Objectives:

• Explain why, if the values for bulkiness of lactose and starch are similar,  the density values are quite different. 
• Differentiate between tap density, ultimate tap density, and granule density, and know how to determine each.
• Distinguish between density and specific gravity.
• Determine the capacity of an empty gelatin capsule.
• To observe the differences in true density, apparent density, and bulkiness of some solids commonly used in pharmacy.
• To apply the principles of powder density to capsule preparation

Assigned Readings:

Martin's Physical Pharmacy, 4th edition, Alfred Martin
Pharmaceutical Dosage Forms and Drug Delivery System, 7th edition, Ansel, Popovich, and Allen
Remington's Pharmaceutical Sciences, 17th and 20th editions.

Background:

Particle size and powder density may not, at first, appear to be as important to the practicing pharmacist as it is to the industrial pharmacist. This topic is of importance and utility to the compounding pharmacist. While compounding will be covered in depth in a subsequent course, suffice it to say that the compounding pharmacist is concerned with the size and density of powders intended to be taken internally and applied topically. For example, in the extemporaneous preparation of capsules, it is first necessary to determine the target weight of the contents of the capsules to be prepared. Then it is necessary to select the appropriate size capsule in which to pack the powder. The volume of the excipients becomes important in making these decisions.

Procedure:

During the laboratory period, you will weigh the designated amount of each substance. Then the powder will be placed  in a graduated cylinder and the volume recorded.  On the handout, calculate the true volume, void, porosity, apparent density, and bulkiness of each powder.  True density values will be given for each powder.  The substances used will be lactose, corn starch and sodium chloride.
Five (5) empty gelatin capsules, size 0, will be filled to capacity using the method demonstrated in the lab by the instructor.  Three different substances will be used: kaolin, acetaminophen, and light magnesium oxide.  Weights of the capsule contents will be recorded. 
In addition, students will rotate to the powder laboratory in small groups to observe a demonstration of the pycnometer.