Drug And Polymers Relating To Prostate Biology Essay

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Tamsulosin hydrochloride, a sulfamoylphenethylamine-derivative, alpha -adrenoceptor blocker with improved specificity for the alpha 1A-adrenoceptors of the prostate, and is commonly used to treat BPH ( benign prostatic hyperplasia). Drug molecule is commercially available in a racemic mixture of 2 isomers, and is pharmacologically related to Prazosin, doxazosin and terazosin. Though, distinct these drugs, tamsulosin have a higher affinity for the alpha-1A- adrenergic receptors, which are mostly situated in vascular smooth muscle region. Some pharmacological Studies prove that tamsulosin has about 12 times greater affinity for alpha-1 adrenergic receptors in the prostate than in the aorta, which might result in a reduced frequency of adverse cardiovascular effects.

Mechanism of action (MOA): All alpa-adrenergic blockers produce significant fall of blood pressure in patients with essential hypertension. Tamsulosin is a selective antagonist for alpha-1A and alpha-1B-adrenoceptors in the prostate condition, prostatic capsule, prostatic urethra and bladder neck. At least three distinct alpha1-adrenoceptor subtypes have been identified: α-1A, α-1B and α-1D; their distribution differs between tissue and human organs. Almost 70% of the α1-receptors in human prostate are of the α-1A subtype. Blocking of these receptors causes relaxation of smooth muscles in the prostate and bladder neck, and thus restrict urinary outflow in men.

Absorption: Absorption of tamsulosin HCI from capsules containing 0.4 mg is essentially complete (>90%) following oral administration under fasting conditions.

Toxicity: LD50 = 650 mg/kg (in rats)

Protein binding: About 94%-99%

Biotransformation: Tamsulosin HCI is widely metabolized by cytochrome P450 enzymes in the liver; however, the pharmacokinetic profile of the metabolites in humans has not been well-known.

t1/2: Elimination half life is 5-7 hours.

Route of elimination: Tamsulosin hydrochloride is widely metabolized by the cytochrome P450 enzyme in the liver and less than 10% of the dose was excreted in urine unchanged. Metabolites of tamsulosin hydrochloride undergo wide conjugation to sulfate or glucuronide preceding to renal excretion. On administration of the radiolabeled dose of tamsulosin hydrochloride to 4 healthy volunteers, about 97% of the administered radioactivity was recovered, with urine (76%) representing the primary route of excretion compared to feces (21%) within 168 hours.

Volume of distributions: 16 L [intravenous administration to ten healthy male adults]

Clearance: 2.88 L/h

Table 6: Drug- Drug interactions




Use of Tamsulosin and Alfuzosin Concomitantly may results in additive antihypertensive effects. Generally this therapy is not recommended here.


Metabolism and clearance of tamsulosin may be reduced by CYP3A4/2D6 inhibitor. Changes in adverse effects were monitored in conditions like Cimetidine initiation and change of dose.


Metabolism and clearance of tamsulosin may be reduced by CYP3A4 inhibitor. Changes in adverse effects were monitored in conditions like Clarithromycin initiation and change of dose.


Metabolism and clearance of tamsulosin may be reduced by CYP2D6 inhibitor. Changes in adverse effects were monitored in conditions like Clozapine initiation and change of dose.


Metabolism and clearance of tamsulosin may be reduced by CYP2D6 inhibitor. Changes in adverse effects were monitored in conditions like cocaine initiation and change of dose.


Metabolism and clearance of tamsulosin may be reduced by CYP3A4 inhibitor. Changes in adverse effects were monitored in conditions like Cyclosporine initiation and change of dose .


Metabolism and clearance of tamsulosin may be reduced by CYP3A4/2D6 inhibitor. Changes in adverse effects were monitored in conditions like Isoniazid initiation and change of dose.


Metabolism and clearance of tamsulosin may be reduced by CYP3A4/2D6 inhibitor. Changes in adverse effects were monitored in conditions like Ketoconazole initiation and change of dose.


Metabolism and clearance of tamsulosin may be reduced by CYP3A4 inhibitor. Changes in adverse effects were monitored in conditions like Norfloxacin initiation and change of dose.


Metabolism and clearance of tamsulosin may be reduced by CYP2D6 inhibitor. Changes in adverse effects were monitored in conditions like Pioglitazone initiation and change of dose.


Metabolism and clearance of tamsulosin may be reduced by CYP3A4 inhibitor. Changes in adverse effects were monitored in conditions like Verapamil initiation and change of dose.


Metabolism and clearance of tamsulosin may be reduced by CYP3A4 inhibitor. Changes in adverse effects were monitored in conditions like Tetracycline initiation and change of dose.

