7 research outputs found
An integrated view of theiInfluence of temperature, pressure, and humidity on the stability of trimorphic cysteamine hydrochloride
Get PDFUnderstanding the phase behavior of pharmaceuticals is important for dosage form development and regulatory requirements, in particular after the incident with ritonavir. In the present paper, a comprehensive study of the solid-state phase behavior of cysteamine hydrochloride used in the treatment of nephropathic cystinosis and recently granted orphan designation by the European Commission is presented employing (high-pressure) calorimetry, water vapor sorption, and X-ray diffraction as a function of temperature. A new crystal form (I2/a, form III) has been discovered, and its structure has been solved by X-ray powder diffraction, while two other crystalline forms are already known. The relative thermodynamic stabilities of the commercial form I and of the newly discovered form III have been established; they possess an overall enantiotropic phase relationship, with form I stable at room temperature and form III stable above 37 degrees C. Its melting temperature was found at 67.3 +/- 0.5 degrees C. Cysteamine hydrochloride is hygroscopic and immediately forms a concentrated saturated solution in water with a surprisingly high concentration of 47.5 mol % above a relative humidity of 35%. No hydrate has been observed. A temperature composition phase diagram is presented that has been obtained with the unary pressure temperature phase diagram, measurements, and calculations. For development, form I would be the best form to use in any solid dosage form, which should be thoroughly protected against humidity.Postprint (author's final draft
On central limit theorem for sums of series weakly dependent random variables
No full textThe abstracts (in two languages) can be found in the pdf file of the article.
Original author name(s) and title in Russian and Lithuanian:
Б. Ряуба, О центральной предельной теореме для сумм серий слабо зависимых случайных величин
B. Riauba, Dėl centrinės ribinės teoremos silpnai priklausomų atsitiktinių dydžių serijų sumoms</jats:p
On limit theorems for weakly dependent random variables
No full textThe abstracts (in two languages) can be found in the pdf file of the article.
Original author name(s) and title in Russian and Lithuanian:
Б. Ряуба. О предельных теоремах для слабо зависимых случайных величин
B. Riauba. Ribinių teoremų silpnai priklausomiems atsitiktiniams dydžiams klausimu</jats:p
Central limit theorem for sums of series weakly dependent random variables
No full textThe abstracts (in two languages) can be found in the pdf file of the article.
Original author name(s) and title in Russian and Lithuanian:
Б. Ряуба. Центральная предельная теорема для сумм серий слабо зависимых случайных величин
B. Riauba. Centrinė ribinė teorema silpnai priklausomų atsitiktinių dydžių serijų sumoms</jats:p
An Almost-Markov-Type Mixing Condition and Large Deviations for Boolean Models on the Line
No full text
