Pharmaceutical Powders Overview

Study Notes

Introduction

Powders are a solid dosage form composed of finely divided particles.
Powders can be used internally (oral powder) or externally (topical powder).

Historical Use

Historically, powders have been used as internal and external medications.
Internal uses include oral administration, nasal administration (snuffs), and insufflation into body cavities.
External uses include application to compromised skin areas.
Powders are used to make solutions for topical, oral, and douche applications.
Recent advancements include bioadhesive powders that adhere to specific areas for prolonged drug effects.

Applications

Powders allow for easy dose adjustments by a primary care provider compared to capsules or tablets.
Powders facilitate clinical studies due to the flexibility in dose adjustments.
While medicated powders are limited in therapeutics, powdered substances are widely used in preparing other dosage forms.

Powders: Composition

Well-prepared powders have uniform, small particle sizes for an elegant appearance.
Powders are typically more stable than liquid dosage forms and dissolve rapidly, allowing for quick drug absorption.
Particle size affects powder properties. Larger, denser particles settle faster than smaller particles; bulky particles settle slower.
Powder stability is influenced by large surface area exposed to atmospheric conditions. Powders should be stored in tight containers.
Smaller particle sizes present a greater surface area and can adsorb gases, affecting wetting properties.
Increased surface free energy can enhance drug solubility and bioequivalence.

Topical Powders

Topical powders should have a uniform, small particle size to avoid skin irritation.
Ideal topical powders are impalpable, free-flowing, adherent, and passed through a No. 100-mesh sieve to minimize irritation.
Highly sorptive powders are not suitable for oozing wounds, as they can form crusts.
Water-repellent powders prevent water loss from the skin and avoid caking on oozing surfaces.
Talc and other natural products used on open wounds should be sterilized to prevent infection.
Topical powders typically contain a base (cornstarch or talc), an adherent (magnesium, calcium, or zinc stearate), an active ingredient, and an aromatic material.
Powders should flow easily, spread uniformly, and provide a large surface area for absorbing perspiration and cooling sensation.

Insufflated Powders

Insufflated powders are finely divided powders intended to be administered into body cavities using a device.
Common uses include nasal and vaginal application.
Powders for insufflation require careful formulation to avoid irritation and ensure proper delivery.
Particle size is crucial for proper insufflation and drug delivery to the target site.
Insufflated powders should be free-flowing and adhere to the target site.
Common examples include nasal corticosteroids, antifungal medications, and antihistamines.

Granules

Granules are prepared agglomerates of powdered materials.
They can be used directly for their medicinal value or as a pharmaceutical ingredient.
Granulation improves powder flowability, compressibility, and dissolution properties.
Granules are often used in tablet formulation.

Advantages of Powders

Easy dose adjustments.
Simple formulation process.
Relatively stable.
Rapid dissolution and absorption.

Disadvantages of Powders

Potential for particle size variation.
Sensitivity to moisture and humidity.
Difficulty in handling and dispensing.
Potential for dust generation.
Potential for drug degradation due to large surface area.

Description

Explore the fascinating world of pharmaceutical powders, their historical applications, and modern advancements. This quiz covers the composition, uses, and benefits of powders in drug administration, both internally and externally. Test your knowledge on the flexibility and clinical impact of powdered dosage forms.