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Thursday, September 8, 2011

estimation of multi-component formulations

Spectrophotometric multi-component analysis

Absorption spectroscopy is one of the most useful and widely used tools available to the analyte for quantitative analysis. The relation between the concentration of analyte and the amount of light absorbed is the basis of most analytical applications of molecular spectroscopy.  This method of analysis is gaining importance due to simple, rapid, precise, highly accurate and less time consuming. Spectrophotometric multi-component analysis can be applied where the spectra of drugs overlaps. In such cases of overlapping spectra, simultaneous equation can be framed to obtain the concentration of individual component; otherwise multi-component analysis can be applied on any degree of spectral overlap provided that two or more spectra are not similar exactly. Some examples are listed in table-2.
The various spectroscopic techniques used for multi-component analysis are as follows
  • Simultaneous equation method (Vierodt’s method) 3

Concentration of several components present in the same mixture can be determined by solving a set of simultaneous equation even if their spectra overlap. If Beer’s law is followed, these equations are linier.
  • Two wavelength method3

The method can be used to calculate the concentration of component of interest found in a mixture containing it along some unwanted interfering component. The absorption different between two points on the mixture spectra is directly proportional to the concentration of the component to be determined irrespective of the interfering component.
  • The absorption ratio method3

The absorbance ratio method is a modification of the simultaneous equation procedure. It depends on the property that for a substance, which obeys Beer’s law at all wavelength, the ratio of absorbance at any two wavelengths is constant value independent of concentration or path length. e.g. Two dilutions of the same substance give the same absorbance ratio A1 / A2. In the USP, this ratio is referred to as Q value. In the quantitative assay of two components in admixture by the absorbance ratio method, absorbances are measured at two wavelengths. One being the λ max of one of the components (λ2) and the other being a wavelength of equal absorptivity of the two components (λ1), i.e., an iso-absorptive point.  
  • Geometric correction method3

A number of the mathematical correction procedures have been developed which reduce or eliminate the background irrelevant absorption that may be present in the samples of biological origin. The simplest of this procedure is the three-point geometric procedure, which may be applied if the irrelevant absorption is linier at the three wavelengths selected. This procedure is simply algebraic calculations of what the baseline technique in infrared spectrophotometry dose graphically.
  • Absorption factor method (Absorption correction method) 3

It is further modification of simultaneous equation method. Quantitative determination of one drug is carried out by E (1%, 1 cm) value and quantitation of another drug is carried out by subtraction absorption due to interfering drug using absorption factors.
  • Orthogonal polynomial method3

The technique of orthogonal polynomials is another mathematical correction procedure, which involves complex calculation than the three-point correction procedure. The basis of the method is that an absorption spectrum may be represented in terms of orthogonal functions.
  • Difference spectrophotometry3

Difference spectrophotometry provides a sensitive method for detecting small changes in the environment of a chromophore or it can be used to demonstrate ionization of a chromophore leading to identification and quantitation of various components in mixture. The essential feature of difference spectrophotometric assay is that the measured value is the difference absorbance (∆A) between two equimolar solutions of the analyte in different chemical forms, which exhibits different spectral characteristics.
  • Derivative spectrophotometry3

Derivative spectrophotometry is useful means of resolving two overlapping spectra and eliminating matrix interference due to an indistinct shoulder on side of an absorption bands. It involves conversion of normal spectrum [A= f (λ)]to its first [dA/ dλ = f (λ)], second [d2A/ dλ2 = f (λ)]and higher derivatives spectra where the amplitude in the derivative spectrum is proportional to the concentration of the analyte provided that Beer’s law is obeyed by the fundamental spectrum.
  • Area under curve method4

In this method, the absorptivity values (ε1 and ε2) of each of the two drugs were determined at the selected wavelength range. Total area under curve of a mixture at wavelength range is equal to the sum of area under the individual component at that wavelength range. This method is applicable when the λ max of the two components are reasonably dissimilar, the two components do not interact chemically and both the component must be soluble in same solvent.
The methods deviated when overlapping of UV spectra of two drugs significantly and large difference in labeled strength5. e. g. Tizanidine HCl 3.0 mg and nimesulide 100.0 mg per tablet. The accuracy of the method depends upon nature of solvent, pH of solution, temperature, high electrolyte concentration and the presence of interfering substances.