Table 7: List of marketed sublingual tablets



Isosorbide Dinitrate







Fentanyl (as citrate)







Subutex 2mg and 8mg SUBLINGUAL TABLETS

Suboxone 2mg and 8mg SUBLINGUAL TABLETS

zolpidem tartrate

Edluar 5mg or 10mg SUBLINGUAL TABLETS



FROM: http/:dailymed.nlm.nih.gov


Official website of the Drug Bank: Tamsulosin hydrochloride (DB00706).


4.2.1 ETHYLCELLULOSE (Raymond et al., 2003)

Nonproprietary Names

BP: Ethylcellulose

PhEur: Ethylcellulosum

USPNF: Ethylcellulose


Aquacoat ECD; Aqualon; E462; Ethocel; Surelease.

Chemical Name and CAS Registry Number

Cellulose ethyl ether [9004-57-3]

Chemical structure

Ethyl cellulose, CAS #: 9004-57-3

Figure 6: Structure of ethyl cellulose

Functional category

Coating agent; flavoring fixative; tablet binder; tablet filler; viscosity increasing agent.

Typical properties

Density : 0.4gm/cm3

Glass transition temperature : 129-1330C

Specific gravity : 1.12-1.15g/cm3

Viscosity : 5-100m Ps(7-100cp)


Ethyl cellulose is practically insoluble in glycerin,propylene glycol and water.ethyl cellulose that contains less than 46.5% of ethoxy group is freely soluble in chloroform,methylacetate,tetrahydrofuran,aromatic hydrocarbons and ethanol.freely soluble in ethanol,ethyl acetate,methanol and toluene.

Drug release through ethyl cellulose coating dosage forms can be controlled by diffusion mechanism and is a function of wall thickness and surface area of coating thickness.

Stability and storage

It is a stable and slightly hygroscopic material, and is chemically resistant to alkalies and some salt solutions.

Ethyl cellulose is stored at a temperature not exceeding 320C in a dry area away from all sources of heat.


Incompatible with paraffin wax and microcrystalline wax.


Ethyl cellulose is manufactured by treating purified cellulose with an alkali solution, followed by ethylation of the alkali cellulose with chloroethane.

Applications in pharmaceutical formulations

Hydrophobic coating agent for tablets and capsules

To modify the release of drug

To mask the unpleasant taste of drug

To improve the stability of formulations

Thickening agent in creams, lotions and gels

In cosmetics and food products

Binder in tablets

Table 8: Uses of ethyl cellulose





Sustained release tablet coating


Tablet coating


Tablet granulation



Non toxic, non allergic, non irritant material

Handling precautions

Ethyl cellulose is combustible, and hence it is important to prevent dust of ethyl cellulose from reaching potentially explosive levels in air also it is irritant to eyes.

4.2.2 Pectin (www.iscanmy food.com)

A. pectin (from greek-pektiko,'' congealed,curdled") is a structural heterropolysaccharide contained in the primary cell wall of terrestrial plants. It was first isolated and described in 1825 by henri braconnot. It is produced commercially as a white to light brown powder, mainly extracted from citrus fruits and is used in food as jelling agent particularly in jams and jellies . It is also used in fillings,sweet ,as a stabilizer in fruit juices and milk drinks and as a source of dietary fiber.

B. Biology

In plant cells, pectin consists of a complex set of polysaccharides that are present in most primary cell walls and particularly abundant in the non-woody parts of terrestrial plants. Pectin is present throughout primary cell walls but also in the middle lamella between plant cells where it helps to bind cells together.

The amount, structure and chemical composition of pectin differs between plants, with in a plant over time and in different parts of a plant. During ripening, pectin is broken down by the enzymes pectinase and pectinesterase; in this process the fruit becomes softer as the middle lamella breaks down and cells become separated from each other. A similar process of cell separation caused by pectin breakdown occurs in the abscission zone of the petioles of deciduous plants at leaf fall.

In human digestion , pectin goes through the small intestine more or less intact .pectin is thus a soluble dietary consumption of pectin has been shown to reduce blood cholesterol levels. The mechanism appears to be an increase of viscosity in the intestinal tract, leading to a reduced absorption of cholesterol from bile or food.

