(a) What are the reasons for tablet coating?  Given below the major reason for tablet coating ---   1.    To protect the ingredient from environmen t particularly from light, air and moisture. 2.    To mask the disagreeable taste, odor and color of the drug. 3.    To provide physical and chemical protection to the drug. 4.    To control the release profile of the drug form the tablet. 5.    To protect the drug form the gastric environment of the stomach, or to escape the irritating action of the drug to the stomach by using an acid resistant enteric coating. 6.    To incorporate another drug or adjuvant in a coating to avoid chemical incompatibilities or to provide sequential drug release. 7.    To improve the pharmaceutical elegance by the use of special color coating. 8.    To facilitate handling especially during packaging and filling. 9.  ...

Collecting duct Potassium Sparing Diuretics • These drugs give their effect by working is Collecting duct where they inhibits Na+ reabsorption and K+ secretion. These are weak diuretics so mostly used in combination, because filtrate almost 90% reabsorbed before reached to collecting duct.   Machanism Of Action Normally in collecting duct, there are Na+ Channel through which Na+ enter into cells which further transported into blood through Na+/K+ ATPase pump. Now, K+ get back to lumen in exchange of Na+ through k+ channel.   When Potassium sparing diuretics Introduced they give their effects by following two michanism:   i) Aldosterone autogonists.   ii) Sodium channel inhibitors. i) Aldosterone Antagonists Aldosterone is an hormone which bind intracellularly and   increase reabsorption of Na+ and secretion   K+. when these aldosterone antagonist introduces they inhibit the aldoster...

  Distal convoluted tubule (DCT) Thiazide diuretics These are most commonly prescribed drugs. But they also have weak diuretic effect. These drugs give their effect by working in distal convoluted tubule (Dct) where they reduce the absorption of Sodium Chloride by inhibiting Na + Cl -   Cotransporter. Now, In DCT there. Sodium Chloride Cotransporter through which Sodium chloride get in the cell from lumun. Then, sodium get transported to the blood via Sodium Potassium ATPase. While Chloride   Chloride diffuses out on the other side via channel. when thiazide diuretics introduced they inhibit the Na + Cl - cotansporter which decreased Na + Cl - reabsorption and increased urine output. Drug: (a)Benzothiadiazines Hydrochlorothiazide,Benzthiazide,Hydroflumethiazide, Bendroflumethiazide (b) Thiazide like Chlorthalidone, Metolazone,Indapamide, Clopamide Uses - ·        used as diureti...