High performance liquid chromatography (HPLC):

This technique is based on the same method of separation as classical column chromatography. i.e. adsorption, partition, ion exchange and gel permeation but it differ from column chromatography, in that mobile phase is pumped through the packed column under high pressure. The technique is most widely used for all the analytical separation technique due to its sensitivity, its ready adaptability to accumulate quantitative determinations, its suitability for separating nonvolatile species or thermally fragile ones. In normal HPLC, polar solids such as silica gel; alumina (Al2O3) or porous glass beads and non-polar mobile phase such as heptane, octane or chloroform are used but if the opposite case holds, it is called as reversed phase HPLC. Some examples are listed in table-3 and 4

High performance thin layer chromatography (HPTLC):

The principle is based on plane chromatography. The mobile phase normally is driven by capillary action. The prominent advantages of this technique includes possibilities of separating of up to 70 samples and standard simultaneously on a single plate leading to high throughout, low cost analogs and the ability to construct calibration curves from standard chromatography under the same condition as the sample. Analyzing a sample by use of multiple separation steps and static post chromatographic detection procedures with various universal and specific visualization regents that are possible because all the sample components are stored on the layer without the chance of loss. Some examples are listed in table-5.

Gas chromatography (GC):

GC is one of the most extensively used separation technique in which separation is accomplished by partitioning solute between a mobile gas phase and stationary phase, either liquid or solid. The chief requirement is same degrees of stability at the temperature necessary to maintain the substance in gas state. Some examples are listed in table-6.

Validation of methods6:

Validation by definition is an act of providing that any process, method, equipment, material, activity, system or analyst performs as expected under given set of conditions. When extended to an analytical procedure, depending upon the application it means that a method works reproducibility when carried out by a same or different person, in same or different laboratories, using different regent, different equipment etc. It will ensure commitment to quality of products and services. It builds a degree of confidence not only for the developer but also to the user.
Validation of analytical method should follow a well documented procedure beginning with the definition of the scope of the method and its validation criteria and including the compounds and matrices, desired detection and quantitation limits and any other important performance criteria. The scope of method should include different equipment and locations where the method will be run. The methods were validated in terms of linearity, accuracy, precision, specificity and reproducibility of sample applications. Analytical method validation has been performed according to ICH guidelines. Accuracy of the method is certain on the basis of recovery studies performed by the standard addition method. The formula used for calculating recovery of pure drug is
Percentage recovery =  T  - A X 100 / S
Where T = Total amount of drug estimated
A= Amount contributed by formulation 
S = Amount of pure drug added.
Precision of analytical method is expressed as SD and RSD of series of measurement by replicate estimation of drug.
The stability indicating ability of the method has been investigated by deliberately degrading the sample preparation. The stress conditions applied are acidic (0.1 M HCl), alkalis (0.1M NaOH) and mild oxidizing condition (3% H2O2) for 24 hr at 50 C. Also heat (60C) and U.V. exposure for 24 hr will be carried out on the sample.
The linearity of the method was investigated by serially diluting the stock solutions of drugs and measured values.
Ruggedness studies has been carried out for different parameters i.e. days and analysts. The results shall be compared with the method.

Wednesday, September 7, 2011

Biopharmaceutical Classification Of Drugs

Biopharmaceutical Classification System:


