Unit dose powders

Because the regions of the alimentary tract vary widely ia pH and chemical composition, many different commercial formulations of barium sulfate are available. The final preparations of varyiag viscosity, density, and formulation stabiUty levels are controlled by the different size, shape, uniformity and concentration of barium sulfate particles and the presence of additives. The most important additives are suspending and dispersiag agents used to maintain the suspension stabiUty. Commercial preparations of barium sulfate iaclude bulk and unit-dose powders and suspensions and principal manufacturers are E-Z-EM (Westbury, New York), Lafayette-Pharmacol, Inc. (Lafayette, Indiana), and Picker International, Inc. (Cleveland, Ohio). 

Powders for oral use can either be bulk powders or unit dose powders. Bulk powders are usually restricted to less potent medicines intended for symptomatic relief of minor ailments, for example, indigestion. The dose taken is usually measured with a 5-mL spoon, stirred into a quantity of water and then swallowed. This method of measurement can create considerable problems with regard to expected standards of precision dosage. These powders are formulated on the basis of dose weights, whereas the dose is actually measured by volume. A heaped 5-mL spoonful is considered to be equivalent to 5 g of powder. The dose can vary quite considerably, depending on... 

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... 

Capsules are dosage forms in which unit doses of powder, semisolid, or liquid drugs are enclosed within a hard or a soft envelope, or shell. Examples of currently compounded capsules are given in Table 1 with the contents as powders, in oil, or in a semisolid-filled capsule, and modified strength capsules. 

Preparation and administration of orai suspension - Take on an empty stomach 1 hour before a meal. The powder for oral suspension is supplied as unit-dose packets containing an immediate-release formulation of omeprazole. 

Figure I. Reinforcement of silicone gums by carbon blacks (including nonrreinforcmg NR), silica powder (both surface-treated T and untreated NT), and titanium dioxide. The increase in modulus per unit dose and filler concentration depends on filler particle size.

By the use of a breath-powered unit dose dry powder inhaler, which was adapted to the physical properties of TI, relative bioavailability was 50% for the first 3 hours and 30% over the entire 6-hour period in 12 healthy volunteers (Pfutzner et al. 2002). However, although the studies demonstrated pulmonary administration of TI has the advantages of fast onset of action, short duration of action, and lower variability over the SC injections of insulin no attempt has been made to compare pulmonary administration of insulin alone with the same inhaler device. This method of encapsulating biomacromolecules has some advantages and must be considered when electing to deliver a molecule. 

Accuracy of dose/consistency of dosing Tablet and capsule machines are simply quick and accurate volumetric sampling devices that allow us to manufacture unit doses far more quickly than we could by hand. It is easier for a patient to measure a volume of liquid accurately than a weight or volume of powder. 

Dynamic Powder Dis- TM perser Pfeiffer Comp- ressed gas Lactose Cartridge Multiple unit-dose 12... 

Compaction, also known as tableting, involves the compression of the blend into a unit dose. The mechanism for this type of processing has remained unchanged for quite some time. The main components of the compression cycle are pressure rolls, weight adjustment cam, ejection cam, and feed frame. The main considerations when scaling up is compression speed. Compression speed effects dwell time and feed rate. As you go from a small development compression machine to a high-speed production machine, the powder is processed much more rapidly. 

Unit Dosing The division of a powder blend into uniform single portions for delivery to patients. 

Further improvement of this principle of factory-metered blistered unit doses was achieved when GlaxoSmithKline developed the Accuhaler device (also named Diskus in some countries (Fig. 8.7). This multiple-dose DPI device contains a blister strip of 60 unit doses that is transported to the next filled unit dose by pulling a small ergonomic lever prior to inhalation. The powder is presented for aerosolization by peeling back the foil from the blister, which is superior to simple piercing because it is not associated with variability in foil flap shape and device retention. The dose indicator on top of the device tells the patient how many doses are left and decreases each time the lever is pulled. This means that as with most other devices, operation of the dose indicator is associated with the loading operation and not with the inhalation maneuver. 

The active inhaler made by Nektar Therapeutics (formerly Inhale Therapeutic Systems, United States), called Pulmonary Delivery System (PDS), mechanically compresses a fixed volume of air required for delivery and dispersion of a premetered dry-powder unit dose by a spring-loaded pump (Fig. 8.10). Generation of the respirable aerosol cloud thus is independent of the inspiration effort exerted by the patient. The aerosol is generated in a transparent holding chamber that acts as a spacer from which the patient inhales the standing cloud of particles (Patton 1997). The PDS device is actually close to market for inhaled delivery of insulin under the trade name Exubera. 

The MicroDose DPI (MicroDose Technologies, United States) is a breath-activated device that includes a piezoelectric vibrator that converts electrical energy from a battery to mechanical motion that is then transferred into the dry powder. The vibration energy deaggregates and aerosolizes the dose. By controlling the energy input, i.e., the amplitude and frequency of the vibration, the DPI is claimed to be usable for various compounds. As with the devices from Nektar and Dura, the MicroDose DPI uses accurately filled unit-dose blisters. 

Early dry powder inhaler devices were all unit-dose systems and depended on loading and triggering procedures. The Spinhaler and Rotahaler are two early examples of DPI technology. Both utilize premetered doses packed into hard gelatin capsules although different mechanisms of powder delivery are employed ... 

A multiparticulate drug delivery technology for producing CR and taste masked preparations such as liquids, suspensions, effervescent and chewable tablets, reconstitutable powders, and unit dose sachet or sprinkle systems. 

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