13_Powder_flow_lab

PY511 Cardiovascular and Related Systems: Case 1 - Hypertension

Overview

This experiment focuses on the comprehensive measurement of powder flow properties and the subsequently related critical processes involved in the manufacturing and testing of capsules. The research was spearheaded by Dr. Alison Lansley, with significant contributions acknowledged from Dr. Laila Kudsiova. The study encompasses three primary laboratory components: measuring powder flow, capsule manufacturing and quality control, and calculations related to the filling of capsules. Each part is essential to understanding how formulation variables affect the final pharmaceutical product.

Part I: Measuring Powder Flow

The primary objective of this section is to evaluate the powder flow properties of samples containing various concentrations of a glidant, specifically set at 0%, 0.5%, 1%, and 3%. The experiment utilizes magnesium stearate as the glidant, aiming to determine the optimal concentration that yields the best flow characteristics, which is crucial for ensuring uniformity in capsule filling.

Glidants

  • Definition: A glidant is a substance incorporated into powder formulations to enhance flowability and reduce potential problems such as clumping or inconsistent filling during capsule manufacturing.

  • Functionality: Glidants work by reducing friction and cohesion between particles; they also help shape particles into more spherical forms, improving flow characteristics. However, exceeding the threshold concentration of glidants can adversely affect flow, leading to issues such as poor uniformity in filling or poor handling properties of the powder.

  • Examples: Common glidants include magnesium stearate, colloidal silica, starch, and talc, each with its unique properties and applications in pharmaceutical formulations.

Experimental Setup

The experimental samples included pure lactose and various blends with different glidant concentrations, specifically designed to assess the effect on flowability. The flowability is evaluated using tapped density measurements alongside calculated metrics such as the Hausner ratio and Carr’s index, which provide insights into the powder's flow characteristics and stability.

Measurement Metrics

  • Tapped Density: The volume of powder is measured before and after tapping to assess compaction. The Hausner Ratio (HR) is calculated using the formula:

    HR = Vf / Vt

    • Vf = fluff volume before tapping

    • Vt = tapped volume

  • Carr’s Index (CI): This index serves as another measure of flowability and is calculated by the formula:

    CI = 100 x (Vf - Vt) / Vf

  • Angle of Repose: This measurement is inferred from the measurements of the powder cone height over the base diameter and helps evaluate the powder's stability and flow behavior.

Results

The task results were meticulously documented for various glidant concentrations, with the following metrics noted:

  • 0% Glidant: HR = 1.16, CI = 13.46%

  • 0.5% Glidant: HR = 1.02, CI = 1.49%

  • 1% Glidant: HR = 1.03, CI = 2.92%

  • 3% Glidant: HR = 1.03, CI = 3.03%

Additionally, angle of repose measurements confirmed the variations in flow properties at each defined glidant concentration, with lower angles indicating better flow characteristics.

Part II: Capsules - Manufacture and Quality Control

This section of the lab aims to demonstrate manual capsule filling techniques and assess the uniformity of capsule mass as influenced by the inclusion of glidants in the formulation. Proper capsule formation is critical to achieving consistent drug delivery.

Capsule Formation

Capsules are created from two distinct powder batches: one without glidant and the other containing 1% w/w glidant. Post-manufacture, a uniformity of weight test is conducted on twenty capsules from each batch to evaluate consistency.

Data Collected

Data collection focuses on the filling mass calculations, along with evaluations of the average mass and standard deviation of each capsule type. Average capsule masses were noted as follows:

  • Without Glidant: Average = 427.5 mg

  • With 1% Glidant: Average = 462.3 mg

This data highlights the impact of glidants on mass variation and indicates potential effects on bioavailability and therapeutic outcomes.

Part III: Capsule Calculations

The final component concentrates on calculating the precise amounts of powder required for filling capsules as per a specific prescription involving ferrous fumarate and lactose, key components used in this formulation.

Prescription Details

  • Ferrous Fumarate: Required dosage is 210 mg per capsule, a common element used in pharmaceutical formulations for an iron supplement.

  • Lactose: Used as a filler to occupy the necessary volume within the capsule; its role is key in achieving the desired release profile and stabilizing the active ingredient.

The calculated densities for critical components were determined as follows:

  • Ferrous Fumarate: 1187.6 mg/mL

  • Lactose: 533.7 mg/mL

Calculation Procedure

  1. Volume Determination: Calculate the volume occupied by 210 mg of ferrous fumarate using its density with the following formula:

    Volume of ferrous fumarate = 210 mg / 1187.6 mg/mL = 0.177 mL

  2. Capsule Size Selection: Based on this volume, capsules larger than size 4 must be utilized to adequately accommodate the ferrous fumarate.

  3. Lactose Calculation: The volume of lactose required to fill the capsule is calculated, alongside its mass via density, applying a 50% excess to the final calculations to account for losses during preparation and ensuring accurate dosing.

Conclusion

This comprehensive laboratory experience provided in-depth insights into the significance of glidants within powder formulation and capsule production. It emphasized the integral challenges faced in achieving uniformity in capsule weights and the critical importance of accurate calculations in pharmaceutical preparation, underscoring how formulation variables directly influence the efficacy and quality of the final product.