Zdenek Zatloukal

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The application of eye drops is known to be problematic due to the high variability of eye drop volume, the low capacity of the precorneal area resulting in an optimal drop volume of about 20 microl, and the risk of adverse systemic effects of drugs due to systemic absorption via the nasal mucosa. While dropper tip design and the surface activity of the(More)
In this work, penetrometry with a sphere was employed to study the flow properties of non-consolidated pharmaceutical powder excipients: sodium chloride, sodium citrate, boric acid, and sorbitol. In order to estimate flow rate, the pressure of penetration in Pascals was used. Penetrometry measurement with a sphere requires modification of the measurement(More)
The application of eye drops from flexible dropper bottles fitted with different types of dropper tips is associated with the high variability of eye drop weights. The aim of this report was to investigate the simultaneous effect of three factors influencing the mean weight of drops dispensing from two plastic dropper tips. Using a designed experiment(More)
Hydration of polyhydroxyethylmethacrylate (PHEMAs hydrogel with aqueous solutions of medicinal substance) renders it possible to deposit medicinal substances within the hydrogel. At the same time the concentration of the medicinal substances in the hydrogel is higher than their concentration in the hydrating solution. For the nonspecific interactions, which(More)
A comparison of capillary and rotational viscometry of gentle pseudoplastic solutions of hypromellose (HPMC 4000) by using only single-point value of viscosity is difficult. Single-point comparison becomes topical in consequence to the pharmacopoeial requirement that the apparent viscosity of 2% hypromellose solution should be read at the shear rate of(More)
  • Z Zatloukal
  • 2004
The precision of dosing of powder drugs in piece dosage forms can be theoretically forecast by means of statistical principles of variability of random mixtures, the use of which for this purpose has been traditionally examined. The present critical review of the literature of the subject is primarily focused on random mixing of powder mixtures, their(More)
  • Z Zatloukal
  • 2000
Using a hydrated filtering membrane, the rate of hydration of the lyophilized xerogel hydroxypropylmethyl cellulose (HPMC) 4000 with an isotonic solution of sodium chloride was examined. The presence of the electrolyte influences the kinetics of diffuse hydration linearized by the root of time. Sodium chloride or pilocarpinium chloride significantly(More)
In this article, the influence of electrolytes on the viscosity of sterilized hydrogels containing 60 g/L of hydroxypropyl methylcellulose (HPMC 4000) was investigated. The electrolytes mostly used in ophthalmics were sodium chloride, pilocarpine hydrochloride, atropine sulphate, and scopolamine hydrobromide. The hydrogels were prepared by using stationary(More)