In the large intestine and colon, microorganisms degrade pectin and liberate short-chain fatty acids that have positive influence on health (prebiotic effect)

C .Chemistry

The characteristic structure of pectin is a linear chain of alpha-(1-4)-linked D-galacturonic acid that forms the pectin-back bone, a homo galactturonan. Into this backbone, there are regions where galacturonic acid is replaced by (1-2)-linked L-rhamnose. From the rhamnose residues, sidechains of various neutral sugars branch off. This type of pectin is called rhamnogalacturonan . Up to every 25th galacturonic acid in the main chain is replaced with rhamnose. Some streaches consist of alternating galacturonic acid and rhamnose-"hairy regions", others with lower density of rhamnose-"smooth regions". The neutral sugars are mainly D-galactose,L-arabinose and D-xylose , the types and proportions of neutral sugars varying with the origin of pectin.

Rhamnogalacturonans (RGs) are a group of closely related cell wall pectic polysaccharides that contain a backbone of the repeating disaccharide: 4)-a-D-GalpA-(1,2)-α-L-Rhap-(1,2) . The term rhamnogalecturonan I (RG-I) is typically used to refer to this pectin polysaccharide.

Another structural type of pectin is rhamnogalacturonan II (RG-II), which is a less frequent complex, highly branched polysaccharide.

Isolated pectin has a molecular weight of typically 60-130,000 g/mol, varying with origin and extraction conditions.

In nature, around 80% of carboxyl groups of galactronic acid are esterified with methanol. This proportion is decreased more or less during pectin extraction. The ratio of esterified to non-esterified galacturonic acid determines the behavior of pectin in food applications. This is why pectins are classified as high-VS. Low-ester pectins or in short HM vs. LM- pectins, with more or less than half of all the galacturonic acid esterified.

The non-esterified galacturonic acid units can be either free acids (carboxyl groups) or salts with sodium, potassium or calcium. The salts of partially esterified pectins are called pectinates, if the degree of esterification is below 5% the salts are called pectates, the insoluble acid form, and pectic acid.

Some plants like sugar beet, potatoes and pears contain pectins with acetylated galacturonic acid in addition to methyl esters. Acetylation prevents formation but increases the stabilizing and emulsifying effects of pectin.

Chemical structure


Figure 7: Structure of pectin

D. Sources and production

Apples, quince, plums, gooseberries, oranges and other citrus fruits contain much pectin, while soft fruits like cherries, grapes and strawberries contain little pectin.

Typical levels of pectin in plants are (fresh weight)

Apples, 1-1.5%



Oranges, 0.5-3.5%

Carrot approx. 1.4% citrus peels ,30%

The main raz-materials for pectin production are dried citrus peel or apple pomance, both by-products of juice production.pomance from sugar beet is also used to a small extent.

Applications of pectin in pharmaceutical formulations (www.mdpi.com/journal/molecules.)

1) As an excipients in many different types of dosage forms such as film coating of colon-specific drug delivery systems when mixed with ethyl cellulose.

2) Micro particulate delivery systems for ophthalmic preparations and matrix type transdermal patches.

3) As a high potential hydrophilic polymeric material for controlled release matrix drug delivery systems, but its aqueous solubility contributes to premature and fast release of the drug from these matrices.

4) Depending on the type and structure of the pectin molecule, pectins can gel in various ways. Gelling can be induced by acid or cross-linking with calcium ion or by reaction with alginate. When a pectin solution is titrated with acid , the ionization of carboxylate groups on pectins is repressed causing pectin molecules to no longer repel each other over their entire chains. The pectins can thus associate over a portion of their chains to form acid-pectin gels. Gel forming systems have been investigated widely for sustained drug delivery.

5) A mixture of xyloglucan with pectin resulted in an in situ gel forming system with sustained paracetamol drug delivery in rats.

4.2.3 Povidone (Raymond et al., 2003)

Nonproprietary Names:

BP : Povidone

JP : povidone

ph Eur : povidone

USP : povidone


E1201; Kollidon; plasdone; poly[1-(2-oxo-1-pyrolidinyl )ethylene]; polyvidone; polyvinylpyrrolidone; pvp; 1-vinyl-2-pyrrolidonone polymer.

Chemical name and CAS Registry number

1-Ethenyl-2-pyrrolidinone homopolymer [9003-39-8]

Chemical structure

chemical structure

Figure 8: Structure of polyvinyl pyrrolidone

Functional category:

Disintegrant; dissolution aid; suspending agent; tablet binder.

Typical properties:

Acidity/alkalinity: pH 3.0-7.0 (5%w/v aqueous solution).

Density (bulk) :0.29-0.39g/cm3for plasdone

Density (tapped) : 0.39-0.54g/cm3

Density (true) : 1.180 g/cm3


20 g/s for povidone k-15

16g/s for povidone k-29/32

Melting point:

Softens at 150°c

Moisture content:

Povidone is very hygroscopic, significant amounts of moisture being absorbed at low relative humidities.