The biopharmaceutical classification system was developed primarily in the context of immediate release (IR) solid oral dosage forms. It is the scientific framework for classifying drug substances based on their aqueous solubility and intestinal permeability (2). It is a drug development tool that allows estimation of the contributions of three major factors, dissolution, solubility and intestinal permeability that affect oral drug absorption from immediate release solid oral dosage forms. The interest in this classification system is largely because of its application in early drug development and then in the management of product change through its life cycle. It was first introduced into regulatory decision-making process in the guidance document on Immediate Release Solid Oral Dosage Forms: Scale Up And Post Approval Changes (3).
Classification:
According to BCS, drug substances are classified as (Figure 3):
Class I : High Solubility – High Permeability
Class II : Low Solubility – High Permeability
Class III: High Solubility – Low Permeability
Class IV: Low Solubility – Low Permeability
Combined with the dissolution, the BCS takes into account the three major factors governing bioavailability viz. dissolution, solubility and permeability.
This classification is associated with drug dissolution and absorption model, which identifies the key parameters controlling drug absorption as a set of dimensionless numbers viz.
Absorption number, defined as the ratio of the mean residence time to mean absorption time.
Dissolution number, defined as the ratio of mean residence time to mean dissolution time.
Dose number, defined as the mass divided by the product of uptake volume (250 ml) and solubility of drug (4).
Class I drugs exhibit a high absorption number and a high dissolution number. The rate limiting step is drug dissolution and if dissolution is very rapid then gastric emptying rate becomes the rate determining step. e.g. Metoprolol, Diltiazem, Verapamil, Propranolol.
Class II drugs have a high absorption number but a low dissolution number. In vivo drug dissolution is then a rate limiting step for absorption except at a very high dose number. The absorption for class II drugs is usually slower than class II and occurs over a longer period of time. In vitro- In vivo correlation (IVIVC) is usually excepted for class I and class II drugs. e.g. Phenytoin, Danazol, Ketoconazole, Mefenamic acid, Nifedinpine.
For Class III drugs, permeability is rate limiting step for drug absorption. These drugs exhibit a high variation in the rate and extent of drug absorption. Since the dissolution is rapid, the variation is attributable to alteration of physiology and membrane permeability rather than the dosage form factors. e.g. Cimetidine, Acyclovir, Neomycin B, Captopril.
Class IV drugs exhibit a lot of problems for effective oral administration. Fortunately, extreme examples of class IV compounds are the exception rather than the rule and are rarely developed and reach the market. Nevertheless a number of class IV drugs do exist. e.g. Taxol.
bcs3-Biopharmaceutical Classification Of Drugs.jpg

Applications of BCS in oral drug delivery technology (5):


Once the solubility and permeability characteristics of the drug are known it becomes an easy task for the research scientist to decide upon which drug delivery technology to follow or develop.
The major challenge in development of drug delivery system for class I drugs is to achieve a target release profile associated with a particular pharmcokinetic and/or pharmacodynamic profile. Formulation approaches include both control of release rate and certain physicochemical properties of drugs like pH-solubility profile of drug.
The systems that are developed for class II drugs are based on micronisation, lyophilization, addition of surfactants, formulation as emulsions and microemulsions systems, use of complexing agents like cyclodextrins.
Class III drugs require the technologies that address to fundamental limitations of absolute or regional permeability. Peptides and proteins constitute the part of class III and the technologies handling such materials are on rise now days.
Class IV drugs present a major challenge for development of drug delivery system and the route of choice for administering such drugs is parenteral with the formulation containing solubility enhancers.

Conclusion:

The in vivo performance of the drug depends upon its solubility and permeability. The biopharmaceutical classification system is the guiding tool for the prediction of in vivo performance of the drug substance and development of drug delivery system to suit that performance. The knowledge of the biopharmaceutical class of the drug substance is also essential for biowaivers thereby reducing the cost both in terms of money and time.

References:

1. Draft Guidance for Industry, Waiver of In Vivo Bioavailability and Bioequivalence Studies for Immediate Release Solid Oral Dosage Forms containing certain Active Moieties/ Active Ingredients based on a Biopharmaceutic Classification System, February 1999, CDER/FDA.
2. Amidon G.L., Lennernas H., Shah V.P., Crison J.R.A., A Theoretical Basis For a Biopharmaceutic Drug Classification: The Correlation of In Vitro Drug Product Dissolution and In Vivo Bioavailability. Pharm. Res. 12: 413-420 (1995).
3. Guidance for Industry, Immediate Release Solid Oral Dosage Forms: Scale Up and Post Approval Changes, November 1995, CDER/FDA.
4. Medicamento Generico from website http://www.anvisa.go/.
5. Devane J., Oral drug delivery technology: addressing the solubility/ permeability paradigm, Pharm. Technol. 68-74, November 1998.

Thursday, August 11, 2011

USP Minimum Sample Weight

Minimum sample weight is defined as the minimum sample quantity required by a balance or scale to obtain a reliable result, taking into account factors such as measurement uncertainty. In the pharmaceutical industry, the United States Pharmacopoeia (USP) is widely recognized as the official authority that prescribes the requirements for determining minimum sample weight.

