected to use dilution testing with the agents used in the disinfection program to confirm their susceptibility.

Neutralizing Agents for common Disinfectant Disinfectant 1) 2) 3) 4) 5)

Alcohols Gluteraldhyde Sodium hypochlorite’s Chlorhexidine Mercuric chloride 6) Quaternaryammonium compounds

Neutralizing Agents Dilution or polysorbate 80 Glycine and Sodium bisulfate Sodium thiosulfate Poltsorbate 80 and lecithins Thioglycolic acid Polysorbate 80 and lecithins

Because a wide range of different materials of construction are used in clean rooms and other controlled areas, each material needs to be evaluated separately to validate the efficacy of a given disinfectant. Typical surfaces to be decontaminated by disinfectants in a Pharmaceutical manufacturing Area. Materials 1) Stainless steel 2) Glass 3) Plastic, Vinyl 4) Plastic, Polycarbonate 5) Lexan(Plexiglas’s) 6) Epoxy-Coated gypsum 7) Fiber glass-Reinforced plastic 8) Terrazzo tiles

Application Work surfaces, filling equipments and tanks. Windows and vessels. Curtains. Insulation coating. Shields. Walls and Ceilings. Wall ing. Floors.

APPLICATIONS OF DISINFECTANTS Disinfectant Alcohols

Uses Ethyl or isopropyl alcohol at 70-80% concentration is a good general purpose disinfectant; not effective against bacterial spores. Phenols Effective against vegetative bacteria, fungi and viruses containing liquids, unpleasant odor. Formaldehyde Concentration of 5-8% formalin is a good disinfectant against vegetative bacteria, spores and viruses; known carcinogen; irritating odor. Quaternary Ammonium Cationic detergents are strongly surfaced active; extremely Compounds effective against lipoviruses; ineffective against bacterial spores; may be neutralized by anionic detergents (i.e. soaps). Chlorine Low concentrations (50-500 ppm) are active against vegetative bacteria and most viruses; higher concentrations (2,500 ppm) are required for bacterial spores; corrosive to metal surfaces; must be prepared fresh; laundry bleach (5.25% chlorine) may be diluted and used as a disinfectant. Recommended for general use; effective against vegetative Iodine bacteria and viruses; less effective against bacterial spores; Wescodyne diluted 1 to 10 is a popular disinfectant for washing hands.

Factors affecting Disinfection The following are six primary variables that influence the efficacy of disinfection: 1) Nature of the item to be disinfected: The rougher the surface, the longer the time required for disinfection.

2) Number of microorganisms present: The number of microorganism present will lengthen the time for effective disinfection to take place. In general, higher numbers of organisms require more time for disinfection.

3) Resistance of microorganisms:

Some microorganisms are more resistant to disinfection than others. The generally accepted order from the most resistance to the least resistant is: bacterial spore, mycobacteria, hydropjillic viruses, fungi, vegetative bacteria, lipid viruses. Disinfecting a spill with a small concentration of bacterial spores will require longer disinfection time than a large concentration of lipid viruses.

4) Type and concentration of disinfectant used: Resistance of microorganisms depends on the type of disinfectant used. A particular microorganism may be more resistant to one type of disinfectant than another. For instance, alcohol (Isopropyl or ethyl) is effective against vegetative bacteria and most lipophilic viruses. Many disinfectants are broad spectrum; that is, effective against all or most forms of microbial life. Some non-broad spectrum disinfectants include phenolics and quaternary ammonium compounds. Some broad spectrum disinfectants include Gluteraldehydes, sodium hypochlorites, and hydrogen peroxides. Alcohols lie somewhere in between these two. The concentration of a particular disinfectant effects disinfection. In most cases, a higher concentration increases microbial killing power and decreases time necessary for disinfection.

However, some disinfectants are not as effective in higher concentrations. Iodophors must be diluted according to the directions on the label; over-diluting or under-diluting may substantially lower the microbial potency. Alcohols used in concentration above 90% are less effective because the water added to dilute the alcohol allows it to penetrate better and reach its target. Optimal concentration range is between 70-90%.

5) Presence of organic material: The presences of organic soiling matter will compromises disinfection. Blood, blood product, bodily fluids and feces contain significant amounts of proteins, and protein will bind and inactivate some disinfectants or slow their action. Therefore, in the presence of large amounts of protein, a higher concentration of disinfectant and longer time will be necessary to achieve maximal disinfection.

6)

Duration of exposure and temperature: Duration of exposure and temperature influences the disinfection process. The longer the duration of exposure, the higher the degree of disinfection achieved. Some disinfectants require a longer time to achieve killing, and some

microorganisms need longer exposures to be killed. Higher temperature increases the killing power of most disinfectants, where lower temperature may slow the killing power of most disinfectants. . General Description of disinfectants used: 1) Incidur: Incidur is a broad spectrum; Microbiocidal action including HIV, Hepatitis B etc.It shows long residual effect with sustained release. It is manufactured by Henkel . It is purposely used for surface disinfection and fumigation.

