INFUSION AND ISOTONIC SOLUTIONS Author: as. Yu.Yu. Plaskonis

Injection dosage forms - a specific group of drugs that require special conditions of preparation, the strictest adherence to aseptic, technological discipline, full responsibility for the preparation, quality control and design to dispensing drugs.

Injection solutions are prepared in aseptic unit

Aseptic conditions - defined conditions, and complex institutional arrangements required to enable to save the drugs from getting into these microorganisms.

Technology process of preparation of solutions for injection consists of the following stages:  Preparation of aseptic unit and the organization of work in aseptic conditions.  Preparation of vessels and auxiliary materials.  Preparation of solvents and drugs.  dissolved drugs.  stabilization or isotones solutions  Quality control solutions.  Filtering solutions to filling bottles, checking the absence of mechanical inclusions.  closing, leak check, preparation for sterilization (marking).  Sterilization.  Quality control and design of drugs to leave.

 Isotonic solutions are solutions, which have an osmolality, equal to the osmolality of liquids of organism (blood, plasma, lymph, tear liquid and ін,).  Name Isotonic originates from the Greek words of isos - even, tonus -pressure.  At introduction of solution with a high osmolality (hypertensive solution) as a result of difference of osmolalities into a cage or red corpuscles and surrounding plasma motion of water begins from red corpuscles to smoothing of osmolalities. Red corpuscles here, delivered part of water, lose the form (shrivel) - there is plasmolysis.  If in an organism solution is entered with osmotic LP (low blood pressure solution), a liquid here will penetrate into a cage or red corpuscles. Red corpuscles begin to distend, and at a wide difference in osmolar pressure inwardly and out of cage a shell does not maintain pressure and torn - there is hemolysis.

Methods of calculating the isotonic concentration  The method, based on equation Mendeleev-Clapeyron or law Van't Hoff  The method, based on a law Raul (for cryoscopy constants )  The method of using isotonic equivalents by sodium chloride.

Expect the amount of glucose for isotones solution  Rp.: Sol. Glucosi of 200 ml isotonicae Sterilisa! D.S. For intravenous introduction  (Equivalent of glucose by sodium chloride - 0,18; depression of temperature of freezing of 1% solution - 0,1; М ,0).

 Isotonic equivalent (E) of sodium chloride shows the amount of sodium chloride, which creates conditions identical osmotic pressure, osmotic pressure equal to 1.0 g of drug.  The isotonic concentration of soluble-sodium of chloride is evened 0,9%.  Solutions of medicinal matters in concentrations, which create osmotic pressure, even such to 0,9% soluble-sodium of chloride, also are isotonic.  Е of glucose/sodium chloride = 0,18, (this amount shows, what amount of sodium of chloride creates in identical terms osmolality, equal to the osmolality 1,0 this substance). 0,18 sodium of chloride - 1,0 glucose 0,9 sodium of chloride - Х Х = (0,9 · 1,0) : 0,18 = 5,0  By the prescription glucose on 200 ml: 5, ml Х ml Х = 10,0 glucose of waterless

Calculation after depression of freezing temperature of solution:  Δt - depression of freezing temperature of solution shows how many degrees Celsius reduces the freezing temperature of 1% solution compared to the freezing point of pure solvent Freezing point depression of serum 0,52. 1% - Δt X - 0,52 o C X= (0,52/ Δt) 1%  Solutions of medicinal substances in a isotonic concentration must have the same depression of freezing temperature. Δt = 0,104 Δt = 0,104 0,52/ 0,104 = 5 % ml Х ml Х = 10,0.

Calculation after equalization of Mendeleyev - Klapeyron: PV=nRT P- plasma osmotic pressure (7.4 atm.) V- volume of solution, l R- gas constant (0.082) T- absolute temperature of the body (310) n- number of mole solute n= P*V/ R*T, n = m/ M, m = M*P*V/ R*T= M* 7,4/ 0,082* 310 m = 0,29* M

By prescription : m = 0,29 · 180,0 = 52,2 glucose of waterless on 1 l of solution, on 100 ml it is needed 5,22, that answers a isotonic concentration. Thus, on 200 ml of solution it is necessary to take a 10,44 glucose of waterless. For preparation of injection solutions and eye drops use glucose taking into account her actual humidity. A calculation is conducted after a formula:  Х = (100 · а) : (100 - в), where and is an amount of glucose after the sample of writing; in is humidity of glucose. If humidity of glucose of 10%, then:  Х = (100 · 10) : ( ) = 11,0