Dietary management of surgical patients: effects on incisional wound healing

A study of 38 patients was undertaken at the main University Hospital in Alexandria. The sample was divided into a control group and an experimental group. Findings show statistically significant differences between the two groups in the level of education, but no difference in blood picture, body mass index or nutritional status. There was a difference in the rate of wound healing in the two groups, and a relationship between the nutritional status and wound healing in the control group. Total hospital stays for the control group were longer than those for the experimental group. The nutritional status of surgical patients, as well as their food intake, should be evaluated at short intervals before and after surgery

Factorial design of experiment for stability studies in the development of a tablet formulation.

The stability of chlorpromazine hydrochloride in some hypothetical tablet formulations was evaluated through a fractional factorial design of the type N = 2(6-3). The factors studied were the type of filler (X1), lubricant (X2), binder (X3), disintegrant (X4), the absence or presence of light ( X5 ) and/or humidity ( X6 ). Statistical analysis of the stability data allowed the derivation of a regression equation which determined the magnitude and direction of change of each factor level to optimize drug stability. The significance of the factors could be arranged in the following order: X5 greater than X2 greater than X3 greater than X6 greater than X1. The effects of X4 and the two-factor interaction X2X3 were found to be insignificant. The best multi-component excipient mixture was evaluated on the basis of the information deduced from the factorial design.

Use of a fractional factorial design to evaluate granulations prepared in a fluidized bed.

Sulfadiazine granules were prepared in a fluidized bed granulator. The granulation conditions such as binder concentration, velocity and temperature of fluidizing air, pressure of compressed air and binder solution flow rate were studied at two levels, low and high. By applying fractional factorial design the effect of these granulation conditions as well as the interaction among them, on the granules physical characters were assessed.

The construction and uses of factorial designs in the preparation of solid dosage forms.

The present experiments were factorially designed to study the effect of particle size (X3), at different levels of both temperature (X1) and time (X2), on the hardness and mechanical strength of sintered tablets. A 2 X 2 X 3 design was constructed for salicylamide tablets with X1, X2 and X3 at 2,2 and 3 levels respectively. For phenobarbital tablets, a 3 X 3 X 3 factorial experiment was run. On the basis of analysis of variance, empirical regression equations have been developed. Within the limits of the factors, it was found that the quadratic effect of X 2/3, on the average, was the most significant. The significance of the linear effects was in the following order: X3 greater than X1 greater than X2 in salicylamide tablets and X1 greater than X3 greater than X2 in phenobarbital tablets. A change of X3 from the high to the low or intermediate levels caused an increase in the mechanical properties of tablets. The only linear interaction was that of X1X3 for the hardness data of phenobarbital tablets, but it was of least significance among the other effects. Other quadratic main effects of X 2/1, X 2/2 and quadratic interaction effects of X 2/3X1 and X 2/1X2 were also found to be significant. The optimum values of the factors studied, that would maximize any given mechanical property, were located.

The construction and uses of factorial designs in the preparation of solid dosage forms. Part 3. Effect of temperature and time on the mechanical properties of sintered tablets.

The present and forecoming series of experiments illustrate the application of factorial design to the study of the sintering phenomena of pharmaceutical tablets. This part was concerned with the effect of temperature (X1) and time (X2) on the mechanical properties of sintered tablets. A 2 X 2 design was developed for salicylamide tablets with the two factors at two levels, and a 3 X 3 design for phenobarbital tablets with the two factors at three levels. Analysis of variance was used to determine the significant effects. Empirical regression equations were obtained which indicated that the hardness of sintered tablets was markedly improved by using the high level of X1 at the low level of X2 in phenobarbital tablets, and the high levels of both X1 and X2 in salicylamide tablets. The tablets tensile strength was a linear function of X1 and X2, but the interaction effect X1X2 was insignificant. Significant quadratic effects of X2/2 and/or X2/1 were also detected for the mechanical properties of phenobarbital tablets.

The construction and uses of factorial designs in the preparation of solid dosage forms. Part 1: Effervescent acetylsalicylic acid tablets.

The construction and application of a fractional factorial design of the type N = 2(5-2) for the preparation of effervescent acetylsalicylic acid tablets by a new technique was demonstrated. This method involved direct compression of the tablet ingredients, dipping the tablets in a volatile mixed solvent system and subsequent removal of the solvent. With the help of a derived regression equation, the factors considered most likely to have a beneficial effect on tablet hardness were: the compression force, the percent of acetylsalicylic acid content/tablet, the particle size of tablet ingredients and the solvent ratio. The time of dipping was found to have an insignificant effect on tablet hardness. By following the path of the steepest ascent, effervescent acetylsalicylic acid tablets of remarkable hardness, friability and dissolution time were obtained. The optimum conditions for preparing these tablets were determined.

The construction and uses of factorial designs in the preparation of solid dosage forms. Part 2: Granulation in a fluidized bed.

With the help of a factorial design of experiments, the optimum conditions for preparing aminophenazone granules in a fluidized bed were established by which high quality tablets were obtained with a minimum energy expenditure. Granules with given technological properties could be prepared by controlling the regime of the granulation process. By varying the experimental conditions, a reproducible correlation was found between the parameters of optimization (mean granule diameter and work of compression) and the factors controlling the granulation process (pressure of compressed air, velocity and temperature of fluidizing air and binder concentration). The effect of the granule quality on tablet physical properties was discussed. Recommendations were given for the exploitation of fluidized bed units in the practice of granulation and tableting.