Range of application:  High risk areas like Operation theatres, Intensive care Unit (ICU), laboratories and drug manufacturing units.  Commonly used for general purpose in laboratories and pharmaceuticals units. Mode of Action:  It interferes with enzymes with –SH groups and Thiol group of proteins.  It is also responsible for general oxidation of cellular components in microbial cells. Recommended concentration and time (According to manufacturer): • According to manufacturer (Henkel ), Incidur is effective at 1% concentration for 1 hour exposure or time.

2) Levermed: Levermed is broad spectrum hand disinfectant. It acts as Bactericidal, Sporicidal, Fungicidal and Virucidal agent. It is manufactured by Universal Healthcare Silvassa. It is marketed by Johnson Diversy. It is purposely used for hand disinfection and laboratory practices. Levermed is ready to use prepared hand disinfectant. Active Ingredients (w/w): • n- popanol………………………50% •

Iso-propyl Alcohol...……………20%

•

Benzalkonium chloride………...0.5%

•

Emollents.

Range of Application: • Industrial Quality Control Laboratories, Research Institutes, Academics, Drug Manufacturing units. Mode of Action: • It generally shows action towards membrane permeability. It coagulates cellular components. Recommended concentration and time (According to manufacturer): • According to manufacturer (Universal Healthcare, Silvassa), Levermed is effective at 10 minutes exposure or time. 3) Oxivir: Oxivir is broad spectrum environmental cleaner & disinfectant. It is oxygen based Bactericidal, Sporicidal, Virucidal, Fungicidal, Yeasticidal. Oxivir is concentrated oxygen based liquid cleaner disinfectant for cleaning and disinfectant of all water resistant surfaces. It is manufactured by Johnson Diversy. It is effective against Bacteria, Fungi, Yeasts, Virus. It is purposely used for Fumigation, Cleaning and disinfecting equipment. It is compatible with metals and surfaces used in hospitals. However, material compatibility on a small and inconspicuous place is recommended before use. Composition: Hydrogen peroxide Alkyl Benzene sulphonic acid Alcohol ethoxylate (C12-15) 3EO Hydroxyethene-1-1-diphosphonic acid 2- butoxyethanol Feature

Advantage

Benefits

Accelarated hydrogen Higher grade disinfectant peroxide Aldehyde free product Cleaner disinfectant Range of Application:

No negative hazards

Broad spectrum Microbial kill

occupational Eco-friendly and friendly

and Single shot product

Time and cost effective

 Oxivir is purposely used in Hospitals, laboratories, Institutes and Drug manufacturing units. Recommended Concentration and time:  According to manufacturer (Johnson Diversy), Oxivir is effective at 2.5% for 5 minute time. Mode of Action:  Oxivir shows action on enzymes with –SH group.  Oxivir also cause general oxidation of cellular components. 4) Virex II 256: Virex II 256 is high level instrument & surface disinfectant Bactericidal, Sporicidal, Virucidal, Fungicidal, Yeasticidal. Virex II 256 is a high level disinfectant of surfaces and critical instruments (which come in with blood stream or normally sterile areas of the body, such as rigid and flexible surgical instruments) in healthcare application. . It is purposely used for Cleaning and disinfecting equipment. It is compatible with metals and surfaces used in hospitals. However, material compatibility on a small and inconspicuous place is recommended before use. Virex II 256 is blue colored liquid disinfectant manufactured by Johnson Diversy. It is effective against Bacteria, Fungi, Yeasts, Virus. Composition:  Didecyl dimethyl ammonium chloride……………………..8.7%  n-alkyl dimethyl benzyl ammonium chloride………………8.19%  Lauryl amine amine oxide  Ethylene diamine tetra acetic acid sodium salt  Sodium biocarbonate

Feature

Advantage

Benefits

N-alkyl dimethyl benzyl Combination of most potent Broad spectrum kill ammonium chloride & Didecyl QAC’s dimethyl ammonium chloride Aldehyde free product

No negative occupational hazard

Eco friendly and friendly

Cleaner and disinfectant

Single shot product

Time and cost effective

Range of Application:  Virex II 256 is purposely used for instruments disinfection. It is also used for surface disinfection. It is also used for washing and other tiled surfaces. It is compatible with most metals and surfaces used in pharmaceuticals units, Laboratories and Research Institute. Recommended Concentration and time:  According to manufacturer (Johnson Diversy), Virex II 256 is effective at 0.4% for 10 minutes time or exposure. Mode of Action:  It causes general cell components coagulations.

