Using thermal imaging for control of a manufacturing process

Abstract

A thermal imaging camera monitors the temperature different zones in a pharmaceutical process such as ribbon compaction, coating, spray drying, fluid bed drying, high shear wet granulation, crystallization, lyophilization, precipitation, fermentation, and low dosage dispensing of a pharmaceutically active liquid. The thermal imaging camera can be used to produce a visual display of a temperature profile, or a spray pattern. In addition, feedback from the thermal imaging camera is used to control one or more processing parameters.

What is claimed is: 
     
         1 . A process for coating tablets comprising spraying a coating material in a liquid by at least one spray nozzle onto said tablets while said tablets are in a rotating coating pan, said liquid being a solvent in which the coating material is dissolved, or a carrier in which the coating material is suspended, in which said liquid is caused to evaporate while in contact with said tablets whereby the coating material is deposited onto said tablets, and in which the temperatures of plural regions of said tablets in the rotating coating pan differ from one another through evaporative cooling as said liquid evaporates, the process further comprising scanning said regions using a thermal imaging camera, thereby generating a set of data representing temperatures in said plural regions, and adjusting at least one processing parameter in response to said data, said at least one processing parameter being a parameter from the group consisting of the pressure applied to said liquid upstream of said at least one spray nozzle, the rate of rotation of said coating pan, the temperature of said coating pan, the temperature of coating material being sprayed by said at least one spray nozzle, the temperature of a supply of air directed through said coating pan, and the duration of said process. 
     
     
         2 . The process according to  claim 1 , in which the coating material is sprayed by applying pressure to said liquid upstream of said at least one spray nozzle, said set of data is delivered as an electrical signal to an automatic controller, and said controller controls said pressure. 
     
     
         3 . The process according to  claim 1 , in which said set of data is delivered as an electrical signal to an automatic controller, and said controller controls the rate of rotation of the coating pan. 
     
     
         4 . The process according to  claim 1 , in which said set of data is delivered as an electrical signal to an automatic controller, and said controller controls the temperature of the coating pan. 
     
     
         5 . The process according to  claim 1 , in which said set of data is delivered as an electrical signal to an automatic controller, and said controller controls the temperature of the liquid sprayed though said at least one spray nozzle. 
     
     
         6 . The process according to  claim 1 , in which a supply of air is directed through the coating pan, in which said set of data is delivered as an electrical signal to an automatic controller, and said controller controls the temperature of said air supply. 
     
     
         7 . The process according to  claim 1 , in which said set of data is delivered as an electrical signal to an automatic controller, and said controller controls the duration of said process. 
     
     
         8 . The process according to  claim 1 , in which said coating material in a liquid is sprayed by an array of spray nozzles onto said tablets, and in which said data is utilized to detect failure of one or more of said spray nozzles. 
     
     
         9 . A process of lyophilization comprising subjecting plural vials, each containing a substance to be dried, to a controlled vacuum and temperature in a lyophilization chamber, scanning said vials using a thermal imaging camera, thereby generating a set of data representing temperatures in said vials, and adjusting at least one processing parameter in response to said data, said at least one processing parameter being a parameter from the group consisting of the vacuum level in said lyophilization chamber, the temperature in said lyophilization chamber, and the duration of at least one stage of the lyophilization process.