According to USP Chapter <41> Weights and Balances i, measurement uncertainty should satisfy the following requirements:
  1. The measurement uncertainty of a balance or scale does not exceed 0.1% of the reading.
  2. Three times the standard deviation ii, as determined by at least 10 replicate weighings, does not exceed 0.001 (0.1%) when divided by the amount weighed.
The conditions above can be expressed using the following equations:

Resolution
Model
Capacity
Repeatability (σ)
Measurement Uncertainty (3σ)
Minimum Sample Weight
0.01mgGH-20251g (Fine range)0.02mg0.06mg60mg
GR-20242g (Fine range)
0.1mgGH-200220g0.1mg0.3mg300mg
GR-200210g
0.001gGX-200210g0.001g0.003g3g
0.01gGX-20002100g0.01g0.03g30g

Thursday, August 4, 2011

Comparison of Matrix Effects in HPLC-MS/MS

Jet C. Van De Steene and Willy E. Lambert
Laboratory of Toxicology, Ghent University, Ghent, Belgium
When developing an LC-MS/MS-method matrix effects are a major issue. The effect of
co-eluting compounds arising from the matrix can result in signal enhancement or suppression.
During method development much attention should be paid to diminishing matrix
effects as much as possible. The present work evaluates matrix effects from aqueous
environmental samples in the simultaneous analysis of a group of 9 specific pharmaceuticals
with HPLC-ESI/MS/MS and UPLC-ESI/MS/MS: flubendazole, propiconazole, pipamperone,
cinnarizine, ketoconazole, miconazole, rabeprazole, itraconazole and domperidone. When
HPLC-MS/MS is used, matrix effects are substantial and can not be compensated for with
analogue internal standards. For different surface water samples different matrix effects are
found. For accurate quantification the standard addition approach is necessary. Due to the
better resolution and more narrow peaks in UPLC, analytes will co-elute less with interferences
during ionisation, so matrix effects could be lower, or even eliminated. If matrix effects
are eliminated with this technique, the standard addition method for quantification can be
omitted and the overall method will be simplified. Results show that matrix effects are almost
eliminated if internal standards (structural analogues) are used. Instead of the time-consuming
and labour-intensive standard addition method, with UPLC the internal standardization can
be used for quantification and the overall method is substantially simplified. (J Am Soc Mass
Spectrom 2008, 19, 713–718) © 2008 American Society for Mass Spectrometry

