Single-Dose Powders

Single-dose powders are measured quantities of a solid mass packaged in paper or, in the case of industrially manufactured products, in sachets. Single-dose powders are traditionally prepared for children and elderly because of difficulties in 

Powders should be dissolved or suspended in a glass of water or milk or mixed with a small amount of suitable soft food before ingestion, to prevent aspiration into the lungs, as well as to promote direct dissolution of the active substance. Unlike tablets or capsules, powders provide a rapid onset of action because they are readily dispersed. They have a large surface area, and they do not disintegrate but rather just dissolve before absorption. 

Carbasalate calcium is irritating to the gastric mucosa. Therefore, it cannot be administered in capsules. It is administered as single-dose powders in sachets instead. The powders should be dissolved in a glass of water before ingestion. When carbasalate calcium powders are prepared in a pharmacy, the poor flow properties of the active substance may result in a relatively low uniformity of mass. The poor flow of the powder is probably due to an irregular shape of the carbasalate calcium crystals and perhaps also to a relatively wide size distribution of the raw material. 

Divided powders usually contain one or more active substances and excipients. If the quantity of active substance per powder is low, it is supplemented with diluent up to a manageable quantity. A weight range of about 200 mg as a minimum to 500 mg per powder is widely used and assumed to bring along minor loss of active substance during the process (Fig. 4.2) [28]. 

The formulation and preparation of the powder mixture for single-dose powders is to a great extent similar to the one described previously (see Sects. 4.5 and 4.6.2). Excipients that are used for single-dose powders are diluents, and in case of poor flow properties, a glidant. A disintegrating agent is not needed due to the loose packing of particles in the powder. 

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Single dose powders can make changing the drug doses to adjust to the ever changing bodies of children easier. They are also very useful as a specially prepared product for an individual child where only adult formulations are freely available. 

Uniformity of weight (e.g. for tablets, single-dose powders, suppositories, capsules and herbal tea in sachets), disintegration time (for tablets, capsules, suppositories and pills), hardness and friability (for example, uncoated tablets), viscosity (for internal and external fluids), consis-... 

Fig. 4.2 Nifedipine contents in single-dose powders or capsules that were meant to contain nifedipine 1 mg as active substance (from crushed tablets Adalat 10 mg retard) and microcrystalline cellulose (MCC) as a diluent. The batch size was 50 single-dose powder or capsules and no excess tablets were used. Capsules number 4 (80 mg MCC), 3 (130 mg MCC) and 1 (200 mg MCC) are compared to oral...

After all solids are mixed, the powder mixture is divided over the dose units. For single-dose powders this is done by weighing the powders individually on waxed powder papers. Each paper is folded. Powder filling and folding machines are no longer used in most countries. Packets (papers) should be checked to see that they are uniform in weight. 

The in-process controls for the preparation of the powder mixture are the same for single-dose powders as for capsules. 

For single-dose powders, the average weight and the uniformity of mass are determined. The specifications for content uniformity are discussed in Sect. 32.7.2. 

The preparation of the powder mixture is analogous to the preparation of single-dose powders (see Sect. 4.5), but the flow properties are less critical, because the powder mixture does not have to be distributed evenly over dose units. A diluent is generally not necessary, but in case it is required, lactose is often used. Bulk or multidose powders can be packaged in glass, plastic, metal or other containers that have a wide mouth to allow the handling of the powdermeasuring device. 

Single-dose powders are packaged in a suitable powder fold box, a plastic bag with locking clip or, in case of an authorised medicine, in sachets. 

Single dose oral powders are dispensed in powder paper or sachets. For the packaging of single dose powders, paper qualities of 40-120 g/m should be used. Powder paper must not be contaminated, should not shed fibers and there should be minimal variance in weight per area (= constant powder paper weight) within each batch. 

Mixing of solids takes place in the pharmacy in the preparation of capsules, single-dose powders and multidose powders. But also in the preparation of suppositories and dermal preparations solids may first be mixed together before they are combined with the base. A common reason for this is that mixing solids may give an opportunity to ... 

In the Netherlands it is commOTi to use a requirement of 3 % as a limit to the deviation of the average mass towards the calculated mass for capsules and suppositories. Eor single dose powders this requirement is 5 %. In practice these limits appear to be acceptable and are achievable. When these limits are exceeded, then there are, in principle, two possibilities reject the preparatirai or check the average content. When the content comphes, the preparatirai need not be rejected on the basis of the average mass discrepancy. However the cause of the deviation should be investigated and traced and corrective measures should be taken for future batches. 

In ampules or vials that contain powder or crystals, to which a liquid (called a diluent) must be added before the drug can be removed from die vial and administered. Vials may be single dose or multidose vials. 

Pharmaceutical powder is a mixture of finely divided drugs and/or chemicals in dry form. They are dispensed as bulk powders or divided powders. When the prescription is received for powders, first determine whether it is based upon one unit or upon a bulk formula to be subdivided into individual units. Bulk powders are provided as multiple doses in a container and the patient measures the dose as instructed at the time of administration. Some examples of bulk powders include Tolnaftate Powder USP and Nystatin Topical Powder USP as antifungals, and Desitin Powder for diaper rash. Divided powders are meant to be provided as single dose units in individually wrapped powder papers. Such single dose packets are stacked in a powder box, and the label... 

Powder container. Dry powder inhalers may contain the dry powder formulation in many different forms. The first DPI, the Spinhaler contained single doses in capsules. Other systems, like the Diskus or Diskhaler may contain the metered dose in blisters, whereas systems like the Turbohaler , or Novolizer , have multi-dose containers. 

These can be attributed to inhibition of cyclooxygenase (p. 196). ASA can be given in tablet form, as effervescent powder, or injected systemically as lysinate (analgesic or antipyretic single dose,... 

Sodium-restricted diets Each buffered tablet contains 264.5 mg sodium. Each single-dose packet of buffered powder for oral solution contains 1380 mg sodium. Hyperuricemia Didanosine has been associated with asymptomatic hyperuricemia consider suspending treatment if clinical measures aimed at reducing uric acid levels fail. 

Dosage form ReFacto is a sterile lyophifized powder for injection available in nominal dosage strengths of 250, 500, and 1000 international units (lU) per vial. Recombinate is formulated as a sterile lyophifized powder preparation of concentrated recombinant AHF for intravenous injection and is available in single-dose bottles which contain nominally 250, 500, and 1000 lU per bottle. The final product contains an insufficient quantity of von Willebrand Factor to have any clinically effect in patients with von Willebrand s disease. 

Parenteral 82, 600, 1200 IU powder in single-dose vials or 415, 568, 1026 IU in prefilled pens with needles for subcutaneous injection... 

Parenteral 5 mg/mL in multiple-dose vials, or 7.5 mg powder in a single-use kit, or 30 mg (4-month depot), 45 mg ( -month depot) in a single-dose kit for subcutaneous injection... 

VIDEX buffered powder for oral solution is supplied for oral administration in single-dose packets containing 100, 167, or 250 mg of didanosine. Packets of each product... 

Figure 8.5 Capsule-based single-dose dry-powder inhalers Spinhaler and Rotahaler. [From Ganderton and Kassem (1992). Reproduced with permission from Elsevier ]...

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