INHALATION PREPARATIONS ( AEROSOLS ) Defination : Inahalation Preparation are liquid or solid dosage forms intended for administration as vapours or aerosols to the lung in order to obtain a local or systemic effect. They contain solution or dispersion of one or more active ingredients which may be dissolved or dispersed in a suitable vehicleThere are two types of Pressurized Metered Dose Inhalers : 1. Two phase system consisting of gas and liquid 2. Three phase system consisting of gas, liquid and solid or liquids. STANDARD TESTS OR EVALUATION : Pressurised Metered – Dose Preparation – 1) Description : It should comply with Specification of Products. 2) Content of active ingredient delivered per actuation : Shall Comply with the specification. 3) Uniformity of delivered dose : The preparation complies with the test if 9 out of 10 results lie between 75 to 125 % of the average value and all lie between 65 to 135 % . If 2 or 3 values lies out side the limits of 75 – 125 %. Repeat the tests for two more inhalers. Not more than 3 of 30 values lie out side the limits of 65 – 135 %. 4) Particle size : The number of pariticles longer than 20 micron meter dosent exceed 50 and no particles exceeds 100 micron meter in length. 5) Number of deliveries per containers : The number of deliveries so discharged in the test for particles size is not less than the number stated on label. 6) Deposition of emitted dose : as per IP or the specification. 7) Leak Test : A average leakage rate of the 12 containers should not more than 3.5 % of the net fill weigh per container and none of the containers leaks more than 5 % of the net fill weight per yearPOWDER FOR INHALATION : Powder for Inhalation are presented as single dose powders or multi dose powders. For pre- metered inhaler, the inhaler is loaded with powders pre- dispensed in capsules or other suitable pharmaceutical dosage form. 1) Description : It should comply with Specification of products. 2) Uniformity of delivered dose : The Preparation complies with the test if 9 out of 10 results lies between 75 – 125 % of the average value and all lie between 65 - 135 % . If 2 or 3 value lies out side the limits of 75 -125 % . repeat the test for two more inhalers. Not more than 3 of the 30 values lies out side the limits of 65 – 135 %, 3) Uniformity of content : As given in capsules. 4) Number of deliveries per container : The number of deliveries so discharged in the test for particles size is not less than the number started on label