Wednesday, January 26, 2011

NIPER question paper 2009



NIPER Question
1. Which is cytotoxic from following marine? (bryostatin)
2. To avoid crystallization of syrup which substance is added? (polyhydric alcohols)
3. Particle size of fluid energy mill is? (1-30micrometer)
4. Use of Gallic acid? (Antioxidant)
5. HLB of o/w emulsion. (3-8)
6. Range of Visible light? (400-800nm options were in micro so read questions carefully
before attaining )
7. Source of IR (Nerst glower)
8. Hydrogen bonding determined by which method? (Raman)
9. Most intense peak in MASS spectra? (Base peak)
10. How to determine non-UV active structure? (derivatization)
11. Energy comparison of UV, IR n NMR. Means put them in ascending order of their energies.
(NMR least<ir
12. Reference standard used in NMR? (TMS)
13. In IR calibration which substance is used? (Air)
14. What does RS means in IP? (Reference standard)
15. Sparingly soluble? (30 to 100 parts)
16. Cough is S/E of? (captopril)
17. Capsule '000' size capacity?
18. Green bones are made up of which type of gelatin? (type B)
19. Vehicle used in SGC?
20. Which property not related to polymorphism? (chemical assay)
21. Ostwald ripening is related with? (suspension)
22. Osmotic pressure of blood is?
23. Duration of nasal delivery
24. Duration of mucoadhesive delivery
25. Largest cotton producing country
26. Free trade port in India? (Kandla)
27. Amoebiasis is caused by? (E.histolytica)
28. In clock 12'o clock is north east then at 1:30pm what would be direction? (East)
29. In monosubstituted cyclohexane which structure will be stable?
30. Stereochemistry of Alanine
31. Linkage in amylase
32. Teratogenic vitamin? (A)
33. In cyclic carbohydrates stereochemistry is known as? (anomer)
34. Propranolol is contraindicated in? (Asthma)
35. Highest first pass metabolism of following?
a. propranolol (ans) b. digoxin c. Phenobarbital d. phenytoin
36. Which of this is cardiotoxic (Adriamycin)
37. M/A of paclitaxol is?
38. Therapeutic index denotes (Margin of safety)
39. Selective ï ¡ 1 blocker is? (Prazosin)
40. Activity of receptor (drug selectivity and selective antagonist action of drug)
41. Receptors are made up of? (protein)
42. Cytokinins are?
43. Morphine act through ï receptor.
44. Nicotinic receptor work through which messenger system?
45. Example of Neurodegenerative disorder. (Alzheimer's Disease)
46. Action of Ach? (Hastens G.I. emptying)
47. Name of Indian Ginseng? (Withania Somnifera)
48. Father of Chemotherapy? (Paul Ehrlich)
49. Out of following which is not containing bacteria?
a. Soil b. Ice c. Dust d. Blood (ans) (blood is sterile unless infected)
50. Drug approved by US FDA for alopecia? (Minoxidil)
51. Drug interaction is hazardous of following? (terfinadin + erythromycin)
52. Which of following cause cardiac arrhythmia? (terfinadin)
53. ï ¢2 selective(salbutamol)
54. Cerebral Malaria (quinine)
55. Which malaria is deadly? (P. falciperum)
56. Use of Primaquine is? (choloroquine resistant P. falciperum)
57. Tamoxifen used in breast cancer act as? (estrogen antagonist)
58. Metallic elements detected by? (AAS)
59. Enthalpy is measure of?
60. Luminescence, fluorescence and phosphorescence is a type of? (Emission spectroscopy)
61. Rate Kinetic deals with? (order, molecularity and conc of reactant)
62. In exothermic process increase in temp indicate what?
a. Reactant is more b. product yield is more(ans) c. Rxn stopped d. equilibrium
63. Cough syrup mostly contains which alkaloid? (Codeine)
64. Terpenoid are obtained from which biosynthetic pathway?
65. In diosgenin which ring is present?
66. In triterpenoid how many isoprene units are present? (6)
67. In dipeptide bond how many amino acids are present? (3)
68. Which of following contain chromosome or DNA?
a. mitochondria (ans) b. ER c. Golgibody d. cytoplasm
69. t-RNA function
70. Inhibition of mammalian gene expression is at the level of?
71. IPEC deals with?
a. Excepient (ans) b. US FDA c. GMP d. GLP (International Pharmaceutical Excipient Council)
72. ABC analysis deals with? (Inventory control)
73. Phase- IV deals with?
74. IND is for? (filling of NCE New Chemical Entity now changed to NME New Molecule Entity as biomolecules are not considered as chemical)
75. Minimum velocity required for laminar air flow unit? (100)
76. Cardiac Ca++ channel blocker? (nifedipine)
77. Ca++ channel use which type of messenger system?
78. Fill in the gap: stu_ _ st _ _ ws _ _ vw (vwuvtu)
79. Which of following is endothermic?
a. Adsorption b. crystallization c. vaporization d. all
80. Betaine structure (Refer Wittig reaction)
81. Structure of nifedipine.
82. Stereochemistry in biphenyl
83. How to determine unsaturation? (bromination,hydrogenation,ozonolysis)
84. NMR signal obtained in 1,4- dioxane (1 peak)
85. Reaction occurring in ethane? (E1 )
86. Tomato red pigment is due to? (Lycopene)
87. Insulin act on which cells? (Beta)
88. PG released by (COX-II)
89. Aspirin is? (Irreversible COX inhibitor)
90. Phenytoin used in? Digitalis induced arrhythmia)
91. Serotonin is neurotransmitter
92. Alcohol dehydrogenase converts (ethanol to acetaldehyde)
93. Major product obtained from purine metabolism is? (Uric acid)
94. Saffron cultivated in (Jammu n Kashmir)
95. Benzyl alcohol 1% is used as Preservative
96. Cetyl ether of Polyethylene glycon is known as? (Cetomacrogol)
97. Detector used in spectrophotometer? (Photo multiplier tube)
98. Living organisms are detected by? (Dark field microscopy)
99. Which of following is not static? (Flash dryer)
100. Rifampicin used not only in TB but also in? (Leprosy)
---------------------------
01. Immunoglobulin is? (2 light, 2 heavy, disulfide)
02. Which of following not causing enzyme induction? (Sulfonamide)
03. Detector used in IR? (Thermocouple)
04. Function of microvilli is? (Increase surface area)
05. pH of 0.005M HCL?
06. pH of pKa 5.4 is?
07. IR range of CO (acid chloride)
08. Neostigmin does not cross BBB? (Polar)
09. Drugs which cross BBB are? (lipophilic drugs)
10. Which is most commonly used HPLC? (Reverse Phase)
11. Phenolphthalein is? (Acid base indicator)
12. Drug assayed by acid-base back titration? (Aspirin)
13. Which of following is titrated using strong base? (Refer IP for titrations, this can be
considered as important)
14. Amiloride and Spiranolactone differs in?
15. Statin mechanism? (Reduce cholesterol)
16. Which of following is not related with enalapril (It is not an AT1 antagonist)
17. Equation of Angle of Repose.
18. Character of liposome is?
19. Eye drops and parentral differ in?
20. Colchicines is used in Gout.
21. Omeprazole act by?
22. Muscarinic antagonist used in ulcer.
23. Most commonly used in PD? (L-dopa)
24. Dopamine agonist used in PD. (Bromocryptine)
25. Which of this is not acting on nuclear receptor? (Amino acid trypsin)
26. Nucleus present in coumarin.
27. Which of following is used in vascular disorder? (Ginko biloba)
28. Podophyllotoxin is? (Lignan)
29. Bacterial cell wall consists of? (Heteropolysaccharide)
30. In indole biosynthesis which AA is used? (Typtophan)
31. Sugar in protein preparation act as? (cryoprotective)
32. Non aq. Binder
33. Flow of genetic information (DNA to RNA to Protein)
34. Iodine Value
35. SDS-PAGE is used for? (Protein)
36. Yield calculation of synthesis.
37. Thermal assay (DSC)
38. Auxochrome function.
39. Supreme commander? (President)
40. Vant Hoff equation
41. Nitrites? (Vasodilation)
42. CH3 F (deshielded so downfield)
43. Expiry date determined by use of drug along with container.
44. Which is most permeable to moisture? (Polyethylene)
45. Accelerated stability study is done at what temp n RH?
46. Dose required for intradermal delivery.
47. Aim of welfare state.
48. Solubilsation is based on (Stereochemistry)
49. Circular diachronism spectroscopy is used for? (Optically active compound)
50. Simple and compound interest calculation.
51. Digitalis acts by Na+ / K+ ATPase Pump
52. Syphilis is caused by?
53. Acetazolamide? (Carbonic anhydrase inhibitor)
54. Unit of delta(ppm)
56. HIV is caused by? (Virus)
Apart from this is contains many mathematical calculations, synonyms, antonyms and acronyms.

