The pan coating process, widely used in the pharmaceutical industry, is among the oldest industrial procedures for forming small, coated particles. Unlike many other microencapsulation processes, the process tends itself to great flexibility in formulation of coating. Core material may contain wide range of additive may serve to modify release properties of formulation.

Pan coating method of microencapsulation process contains two steps:
  1. Preparation of core material
  2. Coating procedure
Preparation of core material
  • For the satisfactory pan coating core particles should be of greater than 500 micron, spherical shape, adequate hardness and low friability.
  • Very few drugs satisfy these requirement hence the following approaches are used for preparation of core:
    1. Use of spherical substrate such as nonpareil sugar seeds
    2. Coating of fine powdered medicament to the large crystal of same medicament
    3. Incorporation drug into suitable matrix
Coating procedure
Steps involved in coating of batch of cores :
  1. Roughening of inner surface of pan if it not contain baffle
  2. Screening of core material to remove dust
  3. Core material addition
    • Pour method
    • Spray method
  4. Addition of dusting powder such as talc at the critical moment just as core become tacky and just in sufficient amount to free up any clumps
  5. Drying and jogging after each application of coating
  6. Application of coating & drying in flat trays at 40 0C                                                                                                                             
Equipment and related facilities

Pan coating apparatus
  • The particles are tumbled in a pan or other device while the coaing material is applied slowly
  • The pipe of the blower stretches into pot for an evenly heating distribution while the coating pan is rotating