Question

1. Describe the importance of diluting acids and other liquids especially in the formulation of drugs.
2. Describe the purpose of dilution in adjusting dose and the risks that comes with it.

Answer 1

Formulation of drugs is involve developing a preparation of the drug which is both stable and acceptable to the patient. Solubility, the phenomenon of dissolution of solute in solvent to give a homogenous system, is one of the important parameters to achieve desired concentration of drug in systemic circulation for desired pharmacological response.

Solubility is not to be confused with the ability to dissolve or liquefy a substance, since these processes may occur not only because of dissolution but also because of a chemical reaction. For example, zinc is insoluble in hydrochloric acid, but does dissolve in it by chemically reacting into zinc chloride and hydrogen, where zinc chloride is soluble in hydrochloric acid. Solubility does not also depend on particle size or other kinetic factors; given enough time, even large particles will eventually dissolve.

Oral ingestion is the most convenient and commonly employed route of drug delivery due to its ease of administration, high patient compliance, costeffectiveness, least sterility constraints, and flexibility in the design of dosage form.tbe important factor is bioavailability of drugs.

The oral bioavailability depends on several factors including aqueous solubility, drug permeability, dissolution rate, first-pass metabolism, presystemic metabolism, and susceptibility to efflux mechanisms. The most frequent causes of low oral bioavailability are attributed to poor solubility and low permeability.

Solubility also plays a major role for other dosage forms like parenteral formulations as well . Solubility is one of the important parameters to achieve desired concentration of drug in systemic circulation for achieving required pharmacological response. Poorly water soluble drugs often require high doses in order to reach therapeutic plasma concentrations after oral administration. Low aqueous solubility is the major problem encountered with formulation development of new chemical entities as well as generic development. Any drug to be absorbed must be present in the form of an aqueous solution at the site of absorption. Water is the solvent of choice for liquid pharmaceutical formulations. Most of the drugs are either weakly acidic or weakly basic having poor aqueous solubility.

Dilutions can be important when dealing with an unknown substance.A dilution can be performed not only to lower the concentration of the analyte that is being tested, so that it is in range, but also to help eliminate interferences from other substances that may be present in the sample that can artificially alter the analysis.

Dilution refers to the process of adding additional solvent to a solution to decrease its concentration. This process keeps the amount of solute constant, but increases the total amount of solution, thereby decreasing its final concentration. Dilution can also be achieved by mixing a solution of higher concentration with an identical solution of lesser concentration.

Dilution of drug without reducing the concentration is acceptable in some medical conditions. Some patient doesn't need more fluids intake so in that case for iv administration of drugs we need to reduce the intake of fluids, so the dilution of drug tobe adjust without changing the concentration.

If wrongly dilute the drugs may cause some times increase concentration or decrease in concentration, both are wrong and it affect the effect of drug. Drug will not distribute effectively throughout the body.