Liquid dosage forms types

It is essential to understand how and when the polymorphs of drug substance in oral liquid dosage forms and suspensions can be controlled. One approach to study this phenomenon is to seed the formulation with a small amount of a known polymorphic crystal (other than what is used for the product), which is a common practice to rapidly determine what effect this may have on long-term storage. From these types of studies, the appropriate excipients can be used to preserve the specific polymorphic form desired. However, even when the drug in its crystalline form is studied extensively, there are cases when a previously unknown polymorph may be formed in solution and lead to precipitation (14). 

In solutions, the most important physical factors that influence the solubility of ingredients are type of fluid, mixing equipment, and mixing operations. Generalized Newtonian fluids are ideal fluids for which the ratio of the shear rate to the shear stress is constant at a particular time. Unfortunately, in practice, usually liquid dosage forms and their ingredients are non-Newtonian fluids in which the ratio of the shear rate to the shear stress varies. As a result, non-Newtonian fluids may not have a well-defined viscosity [32],... 

Interactions with Closure Systems. Elastomeric and plastic container and closure systems release leachable compounds into the liquid dosage form, such as nitrosamines, monomers, plasticizers, accelerators, antioxidants, and vulcanizing agents [44], Each type of container and closure with different composition and/or design proposed for marketing the drug or physician s samples has to be tested and stability data should be developed. Containers should be stored upright, on their side, and inverted in order to determine if container-closure interactions affect product stability [6,45]. 

Sulfobutylether P-cyclodextrin can form noncovalent complexes with many types of compounds including small organic molecules, peptides, and proteins. It can also enhance their solubility and stability in water. The first application of sulfobutylether P-cyclodextrin was in injectable preparations it can also be used in oral solid and liquid dosage forms, and ophthalmic, inhalation, and intranasal formulations. Sulfobutylether P-cyclodextrin can function as an osmotic agent and/or a solubilizer for controlled-release delivery, and has antimicrobial preservative properties when present at sufficient concentrations. 

This property can be taken advantage of in almost all liquid dosage forms (Table 90), though in particular applications, some types of povidone are more suitable than others. 

The exact product optimisation studies to be conducted will depend on the type of ophthalmic dosage form to be developed (liquid drops, semi-solid gel/ointment or solid device). However, the dosage form type should be clearly defined from the product design evaluation and supporting preformulation studies, to enable the formulator to focus on the most relevant product optimisation studies. 

The patient s age has a profound influence on the types of dosage forms in which a drug may be given. Pharmaceutical liquids rather than solid dosage forms should be considered for infants and children who are under the age of five years. The liquid dosage forms are generally flavored aqueous solutions, syrups, hydroalcoholic solutions, suspensions, or emulsions, which are administered directly into the oral cavity or administered with food to aid consumption. 

Product quality reviews may be grouped by product type, e.g. solid dosage forms, liquid dosage forms, sterile products, etc. where scientifically justified. This is an appropriate approach for a quality review of non-standardised pharmacy preparations, see also Sect. 34.14.3. 

An interface is defined as a boundary between two phases. The solid/liquid and the liquid/liquid interfaces are of primary interest in suspensions and emulsion, respectively. Other types of interfaces such as liquid/gas (foams) or solid/gas interfaces also play a major role in certain pharmaceutical dosage forms, e.g., aerosols. 

Solid oral dosage forms, particularly tablets, are the preferred type of formulation in the United States. Not only are these products widely accepted by consumers, but they are also relatively cheaper to develop and manufacture than oral liquids or suspensions, par-enterals, or suppositories. Figure 4 shows, quite clearly, that even the elderly primarily make use of solid oral dosage forms [162]. 

Liquids and Suspensions. Most liquid formulations are not packaged in unit-dosage form. Therefore, before administration, the proper amount of medication to be taken for each dose must be measured. This additional requirement may compound any difficulties a patient may have in following a prescribed schedule. Patients suffering from visual impairment, arthritis, or tremors associated with neurological disorders are particularly likely to become frustrated with this type of formulation. Visual impairments make it difficult, if not impossible, for many elderly patients to measure the prescribed amounts of medication accurately. Impaired dexterity, owing to tremors or arthritis, may have effects on a patient s ability to hold both a spoon and a bottle at the same time while pouring out the desired amount of liquid. 

Rate of mucociliary clearance - Concentration of active ingredient - Type of dosage form (liquid, aerosol, powder)... 

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