Aspirin stability in solid dispersion binary systems.

The stability of aspirin in its solid dispersion with urea or povidone was investigated at two accelerated storage conditions. The observed aspirin degradation in both systems followed the first-order rate equation. The water sorption ability of the two carriers as well as the alkalinity imparted by urea could possibly be the most important factors responsible for the observed acceleration of aspirin decomposition. The results also showed that the temperature effect was more pronounced than the humidity effect. Generally, coprecipitated samples exhibited slightly higher degradation rates than physically mixed ones.

Solid dispersion of pharmaceutical ternary systems I: Phase diagram of aspirin-acetaminophen-urea system.

The phase diagram of an aspirin-acetaminophen-urea system was constructed. The data obtained by the thermomicroscopic method showed that the binary systems of aspirin-acetaminophen, aspirin-urea, and acetaminophen-urea are simple eutectic mixtures with negligible formation of solid solutions or molecular compounds. The equilateral triangular phase diagram of the ternary system revealed that it forms, upon solidification, solid dispersions of the mechanical mixture type. The ternary eutectic corresponded to a composition of 60% aspirin, 20% acetaminophen, and 20% urea at 72 degrees. The method of calculating the composition finally solidified melts, lying within any area of the phase diagram, is presented. Use of the phase diagram in selecting the optimum ratio of components to enhance dissolution rates of these drugs may be possible.

The application of solid dispersion technique in the preparation of therapeutic tablets. Part 1: Paracetamol, amylobarbitone, and caffeine tablets.

A trial was made to study the possibility of preparing high-quality therapeutic tablets by direct compression of the solidified drugcarrier melt via solid dispersion technique. Paracetamol-mannitol, amylobarbitone-urea and caffeine-nicotinamide systems were investigated. Phase diagrams of the first two systems were found to be of the simple eutectic type, while that of the third system was a peritectic type. Solubility studies were also carried out. Dissolution rate studies showed that the fused mannitol/paracetamol (80:20), urea/amylobarbitone (80:20) and nicotinamide/caffeine (50:50 and 70:30) solid dispersions exhibited better rates of dissolution than those of the pure drugs. Comparative studies were carried on with tablets prepared by direct compression of the drug-carrier solidified melt exhibiting the highest dissolution rate and by slugging the pure drug and the drug-carrier physical mixture of corresponding composition. The physical properties and dissolution rate data showed the superiority of the tablets prepared by the solid dispersion technique. The drug release from these tablets was 4.5, 7.6 and 3.7 times greater than that from tablets prepared from pure paracetamol, amylobarbitone and caffeine respectively.

The effect of crystal forms of some barbiturates on their pharmaceutical properties. Part 1: Phenobarbitone.

Up to 13 polymorphic forms of phenobarbitone have been reported in the literature. By melting the commercial sample and cooling under specified controlled conditions, three polymorphic forms II, II, XII, and a mixed form of II and III were obtained. The interconversion of the different forms was studied by special procedures including suspension in water, heating, and heavy dry grinding. The hydrated form XIII and a new hydrated one, designated XIV, were produced by suspending different other forms in water. Heating was found to affect transformation from any form to form I. IR spectroscopy and hot stage microscopy were used for the identification of the different polymorphic forms. Initial dissolution rate studies were carried out on only five forms. The dissolution rate constants were in the following decreasing order: II greater than III greater than I greater than XIV greater than XIII. Form II was found to dissolve at a rate constant about twice that of both hydrated forms.

Dissolution studies on paracetamol solidified melt prepared under different cooling rates.

Regulating the cooling rate of paracetamol melt resulted in the formation of different microcrystalline structures of the solidified melt. Dissolution rate studies were carried out on powdered samples prepared from fused paracetamol that was crystallized under different conditions. Rapid cooling associated with stirring the melt during crystallisation produced a fast rate of dissolution in the order of two times greater than the untreated drug. Increased dissolution rate data were masked to some extent when working with tablets prepared from the corresponsing solidified and powdered melts. The present study represent a new method of physical modification of drugs as a means of increasing rate of drug dissolution and absorption.

Physicochemical study of drug binary systems. Part 3: Tolbutamide-urea and tolbutamide-mannitol systems.

The phase diagram of the tolbutamide-urea system, constructed by data obtained from the microheating table apparatus, was a peritectic type. It showed the possibility of the formation of two molecular compounds with incongruent m. p. at 112 degrees C and 123 degrees C. Metastable and stable eutectic points were observed at 63 degrees C and 92 degrees C respectively. The phase diagram of tolbutamide-mannitol system revealed that in addition to eutectic liquefaction at 102 degrees C and 6% (w/w) mannitol, there was a region [40--80% (w/w) mannitol] in which the two components were not completely miscible in the liquid state. Solubility studies showed an increase of about 2.5 fold in the solubility of tolbutamide with 0.5 g% urea and suggested the possibility of the formation of a low-solubility complex in addition to a soluble higher complex of the two components. No obvious increase in the solubility of tolbutamide was detected in the presence of mannitol. A full description of the nature and composition of the final solidified melts of the two present systems could prove to be helpful in the explanation of the dissolution behaviour of the different studied samples and their corresponding physical mixtures. The fused 90% urea and mannitol solid dispersions showed a fast rate of dissolution in the order of 15 and 10 times (respectively) greater than pure tolbutamide.