Water for pharmaceutical use shall be free from any cations, anions, heavy metals & any other impurities why?

   Water for pharmaceutical must be free from inorganic as well as organic impurities, minerals, and heavy metals. Some impurities like calcium, magnesium, ferrous are responsible for degradation of drug molecule, many cations like ferrous and calcium magnesium act as catalysts in degradation reaction of drug molecule, anions like chloride are highly active they participate in nucliophylic substitution reactions, where in they break a double bond between -C=C- in to a single bond as CL –CH-CH2- , which a reason why we observe that color dies tend to fed in presence of chlorine as most of the dies used are diazo compounds which has plenty of places for nucliophylic substitution reactions, which is also a reason why stability of drug is drastically affected in presence of cations and anions from mineral origin present in water.

    Heavy metals like lead and arsenic are highly cumulative neurotoxic metals, heavy metals are not eliminated out of our body easily like other drugs and molecules but heavy metals bind with proteins and tend to get accumulated in fatty tissues, nerve tissue is most likely to get damaged by heavy metals, heavy metal causes nervous tissue damage there for water must be free from heavy metals.

Why water for pharmaceutical use is always kept in close loop in continuous circulation?

Water is very important & essential medium for any pharmaceutical preparation. So this use very carefully.

      Water is a best medium for most microorganisms, microorganism can be a highly pathogenic which causes serious diseases(many diseases are  water born), these pathogens infect after consumption of contaminated water, microorganisms tend to settle on a surface if water is allowed to stand in a stagnant position for few hours, these settled microorganism form a film over the surface of vessel and piping, such film formed by microorganisms is also called as bio-film, bio-films are very difficult of remove, once a bio-film is formed at a particular point then that point may form a bio-film again even after cleaning very easily as seed from this point is may not completely get removed effectively.

   Bio-films then can become a source of microbial contamination's, therefore purified water after collection in a distribution system is always kept in a closed loop in a continuous circulation.

      A continuous circulation is also not enough at some points, therefore it is aided with high temperature range from 65 °C to 80°C, a minimum temperature of 65 °C is considered a self sanitizing, but better assurance is obtained with a temperature of 80°C.

      Purified water collected should be stored in a stainless still vessel which must facilitate distribution to the point of use in a closed loop of continuous circulation, tank should be made of corrosion free material of construction, and must facilitate sanitization and easy cleaning. Thank's

Why some medicine come in capsule form?

  Some medications come in capsule form, because the nature of the substance makes it difficult or impossible to manufacture in a tablet form. Creating a tablet requires finding a binding material that allows the medication to be formed into a solid shape but that does not affect its chemical composition nor its bio-availability. For example, the typical aspirin tablet is held together mostly by corn starch.

  Some medications come in capsule form, because many consumers have a distinct preference for capsules. Many consumers perceive capsules as easier to swallow. Some consumers perceive capsules as more effective.

   An interesting example of the preference for capsules is provided by a study ("Effect of Shape of Medication in Treatment of Anxiety States") published in 1972 in the British Journal of Psychiatry by psychiatrist M. Z. Hussain, who found that patients being treated for anxiety responded better to treatment with the same drug (chlordiazepoxide) in capsule form rather than tablet form. There is no known medical reason for this, but its psychological significance is compelling. Capsules have been the required form for most clinical trials of psychiatric medications since 1972.

  Also some reason in capsule form because:-

       1. The nature of chemical substance. 

       2. Rapid bio availability rather than tablet.

       3. Easy to swallow for older and child patient. 

       4. Easy to manufacture where tablet need to more step.

Difference between relative humidity and humidity.

This is very important thing for the pharmaceuticals also any other organization, so need to know difference between this..

       "Humidity" and "Relative Humidity" are not the same thing. Humidity means amount of water vapor present in air with respect to total amount of air.         Relative Humidity is the amount of moisture in the air 'relative' to the temperature (i.e. relative humidity is the amount of moisture in the air compared to what the air can "hold" at that temperature. When the air can't "hold" all the moisture, then it condenses as dew).

          The relative humidity is a measure of the amount of water vapor in the air (at a specific temperature) compared to the maximum amount of water vapor air could hold at that temperature, and is given as a percentage value. Relative humidity depends on the temperature of the air.