ANTACIDS Antacids perform a neutralization reaction, i.e. they buffer gastric acid, raising the pH to reduce acidity in the stomach. When gastric hydrochloric acid reaches the nerves in the gastrointestinal mucosa, they signal pain to the central nervous system. This happens when these nerves are exposed, as in peptic ulcers. The gastric acid may also reach ulcers in the esophagus or the duodenum. Other mechanisms may contribute, such as the effect of aluminum ions inhibiting smooth muscle cell contraction and delaying gastric emptying. Calcium Carbonate CALCIUM CARBONATE is a calcium salt. calcium carbonate, CaCO3, white chemical compound that is the most common nonsiliceous mineral. It occurs in two crystal forms: calcite, which is hexagonal, and aragonite, which is rhombohedral. Calcium carbonate is largely insoluble in water but is quite soluble in water containing dissolved carbon dioxide, combining with it to form the bicarbonate Ca(HCO3)2. Such reactions on limestone (which is mainly composed of calcite) for the formation of stalactites and stalagmites in caves. Iceland spar is a pure form of calcium carbonate and exhibits birefringence, or double refraction. It is used as an antacid to relieve the symptoms of indigestion and heartburn. It is also used to prevent osteoporosis, as a calcium supplement, and to treat high phosphate levels in patients with kidney disease.

Antacids are usually taken after meals and at bedtime, or as directed by your doctor or health care professional. Take your medicine at regular intervals. Do not take your medicine more often than directed. Need to take care before taking this: •constipation •dehydration •high blood calcium levels •kidney disease •stomach bleeding, obstruction, or ulcer •an unusual or allergic reaction to calcium carbonate, other medicines, foods, dyes, or preservatives •pregnant or trying to get pregnant •breast-feeding Interaction with medicines Do not take this medicine with any of the following medications: •ammonium chloride •methenamine This medicine may also interact with the following medications: •antibiotics like ciprofloxacin, tetracycline •captopril •delavirdine •gabapentin •iron supplements •medicines for fungal infections like ketoconazole and itraconazole •medicines for seizures like ethotoin and phenytoin •mycophenolate •quinidine •rosuvastatin •sucralfate •thyroid medicine.

ANTIHISTAMINES A histamine antagonist is an agent which serves to inhibit the release of histamine. The term antihistamine usually refers to the classical H1 receptor blockers. Reversible & competitive H1 receptor antagonists block the binding of histamine to its receptors. These compounds do not influence the formation or release of histamine. [Cromolyn which inhibits the release of histamine from mast cells and is useful in the treatment of asthma.]

Histamine  Basic amine autacoid stored in granules of mast cells and basophils.

 IgE-dependent release  IgE-independent release (C3a and C5a, or drugs (e.g., d-tubocurarine).  Acts as neurotransmitter in histaminergic nerves

Histamine Synthesis

Histamine Receptors  3 Receptors • H1, H2, H3 (H4 suggested)  All receptors G-protein-coupled  Signaling pathway • H1 (PLC - IP3 & DAG) • H2 (AC – cAMP) • H3 (decrease in Ca2+ flux). Physiological Actions of Histamine/Mediating Receptors Action

Receptor

Smooth muscle contraction

H1

Location All smooth muscles

Vasodilatation

H1

Endothelial cells

Increased Vasc. Permeability

H1 (H2?)

Endothelial cells

Cardiac stimulation

H2

Cardiac muscles

Increased gastric secretion

H2

Parietal cells

Pain and itch

H1

Sensory nerve endings

Inhibition of transmitter relay

H3

Nerve ending

Major Pathological Roles  Allergic diseases • allergic rhinitis (hay fever) • Allergic conjunctivitis • urticaria (Triple response) • anaphylactic shock • Allergic angioedema  Drug reactions  Insect bites  Hyper secretion of acid in peptic ulcers. Classification  1st Generation  2nd Generation 1st Generation  Key • Diphenhydramine • Chlorpheniramine • Doxylamine • Hydroxyzine  Characteristics • High lipophilicity, easily enters CNS • Highly sedative • Anti-muscarinic, anti-α-adrenergic, anti-5HT • Some have anti-motion sickness effect • Some have local anaesthetic effect • Generally short-acting

2nd Generation  Key • Desloratadine (loratadine) • Fexofenadine (terfenadine) • Cetirizine • Azelastine  Characteristics • No CNS entry (Low lipophilicity, most ionized; also protein binding) • Non-sedating • No significant autonomic receptor blocking effect • Generally long-acting • Some are cardio toxic Clinical Uses of Antihistamines  Allergy (e.g., any 1st or 2nd generation) • Allergic rhinitis • Allergic conjunctivitis • Urticaria (both acute and chronic) • Allergic angioedema • Anaphylactic shock  Motion sickness (e.g., diphenhydramine)  As hypnotics (e.g., Doxylamine) Adverse Effects of Antihistamines  Sedation (1st gen.)  Dry mouth, blurred vision (1st gen.)  Cardio toxicity: prolongation of QT intervals (early 2nd gen. terfenadine, loratadine)  Drug interaction (many 2nd gen. metabolized via P450)

