MIDTERM-QUIZ 2 Flashcards
• used to prevent microbial contamination
• Ideal Characteristics: effective at low concentrations against all possible
microorganisms, nontoxic, compatible with other constituents used in the
preparation, stable for the shelf-life of the preparation
Preservative
• p-hydroxybenzoic acid
• useful as preservative for liquid dosage forms
• have antifungal properties
• preservative effect tends to increase with molecular weight
• can cause irritation for sensitive skin
Parabens
• more effective against molds
Methylparaben
• more effective against yeasts
• more oil-soluble so it is preferred for oils and fats
Propylparaben
10 Other Preservatives
- Chlorobutanol
- Benzyl Alcohol
- Phenylethyl Alcohol
- Benzoic Acid
- Sodium Benzoate
- Sodium Propionate
- Sorbic Acid
- Potassium Sorbate
- Phenylmercuric Nitrate
- Phenylmercuric Acetate
• occurs naturally in rose oil and pine-needle oil
• used primarily in perfumery
Phenylethyl Alcohol
• used externally as an antiseptic for lotions, ointments and mouthwashes; more
• effective as a preservative in foods and pharmaceutical products at low pH
Benzoic Acid
• used as preservative in acidic liquid preparations in which benzoic acid is
releases
Sodium Benzoate
• effective antifungal that is used as preservative
Sodium Propionate
• an effective antifungal preservative
• used to preserve syrups, elixirs, ointments, and lotions containing components such as sugars that support mold growth
Sorbic Acid
• used as the same way as sorbic acid
Potassium Sorbate
• used to preserve injectable drugs but bacteriostatic efficacy is reduced in the presence of serum
Phenylmercuric Nitrate
• used as preservative
Phenylmercuric Acetate
• Acid fast bacteria
• Rod shaped, aerobic bacteria that does not form spores
• facultative intracellular, obligate aerobe
• causes Koch’s disease
• Lowenstein-Jensen medium (serpentine growth colonies)
Mycobacterium tuberculosis
• Isonicotinic acid hydrazide
• Nydrazid®
• MOA: inhibits the synthesis of mycolic acid, an important component of the cell wall of mycobacteria
• Principal adverse effect: Peripheral neuritis due to the competition of INH with pyridoxal phosphate for the enzyme apotryptophanase
• co-administration of pyridoxine prevents peripheral neuritis
Isoniazid (INH or H)
• Trecator SC®
• structural analogue of isoniazid
• used in the treatment of isoniazid-resistant tuberculosis
• S/E: GI irritation, hepatotoxicity, peripheral neuropathies, optic neuritis
Ethionamide
• Pyrazinecarboxamide
• MOA: unknown
• used in combination with other agents because resistance develops rapidly
• S/E: hepatotoxicity (inc. ALT/AST)
• must be enzymatically hydrolyzed to pyrazinoic acid (active form)
Pyrazinamide (PZA or Z)
• Myambutol®
• S/E: Optic neuritis
• loss of ability to discriminate between red and green
• MOA: inhibits the incorporation of mycolic acids in the cell walls of the bacteria
Ethambutol (EMB or E)
• MOA: acts as a competitive inhibitor for p-aminobenzoic acid (PABA) in folate biosynthesis
• S/E: severe gastric irritation
• second-line treatment for TB
Para-Aminosalicylic Acid (PASA/PAS)
• Lamprene®
• MOA: unkwown
• basic red-dye used in the treatment of leprosy, including dapsone-resistant forms
• S/E: Colored-maroon urine
Clofazimine
• obtained from Streptomyces mediterranei
• includes Rifampin and Rifabutin
Rifamycin
• Rifadin, Rimactane, Rifampicin
• the most active agent against TB
• enzyme INDUCER toxic effects are relatively infrequent
• when it is taken in combination with INH or ethambutol, incidence of HEPATOTOXICITY is significantly higher
• S/E: reddish color of body secretions, hepatotoxicity
Rifampin
First Line Treatment for TB
• Rifampin
• Isoniazid
• Pyrazinamide
• Ethambutol
• Streptomycin
PTB = 2 mos (RIPE w/ or w/o S)
4 mos - maintenance phase (R + I)
First Line Treatment for TB
• Seromycin®
• isolated from different species of Streptomyces: S. orchidaceus, S. garyphalus, S. lavendulus
• MOA: prevents the synthesis of cross-linking peptide in the formation of bacterial cell walls
Cycloserine
• isolated from Streptomyces capreolus
Capreomycin
• only aminoglycosides used for tuberculosis
• the first antibiotic effective in the treatment of TB (1944 by Waksman)
Streptomycin
• study of fungi
