PubMed · 4862948
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I C Edmundson. 1967. Particle-size analysis.. https://pubmed.ncbi.nlm.nih.gov/4862948/
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Packages that provided stability (less than a 10% loss in potency) of a moisture sensitive compound (PGE-7762928) in tablet form at accelerated conditions for 6 months were identified. The equilibrium moisture content of the tablets at 25 degrees C/60%RH, 30 degrees C/60%RH and 40 degrees C/75%RH were 2.3,2.4, and 2.9%, respectively. The tablet equilibrium moisture content, degradation rate of unpackaged product, and the moisture barrier properties of the packages were used to predict the stability of the packaged product. The physical and chemical stability (HPLC assay) of the products were measured after 2,4,6,8,12, and 24 weeks at ICH conditions. The Containers-Permeation(1) of polyvinyl chloride blisters, cyclic olefin blisters, aclar blisters, cold-form aluminum blisters was 0.259, 0.040, 0.008 and 0.001 mg per blister per day, respectively. At 6 months at 40 degrees C/75%RH, the percent active was 84% in polyvinyl chloride blisters, 91% in cyclic olefin blisters, 97% in aclar blisters, 100% in cold-form aluminum blisters and 99% in an high density polyethylene bottle with a foil induction seal. The stability results for the packaged product were fairly consistent with the predictions based on the moisture sensitivity of the product and the moisture barrier properties of the respective package. To gain a better prediction, the flux value determined by the Containers-Permeation procedure was adjusted for the internal moisture concentration of the blister.
Changes in the rheological properties of four o/w cream formulations differing in the combination of surfactants were studied. The non-ionic surfactants used were soybean derivatives, polyethylene glycol 10 and 25 soya sterol, and sorbitol derivatives, sorbitan monooleate and trioleate. Combinations of the soybean and sorbitol derivatives were used. The rheological properties were tested during a 28-day storage period at three different storage conditions (cold, room temperature and accelerated conditions). In addition to dynamic and static rheological tests, droplet size distributions and conductivities of the creams were also determined. The consistency of the creams containing polyethylene glycol 10 soya sterol decreased during storage. Despite the greatest decreases in consistency, the creams containing polyethylene glycol 10 soya sterol exhibited the most viscoelastic structures with linear viscoelastic behaviour. Storing the creams for 28 days in the three different storage conditions made the differences in the consistency of the formulations smaller. All three storage conditions were involved when the conditions of the most viscoelastic cream of each formulation was specified. In the case of linearly viscoelastically behaving creams containing polyethylene glycol 10 soya sterol, all the rheological tests correlated with the droplet size distributions and the conductivity tests.
The solubility of seven drugs (nitrofurantoin, chlorothiazide, phenobarbital, prednisolone, griseofulvin, diazepam and piroxicam) in the absence and presence of gelatin was measured, at three different pH values (3.7, 5.0 and 7.0) at 37 degrees C. Drugs studied had different physicochemical properties (log P, pK(a), aqueous solubility) and their solubility in presence of 0.1 and 0.5% (w/v) hydrolyzed (and in some cases common) gelatin was estimated. Results show that the solubility of all drugs is significantly enhanced, especially in the presence of 0.5% gelatin. This gelatin-induced enhancement in drug solubility is higher in the pH in which acidic drugs are less ionized, especially for the less lipophilic acidic drugs (nitrofurantoin, chlorothiazide). In all cases, drug solubility in presence of gelatin is correlated with their aqueous solubility. Therefore, the established relationships between aqueous and gelatin solubility can be employed to derive an estimate of the drug solubility in presence of gelatin once its aqueous solubility is known. With the exception of piroxicam which is highly ionized and phenobarbital which is relatively soluble, there seems to be a tendency for larger gelatin-induced increases in solubility as drug lipophilicity increases or aqueous solubility decreases.