Formulation factors

Allwood M.C. (1990) Adverse reactions to parenterals. In Topics in Pharmacy Formulation Factors in Adverse Reactions (eds AT. Florence AG. Salole). London Wright. 

G. Levy and R. H. Gumtow, Effect of certain tablet formulation factors on dissolution rate of the active ingradient. III. Tablet lubricants, J. Pharm. Sci., 37. 52,1139-1141 (1963). 

White, Effect of certain tablet formulation factors on 38. dissolution rate of the active ingredients. II. Granule... 

TJ McCarthy. Formulated factors affecting the activity of preservatives. In JJ Kabara, ed. Cosmetic and Drug Preservation. New York Marcel Dekker, 1984, pp 359-388. 

In addition to the effects of formulation factors on freeze-drying behavior, it is important for the pharmaceutical scientist to understand basic principles of heat and mass transfer in freeze-drying [29,30]. Because of the high heat input required for sublimation (670 cal/g), transfer of heat from the heated shelf to the sublimation front is often the rate-limiting step in the coupled heat... 

The system selected here was also a tablet formulation. The five independent variables or formulation factors selected for this study are shown in Table 2. The dependent variables are listed in Table 3. Since each dependent variable is considered separately, any number could have been included. 

A reported application of canonical analysis involved a novel combination of the canonical form of the regression equation with a computer-aided grid search technique to optimize controlled drug release from a pellet system prepared by extrusion and spheronization [28,29]. Formulation factors were used as independent variables, and in vitro dissolution was the main response, or dependent variable. Both a minimum and a maximum drug release rate was predicted and verified by preparation and testing of the predicted formulations. Excellent agreement between the predicted values and the actual values was evident for the four-component pellet system in this study. 

M. Marvola and M. Rajaniemi, Effect of dosage form and formulation factors on adherence of drugs to the esophagus, J. Pharm. Sci., 72, 1034 (1983). 

Insulin aggregation and precipitation was an impediment to the development of implantable devices for insulin delivery as noted by several investigators working with conventional insulin infusion devices [51-54]. The potential causes of the observed aggregation and precipitation are thermal effects, mechanical stress, the nature of the materials in contact with the insulin solution, formulation factors, and the purity of the insulin preparation. 

J.A. Tamada and K. Comyns, Effect of formulation factors on electroosmotic glucose transport through human skin in vivo. J. Pharmaceutical Sci. 94, 1839-1849 (2005). 

Ohtsubo, T., H. Takeda, S. Tsuda, M. Kagoshima, and K. Tsuji. 1989. Formulation factors of fenvalerate microcapsules influencing insecticidal efficacy and fish toxicity. Jour. Pestic. Sci. 14 235-239. 

In the mid-70s, it was a generally expressed opinion that there could be as many as 100 formulation factors that might affect bioavailability or bioequivalence. In fact, most of the documented problems centered around the use of the hydrophobic magnesium stearate as a lubricant or use of a hydrophobic shellac subcoat in the production of sugar-coated... 

C. B. Lalor, G. L. Flynn, and N. Weiner. Formulation factors affecting release of drug from topical formulations. I. Effect of emulsion type upon in vitro delivery of ethyl p-aminobenzoate. J. Pharm. Sci. 83 1525-1528 (1994). 

Physiochemical factors of drug substances Physiological factors of GIT Dosage form and formulation factors... 

Horence AT, Salole EG. Formulation Factors in Adverse Reactions. London Wright, 1990. 

Another important advance adding to the value of PBPK modeling in the pharmaceutical industry are physiological, mechanistic models developed to describe oral absorption in humans and preclinical species. Oral absorption is a complex process determined by the interplay of physiological and biochemical processes, physicochemical properties of the compound and formulation factors. Physiologically based models to predict oral absorption in animals and humans have recently been reviewed [18, 19] and several models are now commercially available. The commercial models have not been published in detail because of proprietary reasons but in essence they are transit models segmenting the gastrointestinal tract... 

Given that extruders of various designs, types and geometries are available in the marketplace, let us examine some aspects that drive selection of the appropriate extruder for a product. The key factors relevant in selecting the extruders are formulation factors (selection of excipients, thermal stability, plasticity, aqueous solubility, and moisture holding capacity) and equipment factors (batch versus continuous operation and scalability of the extruder). 

While in the recent past it was extremely difficult, time consuming and labour intensive to build such a library from purified natural products, with the advent of newer and improved technologies related to separation, isolation and identification of natural products the situation has improved remarkably. Now, it is possible to build a high quality and chemically diverse natural product library that can be suitable for any modern HTS programmes. Natural product libraries can also be of crude extracts, chromatographic fractions or semi-purified compounds. However, the best result can be obtained from a fully identified pure natural product library as it provides scientists with the opportunity to handle the lead rapidly for further developmental work, e.g. total or partial synthesis, dealing with formulation factors, in vivo assays and clinical trials. 

In this study, the influence of several formulation factors on the release kinetics of potassium chloride from directly compressed matrices is investigated. Formulations containing hydrophilic (methylcellulose, carbomer), plastic (polyvinyl chloride) and wax (glycerol palmitostearate) matrix materials at concentrations of 10%, 15% and 20%, and insoluble excipients, were prepared and tested using the USP XXI-NF XVI rotating paddle method. 

The effects of various formulation factors on the in vitro release characteristics of spherical polymethylmethacrylate implants were studied. Physical and mathematical models were proposed to describe the in vitro release profiles. The in vitro release data could be described by a biexponential equation of the following type fraction of tobramycin remaining in the implant at time t=Aerai+BQ, where a, and P represent the rate constants for the initial rapid and subsequent slow phases of release. The influence of drug loading, volume of dissolution medium, implant size and type of cement and the incorporation of water-soluble additives on the release profiles and a and P rate constants is described. 

The influence of the following formulation factors on the release of tobramycin sulphate from PMMA carrier was studied ... 

Table 2 summarizes the effect of various formulation factors on the f fast and slow phase rate constants influence of various formulation factors. For all subsequent discussion, the criterion for statistical significance was/ <0.1. 

Formulation factor Tobramycin0 R2 values for exponential fits ... 

TOBRAMYCIN SULPHATE FROM POLYMETHYLMETHACRYLATE IMPLANTS 177 Table 2—Effect of formulation factors on computer-generated fast (a) and slow ) phase rate constants... 

Kader A, Jalil R. Formulation factors affecting drug release from poly(lactic acid)(PLA) microcapsule tablets. Drug Dev Ind Phann 1999 25(2) 141 151. 

Khalil, S. A., and Ali, M. M. Some formulation factors affecting disintegration and dissolution of chloramphenicol capsules. Acta. Pharm. Suec. 9 563-572, 1972. 

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