(And same paper is their for MBA and MS)

Note: In form they provide one option for sponsor seat do tick that option it do not require any industrial recommendation but it is one sort of payment seat. If you don't tick that option you will not be eligible for taking admission in payment seat.

Few useful acronyms.
1. CPCSEA- Committee for Purpose of Control and Supervision of Experimental Animals.
2. IAEC- Institutional Animal Ethics Committee
3. BEA-Breeding for Experimental Animals
4. SDS-PAGESodium Dodecyl Sulfate- Polyacrylamide Gel Electrophoresis
5. NME- New Molecular Entity
6. NCE- New Chemical Entity
7. GRAS- Generally Accepted As Safe
8. ANDA- Abbrevated New Drug Application (Generic filling)
9. IIG- Inactive Ingredient Guide

Note: Answers given in bracket is best of the options given. It might not be the most appropriate answer for that question. And don't rely on answer completely we have wrote what we were able to remember so please do check textbooks.

NIPER JEE 2005

flow injection system in HPLC?
fingerpoint region in IR?
trance stilbens?
alfa and beta d-glucose structure?
most suitable diluent for controlled releae/
solvents in reverse phase chromatography?
RNA and DNA str?
reverse transcriptase enzyme?
chloroquin used in ..?
artemisin ?
asparginase?
kaalfischer titration?
alkaloid which is not therapeutical active?
configuration of ephedrine/
endogenous anticoagulant?
Sulfonylureas?
what happend in type 2 daibetes?
afficacy and affinity?
What is nitric oxide?
type of Ca++ present in heart?
Action of dopimine?
antagonist of levodopa?
First law of thermodinamicss/
cubic nature of NACl?
mechanism of adaptogen/
NMR
UV calculation
mass calculation of fragments?
rimer-timen reaction.
Find distereomers?
route of administration?
gingival hyperplasia is a side effect of?
isoprene unit of FPP?
analytical technique of noble druges?
stop codon?</ir

Wednesday, January 12, 2011

effect of cancer chemotherapy on reproduction and sexuality

Reproduction and sexuality
Reproductive and sexual problems can occur after you receive chemotherapy. Which, if any, problems develop depends on your age when you are treated, the dose and duration of the chemotherapy, and which chemotherapy drugs are given.

