Topical Agents PDF

roplc'1A;,.ge_n_t._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ____:z=Z3 ::.;:.--- h' ' t Assay, T 1sf o1~ ment is assayed by transferring its about 5 g to a stopped flask which is already having 25 rnl o sohtnt :her, 15 ml of petroleum ether, 2 g of potassium iodide and 50 ml of water. It...

roplc'1A;,.ge_n_t._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ____:z=Z3 ::.;:.--- h' ' t Assay, T 1sf o1~ ment is assayed by transferring its about 5 g to a stopped flask which is already having 25 rnl o sohtnt :her, 15 ml of petroleum ether, 2 g of potassium iodide and 50 ml of water. It ! is shaken thdorolukgl' at~ then kept undisturbed for half an hour and shaken frequently in between. }'berate a a 1 1s 1trated with o1 N HCl. '. The 1 · emp1oy1ng methyl orange as an indicator. Each ml of 0.1 N HCl 0,01261 g of NH HgC1. 2 Uses, It has been used in a similar manner as ammoniated mercury. rOF.NTS.. (E.'_ese ar~ the _compounds which bnng about protein precipitation. They are usually applied to. damaged skin topic~lly or to the mucous membrane of the GIT including the mouth. The precipitated protein and the astringent form a protective layer on the surface. oue to th~~r protei~ precipitant action, astringents are able to reduce the cell permeability. Astringents are also known to inhibit the transcapillary movement of plasma-proteins.. This helps to reduce local edema, exudation and inflamma~on. M~cous secretion is also found to get reduced. When applied topically, astringents in low concentrations are found to stimulate growth of a new tissue. While in high concentration, astringents bring about corrosive effect on contact with tissue. Fig. 9.1. Mechanism of The protein-precipitation brought about by astringent is ascribed to the astringent action presence of metallic ions having large charge/ redius ratio or strong electrostatic fields. The metal would form complex with various polar groups present on the protein or an enzyme. This complexation of important functional groups at the active site of protein or an enzyme causes a drastic change in the properties of the protein. In general, astringents compounds do exhibit (D styptic action, i.e., stopping of bleeding by coagulation of blood and constriction of small capillaries, (i1) antiinflammatory by decreasing supply of blood to the tissues, (iii) antiperspirant by decreasing secretion of perspiration by reducing pore size of skin and (iv) antimicr.obial by protein precipitation mechanism. Astringents have also other uses: (Q They are used to treat diarrhoea. (iQ They also possess deodorant properties. (ii~ They decrease sweating and make the skin toughter. (iv) They promote healing process Some of the compounds for external use having antimicrobial astringent action are described as follows. · · · · KAI (SO4)2' 12H2O ' Mol. wt.: 474.4.. um is potassium aluminium sulphate. It is a double salt having an amount of aluminium equivalent lOftOtlesa than 99.5 per cent of KAI(S04h, 12H20. ~tlon. It is obtained by adding a concentrated sol~tion of potassium sulphate to a hot solution  I p11annaceutJaal Cheml UT (1nor111111lo VoJ,.~ 224. ~ lution is concentrated and cooled.. sulphate When t h e so , of an equimolecular proportion of a1umimum ·. characteristic octahedral crystals separate out. + 24H O ~ 2KAI (SO4)i. 12H20. K2S04 + Al 2 (SO4)3 2.. t hedral crystals are obtained. 1 1 1 e charactensttc regu 1ar oc a If crystallisation is done s 0 ~ Y, arg crystals having a sweet astringent. 1 1 transparent or granu 1ar l.. Properties. It is available as co our ess, t ·t melts in its water of crysta hzatton. At 1 1 ater bath tempera ure 1 · taste. When it is heated s ow Y ~n ': es anhydrous. It is soluble in water but insoluble in 2oooc~·loses its water of crystalhzatton and becom alcohol. d lphate I.. o f a1u minium' potassium ·fication. It gives reactions characteristic an su... It IS Tests for punty.. tested for As, h eavy metals, Fe and Zn. Alum is also reqmred to comply with a test for ammonium salts. Zinc. It is tested by dissolving 1 g alum in 20 ml of water, adding 0.5 ml ~f dilute_ H2~4 a~d 2 g of NH4O and diluting the mixture to 50 ml of water. 