Mycology
• studied Trichophyton schoenleinii (1839)
Schonlein & Gruby
• reported the yeast- like microorganism responsible for oral thrush (Candida albicans)
Langenbeck
2 Groups of Fungal Infections
• Superficial mycoses
• Deep-seated mycoses
• most common
• caused by dermatophytes
• includes tinea or ringworm infections and Candida infections
Superficial Mycoses
8 Causative agents of Ringworm Infections
- Tinea capitis
- Tinea barbae
- Tinea faceie
- Tinea cruris
- Tinea pedis
- Tinea manum
- Tinea ungium (Onchomycosis)
- Pityriasis versicolor
8 Systemic Mycoses
- Histoplasmosis
- Sporotrichosis
- Blastomycosis
- Coccidioidomycosis
- Cryptococcosis
- Paracoccidioidomycosis
Cutaneous Infections (Dermatophytoses)
- Microsporum
- Trichophyton
- Epidermophyton
- Malassezia furfur
• refers to a group of fungal diseases in which both the skin and subcutaneous
tissue are involved but typically no dissemination to the internal organ occurs
Subcutaneous Fungal Infections
• tinea or ringworm
Dermatophytoses
• acidic, fatty substance in and on the skin; functions as a natural antifungal agent and part of the innate immune system
Sebum
• an antifungal agent that is non-irritating and nontoxic
Propionic Acid
• unstable to moisture, forming zinc hydroxide and propionic acid
• used as fungicide, particularly on adhesive tape
Zinc Propionate
• used topically to treat superficial dermatomycoses caused by C. albicans and Trichophyton, Epidermophyton and Microsporum spp.
• from caprylic acid found in coconut or palm oil
Sodium Caprylate
• 10-Undecenoic acid
• obtained from the destructive distillation of castor oil
• can be used in concentrations up to 10%
• traditionally used for athlete’s foot
Undecylenic Acid
• activity is due to acetic acid released by hydrolysis of the
compound by esterases present in the skin
Triacetin
• has both antiseptic and keratolytic properties
• a poor antifungal agent
Salicylic Acid
• contains 6% benzoic acid and 6% salicylic acid in a petrolatum base
• benzoic acid cannot penetrate the outer layer of the skin in infected areas thus used with keratolytic agents
Whitfield’s Ointment
• used as a 1% cream for the treatment of superficial tinea infections
• lesion typically worsens before it improves
• iflammation and painful irritation are common
Haloprogin
• Vioform®
• 3% ointment or cream is used as a treatment for Trichomonas vaginalis (Vaginitis)
• Vioform HC® - combination with hydrocortisone
Clioquinol
• an agent of choice for cutaneous candidiasis, tinea corporis, tinea cruris, tinea pedis and tinea versicolor
• second-line treatment for onychomycosis
• MOA: at low concentrations, it blocks transport of amino acids into the cells; at high concentrations, membrane integrity is lost and cellular contents leak out
Ciclopirox Olamine
• Ancobon®
• used only in combination with Amphotericin B for the treatment of systemic mycoses and meningitis caused by Cryptococcus neoformans and Candida
(Synergistic)
• MOA: release 5-FU
Flucytosine
3 Polyenes
- Amphotericin B
- Nystatin
- Natamycin
• Fungizone®
• naturally occuring, produced by Streptomyces nodosus
• MOA: binds to ERGOSTEROL present in the cell membrane disrupting membrane function, allowing electrolytes to leak out from the cell, resulting in cell death
• drug choice for systemic mycoses (disseminated forms of coccidioidomycosis, North American blastomycosis, cryptococcosis, histoplasmosis, mucormycosis, aspergillosis and sporotrichosis)
• S/E: Renal toxicity, acute febrile reaction, anemia, phlebitis
Amphotericin B
• Mycostatin®
• first isolated from a strain of Streptomyces noursei
• used for the treatment of Candida (Monilial) infections
• administered as an oral agent for the treatment of oral candidiasis
• not absorbed systemically when administered orally
• swish and swallow
Nystatin
• Natacyn®
• obtained from Streptomyces natalensis
• fungicidal and fungistatic at the same concentration range
• supplied as 5% ophthalmic suspension intended for the treatment of fungal conjunctivitis, blepharitis, and keratitis
Natamycin
3 Other Antifungal Antibiotics
• Griseofulvin (Grifulvin®
• Grisactin®
• Gris-PEG®)
4 Opportunistic Fungal Infections
- Systemic candidiasis
- Aspergillosis
- Mucormycosis
- Pneumocystis carinii