TRANQUILLISERS Tranquillizers also known as sedatives are man-made drugs, they are usually prescribed by doctors as short-term treatments for depression, anxiety, stress and insomnia (difficulty in sleeping). The most commonly prescribed tranquillizers are from the class of drugs called benzodiazepines (benzos) and are known as minor tranquillizers. There are various benzos and they are usually known by their brand names, a few of the well known products include: • • • • •

Valium the generic name is diazepam. Ativan the generic name is lorazepam. Mogadon the generic name is nitrazepam. On the street they may be called moggies. Normison the generic name is temazepam. On the street they may be called jellies or eggs. Rohypnol the generic name is flunitrazepam. On the street they may be called roofies, rope or the forget-pill.

Drugs of abuse The easy availability of tranquillizers has made them common as drugs of abuse. Some drug abs take tranquillizers to bring them down after using stimulants such as ecstasy or cocaine. Others take them to enhance the effect of alcohol. Temazepam has become a street drug as a substitute for heroin and Rohypnol is the tranquilizer most associated with "date rape" as it has been known to be used to spike drinks. The victim is often unaware that they have been slipped a drug and while under the influence they are vulnerable to sexual abuse and rape. Immediate effects of tranquillizers Tranquillisers calm the down and reduce feelings of agitation and restlessness, they also slow down mental activity and produce drowsiness. Tranquillisers can have a relaxing effect on the muscles. High doses of tranquillizers can make s forgetful, dizzy and can induce sleep.

The effects of tranquillizers can begin after 10-40 minutes and can last for 3-6 hours but this depends greatly on the drug used and the strength prescribed. There is a high risk of accidents when driving or operating machinery when on tranquillizers. Some tranquillizers can cause a temporary loss of short-term memory, and an increase in aggression. If mixed with alcohol or other depressant drugs tranquillizers can be extremely dangerous and can cause a fatal overdose. Long-term effects of taking tranquillizers A low dosage of tranquillizers prescribed for a short period of time is unlikely to pose any greater risk to health. However, if you take tranquillizers regularly a tolerance can develop, so you will need to take more to get the same effect and you may also find you become dependent on them. Therefore it is recommended that tranquillizers are not used for long periods, and should not be taken for more than a 2-4 week period. If you are taking them for insomnia a 2-3 night break from the tranquillizers each week is recommended. After 2-3 weeks of continuous use tranquillizers may become ineffective as sleeping pills and after 4 months ineffective against anxiety. Long term use of tranquillizers can cause depression, memory loss, mental confusion, stomach disorders and aggressive behaviour. The withdrawal effects can be very unpleasant and include sickness, headaches, irritability, anxiety, nausea and in some cases panic attacks.

ANTI FERTILITY DRUGS/ ORAL CONTRACEPTIVE PILLS The combined oral contraceptive pill (CO), often referred to as the birth-control pill or simply "the pill", is a birth control method that includes a combination of an estrogen and progestogen. When taken by mouth every day, these pills inhibit female fertility.

Mechanism of action Combined oral contraceptive pills were developed to prevent ovulation by suppressing the release of gonadotropins. Combined hormonal contraceptives, including COs, inhibit follicular development and prevent ovulation as their primary mechanism of action.

Progestagen negative decreases the pulse frequency of gonadotropin-releasing hormone (GnRH) release by the hypothalamus, which decreases the release of folliclestimulating hormone (FSH) and greatly decreases the release of luteinizing hormone (LH) by the anterior pituitary. Decreased levels of FSH inhibit follicular development, preventing an increase in estradiol levels. Progestagen negative and the lack of estrogen positive on LH release prevent a mid-cycle LH surge. Inhibition of follicular development and the absence of a LH surge prevent ovulation. Estrogen was originally included in oral contraceptives for better cycle control (to stabilize the endometrium and thereby reduce the incidence of breakthrough bleeding), but was also found to inhibit follicular development and help prevent ovulation. Estrogen negative on the anterior pituitary greatly decreases the release of FSH, which inhibits follicular development and helps prevent ovulation. A secondary mechanism of action of all progestagen-containing contraceptives is inhibition of sperm penetration through the cervix into the upper genital tract (uterus and fallopian tubes) by decreasing the amount of and increasing the viscosity of the cervical mucus.

Drug interactions Some drugs reduce the effect of the Pill and can cause breakthrough bleeding, or increased chance of pregnancy. These include drugs such as rifampicin, barbiturates, phenytoin and carbamazepine. In addition cautions are given about broad spectrum antibiotics, such as ampicillin and doxycycline, which may cause problems "by impairing the bacterial flora responsible for recycling ethinylestradiol from the large bowel"