Optimum formulation

The MUF resin formulation is built up from combination of certain amount of formalin, melamine and urea (in initial and post refluxing stages) and also sorbitol. Variation on the formulation gives different resin properties. The optimum resin properties give the optimum MUF resin formulation. From the properties analysis data, the optimum formulation is determined by using Mixture Experimental Design D-optimal criterion. The selective criteria... 

Example Optimization of the Four Component Flare Mixture. The formulation of the previously discussed flare example was optimized by the Complex algorithm to yield the maximum intensity. The McLean and Anderson mixture equation (9), fit using normal component values and constraints, produced an optimum formulation at X . 5232, X2 . 2299, Xj . 1669, and X . 0800. The Gorman pseudocomponent equation for the same mixture data (7), constrained using... 

Vries et al. [3.59] described the development of a stable parenteral dosage form of the cytotoxic drug E 09. E 09 dissolves poorly in water and its solution is unstable. With the addition of 200 mg of lactose per vial containing 8 mg of E 09, an optimum formulation was developed with respect to solubility, dosage of E 09 and length of the freeze drying cycle. DSC studies have been used to select the most effective parameters. The freeze dried product remains stable for 1 year when stored at 4 °C in a dark environment. 

Three-phase behavior takes place exactly when the surfactant exhibits an equal affinity for both phases, which is indicated by a unit value of Winsor R ratio. This situation has been called optimum formulation because it is associated with an ultra low minimum of the interfacial tension, which en-... 

Figure 7 indicates the phase behavior of SOW systems containing ternary nonionic surfactant mixtures that in turn contain a very hydrophilic surfactant (Tween 60 Sorbitan -i- 20 EO stearate), a very hpophihc surfactant (Span 20 Sorbitan monolaurate), and an intermediate (Tween 85 Sorbitan 20 EO trioleate or Nonylphenol with an average of 5 EO groups). The two intermediate surfactants correspond exactly to an optimum formulation in the physicochemical conditions, i.e., they exhibit three-phase behavior with the system 1 wt. % NaCl brine-heptane-2-butanol. As the intermediate hy-drophihcity surfactant is replaced by an equivalent mixture of the extreme ... 

Taking as a reference the EON = 5 oligomer, which is close to optimum formulation in a system with n-heptane and water at ambient temperature, and has a partition coefficient of 0.02, it means that the EON = 3 oligomer is 6 times less hydrophilic, and the EON = 7 oligomer 8 times more hydrophilic. 

The partitioning can be revealed by different patterns that are found in experimental data. The first one is a reduction in solubilization because a part of the surfactant mixture is no longer at interface. For the same amount of surfactant in the system at optimum formulation, the volume of microemul-son middle phase is lower, just because a certain proportion of the surfactant is no longer in the microemulsion, but has partitioned into one of the excess phases. However, it is worth noting that there are other reasons for the solubilization to decrease, hence this is only a hint. 

Since partitioning is altered by the total concentration of surfactant [44], the optimum formulation for three-phase behavior or for minimum interfacial tension is likely to change with concentration [8,48]. Thus, optimum salinity, optimum ACN, or optimum EON change with the concentration of surfactant if it is a mixture, whereas it is independent of the concentration for an isomerically pure surfactant, as shown in Fig. 10 left and center plots. 

Fig. 10 Effect of surfactant concentration on the optimum formulation (minimum tension position) for anionic mixtures (/e/t), pure anionic surfactant center) and ethoxylated nonionic mixtures (right)...

Fig. 13 Plot of optimum formulation (as optimum salinity) versus nonionic-ionic mixtiue composition. After [33]...

This last case is a combination of the two previous ones, in which the pH has an opposite effect on two surfactants. As shown in Fig. 17 (upper part) and discussed in Sect. 5.2 an increase in pH increases the ionization of the fatty acid, i.e., the proportion of the ionized hydrophilic soap, and hence the hy-drophilicity of the acid-soap mixture in the water phase and consequently at the interface. At low pH, the acid, i.e., a lipophilic nonionic surfactant, prevails, whereas at high pH, it is the hydrophilic soap that dominates the formulation. The pH at which about half of the interfacial mixture is acid and half soap, i.e., the pH at which the interfacial mixture is at optimum formulation (and three-phase behavior is exhibited), is called pH in Fig. 17. 

Salager JL, Vasquez E, Morgan J, Schechter RS, Wade WH (1979) Optimum formulation of surfactant-water-oil systems for minimum interfacial tension and phase behavior. Soc Petrol Eng J 19 107-115... 

Anton RE, Salager JL (1990) Effect of the electrolyte anion on the salinity contribution to optimum formulation of anionic surfactant microemulsions. J Colloid Interface Sci 140 75-81... 

