Liquid dosage forms solutions

Liquid Dosage Forms. Simple aqueous solutions, symps, elixirs, and tinctures are prepared by dissolution of solutes in the appropriate solvent systems. Adjunct formulation ingredients include certified dyes, flavors, sweeteners, and antimicrobial preservatives. These solutions are filtered under pressure, often using selected filtering aid materials. The products are stored in large tanks, ready for filling into containers. QuaUty control analysis is then performed. 

As mentioned earlier in this chapter, penicillins are very unstable in aqueous solution by virtue of hydrolysis of the p-lactam ring. A successful method of stabilizing penicillins in liquid dosage forms is to prepare their insoluble salts and formulate them in suspensions. The reduced solubility of the drug in a suspension decreases the amount of drug available for hydrolysis. An example of improved stability of a... 

Numerous reports concerning the stability of neomycin in various dosage forms have been published. Simone and Popino298 studied the stability of neomycin in liquid dosage forms such as nasal drops, mouth washes and tinctures. The antibiotic was stable in all the formulations tested, except Dobells solution (a mouth wash), for at least 6 months at 20°C. Some formulations were stable for considerably longer. 

The provision of clear liquid dosage forms of substances (such as S5n"ups, solutions)... 

Liquid Dosage Forms Sodium nitropruside in aqueous solution for injection will remain stable for up to one year if protected from light however, its shelf life is about 4h when exposed to normal room light [35]. It has been reported that uric acid increases the photostability of sulfathiazole sodium in solutions [36]. Further dZ-methionine increased the photostability of ascorbic acid in solution [37]. The... 

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). 

Solutions. For oral solutions, elixirs, syrups, tinctures, or other solubilized forms, in vivo BA and/or BE can be waived [21 CFR 320.22(b) (3) (i)]. Generally, in vivo BE studies are waived for solutions on the assumptions that release of the drug substance from the drug product is self-evident and that the solutions do not contain any excipient that significantly affects drug absorption [21 CFR 320.22(b)(3) (iii) ]. However, there are certain excipients, such as sorbitol or mannitol, that can reduce the BA of drugs with low intestinal permeability in amounts sometimes used in oral liquid dosage forms. 

The physical form of a drug product that is pourable displays Newtonian or pseudoplastic flow behavior and conforms to its container at room temperature. In contrast, a semisolid is not pourable and does not flow at low shear stress or conform to its container at room temperature [12], According to its physical characteristics, liquid dosage forms may be dispersed systems or solutions. 

The importance of selecting gravimetry instead of volumetry to measure liquid amounts in the pharmaceutical industry of liquid dosage forms is well illustrated by the volume contraction of water-ethanol and volume expansion of ethyl acetate-carbon disulfide liquid mixtures as well as a CS2-ethyl acetate system. The National Formulary (NF) diluted alcohol is a typical example of the volume nonadditivity of liquid mixtures [29], This solution is prepared by mixing equal volumes of alcohol [U.S. Pharmacopeia (USP)] USP and purified water (USP). The final volume of this solution is about 3% less than the sum of the individual volumes because of the contraction due to the mixing phenomenon [1], In addition, molecular interactions of surfactants in mixed monolayers at the air-aqueous solution interface and in mixed micelles in aqueous media also cause some contraction of volume upon mixing [30],... 

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],... 

Particle Size in Emulsions When a solid drug is suspended in an emulsion, the liquid dosage form is known as a coarse dispersion. In addition, a colloidal dispersion has solid particles as small as 10nm-5pm and is considered a liquid between a true solution and a coarse dispersion [44],... 

Solution A clear, homogeneous liquid dosage form that contains one or more chemical substances dissolved in a solvent or mixture of mutually miscible solvents. 

Syrup An oral solution containing high concentrations of sucrose or other sugars the term has also been used to include any other liquid dosage form prepared in a sweet and viscid vehicle, including oral suspensions. 

During the development of a liquid dosage form of development compound C, it was observed that the solution changed color from slight yellow (initial color due to components in the formulation) to brown. What caused the change in color was the obvious question From one or more of the excipients which have slight yellow color or is it from the degradation product(s) of the... 

Liquid dosage forms. The liquid products are prepared by dissolving the ingredients in the appropriate solvent systems. Dyes, flavors, sweeteners, and antimicrobial preservatives are added to mask unpleasant taste or appearance, and to prevent mold and bacterial growth. The final products are stored in large tanks before final packaging. If the liquid is used for injection or ophthalmic use, the liquid must be sterilized. Solutions for external or oral use do not require sterilization but generally contain antimicrobial preservatives [16, 17]. 

Liquid Dosage Forms. In dry form and at very low moisture content, L-ascorbic acid is very stable, but in solution exposed to air or oxygen it is subject to oxidation accelerated by dissolved trace minerals (copper and iron) and light exposure, l-Ascorbic acid is a reducing agent and is subject to oxidative decomposition in solution. This proceeds first to dehydroascorbic acid, which has full vitamin C activity, but continues to diketogulonic acid and various other breakdown products. The degradation reactions are complex and vary with aerobic or anaerobic... 

The hydrolysis rate of dmgs in liquid dosage forms is strongly influenced by the pH of the solution and can be catalysed not only by H+ and OH ions (specific acid-base catalysis) but also by the components of the buffer used (general acid-base catalysis). We have looked at the ways in which the effect of the buffer components can be removed so that the pH of maximum stability of the solution can be determined from the pH-rate profile and the rate constants for specific acid-base catalysis can be calculated. 

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