1 ml of solution of potassmm femcyarude is added and the solution is kept aside for five minutes. The opalescence produced should n~t be great_er than that produced in a control test obtained by adding 0.5 ml of dilute HCl, 2 g of ammoruum c~onde and.., 1 ml of solution of potassium ferricyanide to 4 ml of 0.11 per cent v /w ZnS04 and making up the ~ volume to 50 ml and keeping it aside for five minutes as we have done in the case of test solution. Ammonium salts. These are tested by doing comparison with a control test. The test alum solution is obtained by dissolving 1 g of alum in 1000 ml of ammonia-free water. To the 10 ml of solution 40 ml of ammonia-free water and 2 ml of alkaline solution of potassium mercuric iodide are added. A colour, if produced, should not be deeper than in a control obtained by adding 2 ml of alkaline solution of potassium mercuric iodide to 1 ml of dilute solution of ammonium chloride in 50 ml of ammonia-free water. ~sa~. It is a~alysed by the gravimetric method. An accurately weighed sample of about 2 g of alum Is dis~~lved m 30? ml of water. To it 20 ml of ammonium chloride solution, 5 drops of methyl red and ~ s~cient quanti~ of a~onia solution are added to produce a distinct yellow colour. The solu~on is heated t_o bod~ng pomt. Then, it is filtered and the precipitate is washed with a 2.5 per cent solution of ammonium nitrate until it becomes free from chloride Th · · · · constant weight at 1200 and weighed. · e prec1p1tate of Al 2O 3 1s dned to a Each gram of residue= 9.307 g of KAl(S04)2. 12HiO a Q Uses. It finds use externally for its astrin ent r.... hence finds use in the preparatio f g. p op~rties. It is having protein precipitation property styptic. ° n toxoids. It is regarded as an antiseptic and used as a local Barbers usually use alum by w tti. d.. e ng it and rubbing 1·t ki ft an antiseptic action. on s n a er shave, perhaps for its astringent Alum is used as a pharmaceutical a i 0 (2) Aluminium Chloride Formula: AIC13,6H2O Aluminium chloride when dried over 8 1 h.. Mol. Jl)t.: 241.43 f lc l 6H O ~ P uric acid for f h. cent o A 3· 2. oµr ours, is having not less, than 95 per  ropJcal Apn,. zzs ~ n. Aluminium chloride ma b f Prepara d'. h Y e prepared by heating metallic aluminium ma current 0 1 chlorine and then isso vmg t e product in water and crystallised. 2Al + 3Cl2 ---+ 2AIC1 3 Aiternativ~ly, aluminium hydroxide is dissolved in hydrochloric acid, upon concentrating the liquid and allowing it to cool, crystals of aluminium chloride separates out. Al (OHh + 3HC1 + 3H2O ---+ AlCl. 6H 3 o 2 Properties..It forms white~d~liquescent, crystalline powder. It is having sweet astringent taste and faint odour. It is very soluble m water and freely soluble in alcohol. In non-polar solvents it exists as a dimer, AlF16. It gets hydrolysed in water and liberates hydrochloric acid. Thus, aqueous solution is acidic to litmus. The hydrochloric acid formed causes irritation to tissue and hence buffering becomes necessary. Uses. The aqueous solution of the compound in 10-25 per cent find use as mild antiseptic and astringent. Due to tissue irritation and staining of clothes, the compound is not used. ~ ~ u m Sulphate Formula: Al 2 (S04h· xH20 Mol. wt.: 342. 14 (anhydrous) , ~ ould have not less than 51.0 per cent and not more then 59.0 per cent of AI (S04h, It contains 2 varying amount of water of crystallization. ~ ~tion. It may _be prepared ~y th~ interaction of fre~hly _precipitated aluminium h~droxide with eqmvalent quantity of sulphuric acid. After the reaction 1s over, the resultant solution gets concentrated and allowed to crystallise. The crystals are filtered and dried. ¼ -mes. Aluminium sulphate forms white crystalline powder or shining plates. It is almost otlourless and is having sweet astringent taste. It is very soluble in water, insoluble in alcohol. The crys~~ salt dehydrates on heating at 250°. Aqueous solution (1 : 20) is acidic and is having pH 2.9. ~ es: It finds use in 5.25 per cent solutions topically. A 10 per cent solution is used for disinfection of a.ental cavities.:J:an antiperspirant, it finds use in 10-15 per cent in creams. It is used as liquid dedorant in solution. · Assay. Its ass ased upon the complexometric back titration method. A known weight is dissolved in 1 N hydrochloric acid, excess disodium edetate gets added, solution neutralised to methyl orange, heated and titrated with standard lead nitrate solution using xylenol orange as an indicator. 4. Aluminium Suhacetate Solution According to USP XVII, 100 ml of aluminium subacetate solution is having not less than 2.3 and not more than 2.6 g of aluminium oxide, and not less than 5.4 and not more than 6.1 g of acetic acid. The. preparation is no longer official.. Preparation. The solution may be prepared by adding dry precipitated calcium carbonate to a solution of aluminium sulphate. Aluminium hydroxide and calcium sulphate both are precipitated. To the mixture acetic acid is added. This reacts with aluminium hydroxide and aluminium subacetate gets form~d. It is filtered, precipitate is washed with more water and volume is made. Boric acid (0.9 per cent) 1s sometimes added as stabilizer. Al2(S04h + 3CaCO3 + 3~0 ----+ 2Al(OH)3 + 3Ca504 + 3CO2i 2Al(OHh + 4C~COOH ----+ 2Al(C~C00h OH + 48iO ~~...