Anton RE, Salager JL, Graciaa A, Lachaise J (1992) Surfactant-oil-water systems near the affinity inversion - Part Vlll Optimum Formulation and phase behavior of mixed anionic-nonionic systems versus temperature. J Dispers Sci Technol 13 565... 

Rivas H, Gutierrez X, Ziritt JL, Anton RE, Salager JL (1997) Microemulsion and optimum formulation occurrence in pH-dependent systems as found in alkaline enhanced oil recovery. In Solans C, Kunieda H (eds) Industrial Applications of Microemulsions, Chap 15. Marcel Dekker, New York, pp 305-329... 

Validation of the mathematical model and then the optimum formulation were then made. 

From a minimum number of experiments, the Hadamard matrix gives the possibility of estimating the mean effects of four parameters. Among them, the particle size range had the most important effect in the release of diclofenac sodium. By interpreting data, a factorial design including only two parameters was applied from which an optimum formulation was found. 

STATISTICAL OPTIMIZATION OF A CONTROLLED RELEASE FORMULATION Table 10—Validity of the optimum formulation... 

An important consideration in the development of soft gelatin capsules is the composition of the LII content, be it solution, suspension, or solid. The contents of soft gelatin capsules vary from solids, solid in liquid, solution or suspension, a combination of miscible liquid, ora simple liquid formulation. It is critical that each formulation is carefully developed depending on the physicochemical characteristics of the drug molecule. An optimum formulation consists of a minimum volume or weight that can be L lied in the smallest possible capsule for ease of administration and for maximum therapeutic effectiveness. Composition of the capsule content and shell composition of commonly available commercial products are presented in Tables 21.1 and 21.2, respectively. 

Salager, J. L., Morgan, J. C., Schecter, R. S. and Wade, W. H. (1979) "Optimum Formulation of Surfactant/Water/Oil Systems for Minimum Interfacial Tension or Phase Behavior". 

Both of these approaches are being explored in an effort to take advantage of the striking improvements in light stability achieved without incurring the real, or at least implied, problems of poor heat stability. Additional stabilizers will continue to be screened and optimum formulations will be selected. 

A direct compression formulation should form a strong compact that can withstand coating, storage, and transportation requirements. An optimum formulation can be... 

Statistical experimental design was used to study the effects of blowing agents, processing aids and fdlers in rigid PVC foam formulations. This technique provided an alternative approach to the classical experimental method of changing one variable at a time. It provided information about interactions between variables and could be used to help to predict an optimum formulation. 24 refs. 

A closer relationship between foam stability and HLB has been reported for two- or three-phase systems surfactant solution-oil or oil-surfactant phase-water [60,109-111]. The effect of various parameters changing HLB on the stability of foams and emulsions has been studied in [111]. These were the concentration of amyl alcohol and sodium chloride, the number of the ethylene oxide groups in the molecule of the oxyethylated octylphenol. As a general parameter of HLB the authors used the surfactant affinity difference concept (SAD) which is an empirical generalised formulation. It measures the deviation from the optimum formulation for three phase behaviour. For anionic surfactants... 

Storage stability has generally been the more serious stability issue faced with therapeutic proteins. Storage stability can be extremely formulation-specific [15,30,32,33], and even with a knowledge of the major degradation pathways in solution, selection of the optimum formulation for a solid is far from obvious. We illustrate the sensitivity of stability to formulation details with studies of an important protein product, human growth hormone. 

The goal of many pharmaceutical formulators is to produce an optimum formulation or process, often for complex problems where two or more objectives are in conflict with each other. In principle, a series of what if experiments could be performed to try to find the optimum, but in practice this process of tiial-and-error is too time consuming and relies too much on luck. Therefore, an optimization technique is required. 

The impact of formulation on virus reduction and product recovery (e.g., potency) was evaluated during terminal freeze dry/dry heat treatment studies with an unlicensed Fraction I derived product, that will be designated Protein G. As shown in Fig. 10, the optimum formulation, that achieved >4 logio PPV inactivation and 80% product recovery, was one that contained 2% albumin, no NaCl, and <0.3%o moisture by the Karl Fischer coulometric method. In contrast, freeze dry/dry heat treatment of product formulated with no albumin, 150mM NaCl and low moisture resulted in approximately 3 logio PPV reduction and 35% product recovery. Thus, minor changes in formulations such as the addition of 2% albumin may impact virus reduction and product recovery during a freeze dry/dry heat treatment. 

Due to the high energy-absorbing abilities of viscoelastic foams, the foams are sometimes called energy-absorbing foams or sound-damping foams. However, die sound-absorption and impact-absorption properties are somewhat different. Therefore, optimum formulations for making them are not exactly the same. 

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