Sexual changes men may experience

Most men on chemotherapy still have normal erections. A few, however, may develop problems. Erections and sexual desire often decrease just after a course of chemotherapy, but usually recover in a week or two. A few chemotherapy drugs, for example cisplatin or vincristine, can permanently damage parts of the nervous system. Although it is not yet proven, these drugs may interfere with the nerves that control erection.
Chemotherapy can sometimes affect sexual desire and erections by decreasing the amount of testosterone produced. Some of the drugs used to prevent nausea during chemotherapy can also upset a man's hormone balance, but hormone levels should return to normal after treatments have ended.
Many chemotherapy drugs can affect sperm and the parts of the body that produce them. Some of these effects may be permanent. Freezing sperm before chemotherapy begins is one option for men who wish to father children later in life. (If you would like to read more about this, see our document called Fertility and Cancer: What Are My Options?)
Although it is sometimes possible to father children during chemotherapy, the toxicity of some drugs may cause birth defects. Because of this, it is suggested that all men getting chemotherapy take precautions and use a reliable type of birth control if they are sexually active.
Chemotherapy may suppress your immune system. If you have had genital herpes or genital wart infections in the past, you may have flare-ups during chemotherapy.
Chemotherapy is often given through an IV tube into the bloodstream. However, new ways have been developed to get drugs directly to a tumor. For cancer of the bladder, for example, chemotherapy is placed right into the bladder through a catheter in the urethra. Such a treatment has only a minor effect on a man's sex life. You may notice some pain if you have sex too soon after the treatment. This is because the bladder and urethra are still irritated.
For more information, please see our document Sexuality for the Man With Cancer.

Sexual changes women may experience

Many chemotherapy drugs can either temporarily or permanently damage a woman's ovaries, reducing their output of hormones. This affects a woman's fertility and libido (sex drive). Ovarian function is less likely to return in women over age 30, so they are more likely to go into menopause. (If you would like to read more about preserving fertility, see our document called Fertility and Cancer: What Are My Options?) Symptoms of early menopause include hot flashes, vaginal dryness and tightness during intercourse, and irregular or no menstrual periods. As the lining of the vagina thins, light spotting of blood after intercourse becomes common.
Even though menstrual cycles may be disrupted or stopped with chemotherapy, it may still be possible to get pregnant at this time. The toxicity of some chemotherapy drugs may cause birth defects. Because of this, women getting chemotherapy should take precautions and use a reliable type of birth control if they are sexually active.
Some chemotherapy drugs irritate all mucous membranes in the body. This includes the lining of the vagina, which often becomes dry and inflamed (a condition called vaginitis).
Vaginal infections are common during chemotherapy, particularly in women taking steroids or powerful antibiotics used to prevent bacterial infections. Yeast cells are a natural part of the vagina's cleansing system. If too many grow, however, you may notice itching inside your vagina, a whitish discharge that often looks like cottage cheese, or a burning sensation during intercourse. Yeast infections can sometimes be prevented by not wearing pantyhose, nylon panties, or tight pants. Loose clothing and cotton panties allow better air circulation. Your doctor may also recommend a vaginal cream or suppository to reduce yeast cells or other organisms that grow in the vagina. Most of these medicines can be bought without a prescription, although there are treatments that can be taken by mouth that must be prescribed by a doctor. It is very important to have vaginal infections treated if you are getting chemotherapy. Your body's immune system is not as strong because of the treatment, and any infection may become a more serious problem if it is not dealt with as early as possible.
If you have had genital herpes or genital wart infections in the past, you may have flare-ups during chemotherapy. This is because the chemotherapy suppresses your immune system.
Chemotherapy is often given through an IV tube into the bloodstream. However, new ways have been developed to bring drugs directly to a tumor. For cancer of the bladder, for example, chemotherapy is placed right into the bladder through a catheter in the urethra. Such a treatment usually has only a minor effect on a woman's sex life. You may notice some pain if you have sex too soon after the treatment. This is because the bladder and urethra are still irritated