POWDERS

These are mixtures of finely divided drugs. E.g., Pelvis ginger. Powders are encountered in almost every aspect of pharmacy, both in industry and in practice. Drugs and other ingredients, when they occur in the solid state in the course of being processed into a dosage form, usually are in a more or less finely divided condition. Although the use of powders as a dosage form has been declined, the properties and behavior of finely divided solid materials are of considerable importance in pharmacy.Historically powders represent one of the oldest dosage forms.  They are natural outgrowth of the attempt to prepare crude drugs and their natural drugs in more convenient administered form. However, with declining use crude drugs and increasing use of many highly potent compounds, powders as a dosage form have been replaced largely by capsules and tablets.

The advantages of the powder are, they represent a portion of the solid dosage form currently being employed.  The advantages are flexibility in compounding and relatively good chemical stability. The chief disadvantage of powders as a dosage form are, they are time consuming to pre[pare and they are not well suited for the dispensing of many unpleasant testing , hygroscopic or deliquescent drugs. Bulk powders have another serious disadvantage when compared with divided and individually weighed powder; in accuracy of dosage, the dose is influenced by many factors, including settling, fluffiness due to agitation, inaccurate size of the measuring spoon, density of powders, humidity, and personal judgment. Not only do patients measuring varying amounts of powders when using the same spoon , but they often select one differing in size from that specified by the physician.

There are mainly two categories of powders. The first one is the divided powders and the second one is the Bulk powders.

Divided powders:

Divided powders are dispensed in the form of individual doses and generally are dispensed in papers, properly folded. They also may be dispensed in metal foil, small heat-sealed plastic bags, or other containers.

Bulk powders:

Bulk powders may be classified as Oral powders, Dentifrices, Douche powders, Dusting powders, Insufflations, and Triturations.

(a)  Oral powders: Oral powders are generally supplied as a finely divided powders or effervescent granules. The finely divided powders are intended to be suspended or dissolved in water or mixed with soft foods. Antacids and laxatives are frequently administered in this form.

(b)  Dentifrices: Dentifrices are generally prepared in the form of bulk powders, containing soap or detergent, mild abrasive, and anticariogenic agent.

(c)  Douche powders: Douche powders are completely soluble and are intended to be dissolved in water prior to use as an antiseptics or cleansing agents for a body cavity. The most commonly are intended for vaginal use, although they may be formulated for nasal, optic or ophthalmic use

(d)  Dusting powders: Dusting powders are locally applying non toxic preparation that is intended to have no systemic action. They are applied as lubricants, protectives, absorbents, antiseptics, antipruritics, antibromhidrosis, astringents and antiperspirants. They may be micronized or passed through a NO 80 or 100 sieve.

(e)  Insufflations:  Insufflations are finely divided powders introduced into body cavities, such as the ear, nose, throat, tooth sockets, and vagina. Insufflator (powder blowers) is usually employed to administer these products. However, the difficulty in obtaining a uniform dose has restricted their general use. Specialized equipment has been developed for the administration of the micronized powders of relatively potent drugs.

(f)   Triturations:  Triturations are the dilutions of the potent powder drugs, prepare by intimately mixing them with a suitable diluents in a definite proportion by weight.