Particle size distribution:

Kollidon 25/30: 90%> 50μm, 50%> 100μm, 5%>200 μm

Kollidon 90: 90%> 200μm, 95%> 250μm.


Freely soluble in acids, chloroform, ethanol, ketones, methanol and water; practically insoluble in ether, hydrocarbons and mineral oils. In water, the concentration of a solution is limited only by the viscosity of the resulting solution, which is a function of the k-value.

Viscosity (dynamic):

The viscosity of aqueous povidone solutions depends on both the concentration and the molecular weight of the polymer employed.

Table 9: Dynamic viscosity of 10% w/v aqueous povidone (kollidon) solutions at 20Ì¥0c


Dynamic viscosity(m pa s)











Stability and storage conditions:

Povidone darkens to some extent on heating at 1500 c , with a reduction in aqueous solubility. It is stable to a short cycle of heat exposure around 110-1300c steam sterilization of an aqueous solution does not alter its properties. Aqueous solutions are susceptible to mold growth and consequently require the addition of suitable preservatives.

Povidone may be stored under ordinary conditions without undergoing decomposition or degradation. However, since the powder is hygroscopic. It should be stored in an air tight container in a cool, dry place.


Povidone is compatible in solution with wide range of inorganic salts, natural and synthetic resins, and other chemicals. It forms molecular adducts in solution with sulfathiazole, sodium salicylate, salicylic acid, Phenobarbital, tannin, and other compounds; the efficacy of some preservatives, e.g., thimerosal, may be adversely affected by the formation of complexes with povidone.

Methods of manufacture:

Povidone is manufactured by the Reppe process. Acetylene and formaldehyde are reacted in the presence of a highly active copper acetylide catalyst to form butynediol, which is hydrogenated to butanediol and then cyclodehydrogenated to form butyrolactone. Pyrrolidone is produced by reacting butyrolactone with ammonia. This is followed by a vinylation reaction in which pyrrolidone and acetylene are reacted under pressure. The monomer, vinyl pyrrolidone, is then polymerized in the presence of a combination of catalysts to produce povidone.

Application in pharmaceutical formulation:

1) Povidone solutions are used as binders in wet granulation processes.

2) Povidone is also added to powder blends in the dry form and granulated in situ by the addition of water, alcohol or hydroalcoholic solutions.

3) Povidone is used as a solubilizer in oral and parenteral formulations (to enhance dissolution of poorly soluble drugs from solid-dosage forms)

4) Povidone solution may also used as coating agents.

5) Used as a suspending, stabilizing or viscosity increasing agent in a number of topical and oral suspensions and solutions.

Table 10: Uses of povidone


Concentration (%)

Carrier for drugs


Dispensing agent

Up to 5

Eye drops


Suspending agent

Up to 5

Tablet binder, diluents (or) coating agent



Non-toxic, nonirritant and no sensitization. Temporary acceptable daily intake for povidone has been set by the WHO at up to 25 mg/kg body weight

LD50 (mouse, IP): 12g/kg

Handling precautions;

Observe normal precautions appropriate to the circumstances and quantity of material handled. Eye protection, Gloves and a dust mask are recommended.

4.2.4 β- cyclodextrin (Raymond et al., 2003)

Non proprietary names:

BP: Betadex

PhEur: Beta dexum

USP NF: Beta dex


β- cyclodextrins: beta-cycloamylose; beta-dextrin;cavamax W7 pharma; Cyclo heptaamylose; cyclo heptaglucan; cyclo maltoheptose; Kleptose.

Chemical Name and CAS Registry Number

β- cyclodextrin [7585-39-9]

Empirical formula

β- cyclodextrin C 42H70O35

Chemical structure

C:\Users\sandeep\Desktop\UntitledBETA CYCLODEXTRIN.png

Figure 9: Structure of β-cyclodextrin


Cylcodextrins are cyclic oligosaccharides containing at least sox D-(+)-Glucopyranose units attached by α(1→4) glucoside bonds.

Cyclodextrins occurs as white, practically odourless, fine crystalline powders, having a slightly sweet taste, some derivatives occurs as amorphous powders.

Molecular weight:


Functional category:

Solubilizing agent; stabilizing agent.

Typical Properties:

Compressibility: 21.0-44.0% for β- cyclodextrin

Density (bulk): 0.523g/cm3

(Tapped): 0.754g/cm3

(True): ---

Melting point: 255-265o c

Moisture content: 13.0-15.0% W/W

Particle size distribution: 7.0-45.0μm


β- Cyclodextrin: soluble 1 in 200 parts of propylene glycol, 1 in 50 0f water at 20o c,

1 in 20 at 50o c; practically insoluble in acetone, ethanol(95%) and methylene chloride.

Specific rotation [α]025 : β- cyclodextrin: +162.0o

Surface tension( at 25oc):

β- Cyclodextrin: 71mN/m(71 dynes/cm).


The activity of some anti microbial preservatives in aqueous solution can be reduced in the presence of hydroxyl propyl- β-cyclodextrin.

Method of manufacture:

Cyclodextrin are manufactured by the enzymatic degradation of starch using specialized bacteria. For example, β- cyclodextrin is produced by the action of the enzyme cyclodextrin glucosyl transferase upon starch or a starch hydrolysate. An organic solvent is used to direct the reaction that produces β- cyclodextrin, and to prevent the growth of microorganisms during the enzymatic reaction. The insoluble complex of β- cyclodextrin and organic solvent is separated from the non-cyclic starch, and the organic solvent is removed in vacuo so that less than 1ppm of solvent remains in the β- cyclodextrin. The β- cyclodextrin is then carbon treated and crystallized from water, dried and collected.

Applications in pharmaceutical formulations:

1. β- cyclodextrin used in oral tablet formulations, both in wet granulations and direct compression processes.

2. β- cyclodextrin is considered to be non-toxic when administered orally, and is primarily used in tablet and capsule formulation.

3. β- cyclodextrin (least soluble) is able to form inclusion complexes with a no. of molecules of pharmaceutical interest.

4. β- cyclodextrin is nephrotoxic and should not be used in parenteral formulation.


Essentially non-toxic and non-irritant material.

Severe nephrotoxicity observed by β- cyclodextrin.

No evidence to suggest that cyclodextrins are mutagenic or teratogenic.

Handling precautions:

Cyclodextrins are fine organic powders and should be handled in a well-ventilated environment.

Efforts should be made to limit the generation of dust, which can be explosive.

4.2.5 Hydroxy propylmethyl cellulose (Raymond et al., 2003)


Benecel HPMC; Cellulose hydroxyroylmetyhl ether; E464; HPMC; Methocel ; Metolose; Pharma coat; Spectracel 6; Tylopur.

Non- proprietary Names:

USP and BP: Hypermellosee

JP: Hydroxy propyl metyl cellulose

Ph.Eur: Hyperrmellosum.

Chemical name and CAS registry name:

Cellulose, 2-hydroxypropyl methyl ether [9004-65-3]

Chemical structure

C:\Users\sandeep\Desktop\File Hypromellose.png - Wikipedia, the free encyclopedia_files\Hypromellose.png

Figure 10: Structure of Hydroxypropyl methyl cellulose

Molecular weight:



Odourless, tasteless, white/creamy, white coloured fibrous or granular powder.

Functional category:

Coating agent, film former, rate-controlling polymer for sustained release; stabilizing agent; suspending agent; tablet binder; viscosity increasing agent.

Applications in pharmaceutical technology:

1. Widely used in oral and topical formulations

2. In oral products as tablet binder (2-5%) in film coating and as extended release matrix.

3. High viscosity grades may be used to retard the release of drugs from a matrix at levels

of 10- 80% w/w in tablets and capsules.

4. Used as a suspending and thickening agent in topical solutions, particularly ophthalmic

(0.45- 1% w/w) preparations.

5. Also used as an emulsifier, suspending agent and stabilizing agent in topical gels

and ointments.

6. Used in manufacture of capsules as an adhesive in plastic bandages and as a wetting agent for hard contact lenses.

Typical properties:


Soluble in cold water but insoluble in chloroform, ethanol(95%) and ether, but soluble in a mixture of ethanol and dichloromethane, mixture of methanol and CH2Cl2, mixture of water and alcohol.

PH: 5.5- 8 for 1% w/w aqueous solution.

Melting point:

Browns at 190-200oc; chars at 225-230o c.

Glass transition temperature; 170-180oc


Tapped: 0.557g/cc

Bulk: 0.341g/cc

Stability and storage conditions:

It is stable material although it is hygroscopic after drying. It should be stored in a well closed container, in a cool and dry place.


With oxidizing agents


Non-toxic and non-irritant material although excessive oral consumption may have a laxative effect.

Table 11: Methocel Application Grid:



Grades used

Bulk laxatives

High viscosity grades of methocel K premium can be used effectively for their water retention property


Creams , Gels and ointments

Good lubricity at low concentrations, good solution clarity.


Opthalmic preparations

Good lubricity at low concentrations, good solution clarity



Efficient thickening, good suspension of solids



Good microbial resistance, good suspension of solids

A15C, A4M,K4M,K15M,F4M


Good microbial resistance, good suspension of solids


Film former

Clarity, adhesion, tensile strength