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Rheology in Technology of Inorganic Binders
Kosár, Petr ; Másilko, Jiří (referee) ; Zmrzlý, Martin (advisor)
This final thesis deals with the study of rheological behaviour of cement pastes. The introductory part describes the composition of Portland cement. Next, a detailed description of mutual interaction between cement and water and the principle of superplasticizer affection follows. The thesis includes a description of properties and interaction of alumina cement with water as well as rheological properties of suspensions and cement pastes. Finally, the theoretical part provides a survey of the elementary methods and equipment for the evaluation of rheological properties of cement materials. The experimental part includes measurement and evaluation of rheological properties (flow curves, plastic viscosity and yield stress) of cement pastes with different composition. The influences of water-cement ratio, amount of superplasticizer and the kind of cement on rheological properties of cement pastes are compared here.
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Dissolution of a drug from thin films based on plasticized PLGA derivatives
Kodytková, Simona ; Šnejdrová, Eva (advisor) ; Paraskevopoulou, Anna (referee)
CHARLES UNIVERSITY Faculty od Pharmacy in Hradec Kralove Department od Pharmaceutical Technology Author: Simona Kodytková Title od Diploma thesis: Dissolution of a drug from thin films based on plasticized PLGA derivatives Supervisor: PharmDr. Eva Šnejdrová, Ph.D. The aim of the presented work was to formulate liquid systems for the formulation of in situ thin films (FFS) based on copolymers D,L-lactic and glycolic acid (PLGA) and to study the effect of a combination of salicylic acid and methyl salicylate in film and the effect of their various concentrations on dissolution profiles. The theoretical section summarizes the general knowledge about the characteristics, substances used to formulate FFS and methods for their testing. In the experimental section, liquid systems forming in situ films by solvent evaporation were prepared, based on a linear or branched PLGA polymer containing salicylic acid as a poor water soluble drug, and methyl-salicylate as a multifuctional plasticizer, at different concentrations. The solubility test of salicylic acid, methyl salicylate and their mixtures, and dissolution tests of drug and plasticizer in phosphate buffer buffer pH 5.5 at 37 řC were performed. Salicylate analysis was performed by HPLC. Based on the results, it can be stated that faster dissolution of...
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Acyclovir release from mucoadhesive matrices
Šišáková, Lenka ; Šnejdrová, Eva (advisor) ; Dittrich, Milan (referee)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Student: Lenka Šišáková Supervisor of Diploma thesis: PharmDr. Eva Šnejdrová, Ph.D. Title of Diploma thesis: Aciclovir release from mucoadhesive matrices The aim of this diploma thesis was the study of the mucoadhesive parameters of plasticized oligoester of lactic acid and glycolic acid and 3% mannitol as a branching monomer. Knowledge of dissolution testing of drug release from dosage form, principal theories and mechanisms of mucoadhesion and mucoadhesion testing of adhesive formulation is described in theoretical part. Matrices formed from terpolymer of D,L-lactic acid, glycolic acid branched with mannitol and 5 % aciclovir were examined in the experimental part. Triethylcitrate (TEC), ethylpyruvate (EP), methylsalicylate (MS) and ethylsalicylate (ES) were used as plasticizers. Dissolution test has been done. Hydrated mucin from porcine stomach was used as a base. Phosphate-citrate buffer pH 7.4 was used as a dissolution medium. Dissolution was defined as a quantity of released aciclovir in to the dissolution medium after 15, 30, 60 and 90 minutes. The quantity of the released aciclovir was defined by a spectrophotometry. In 90 minutes was released 43 % of aciclovir from the matrice...
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Biodegradable solid dispersion for application to mucous membranes
Janáková, Gabriela ; Šnejdrová, Eva (advisor) ; Dittrich, Milan (referee)
1. ABSTRAKT CHARLES UNIVERSITY Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Name of the student: Mgr. Gabriela Janáková Title of diploma thesis: Biodegradable solid dispersion for application to mucous membranes Consultant: PharmDr. Eva Šnejdrová, Ph.D. The aim of this work was to formulate solid dispersions for application to the mucosa and the skin in the form of a thin film and to study their dissolution properties. Solid dispersions were comprised of biodegradable copolymers of lactic acid and glycolic branched using 3% (3P) or 5% (5P) of pentaerythriol. They were prepared by a melting method with the addition of ethyl salicylate (ES) as a prodrug and plasticizer and optionally incorporating salicylic acid. As a dissolution medium phosphate buffer pH 7.4 was used. The theoretical part focuses on biodegradable polymers and solid dispersions. A faster course of salicylate release was observed in case of the polyester with higher molecular weight, higher branching ratio, and higher glass transition temperature. Higher content of ethyl salicylate slowed down salicylate release. After the incorporation of 5% salicylic acid into the polyester plasticized by ethyl salicylate, there was no expected elongation of salicylate release. The solid dispersion based on polyester...
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Acyclovir release from mucoadhesive matrices
Šišáková, Lenka ; Šnejdrová, Eva (advisor) ; Dittrich, Milan (referee)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Student: Lenka Šišáková Supervisor of Diploma thesis: PharmDr. Eva Šnejdrová, Ph.D. Title of Diploma thesis: Aciclovir release from mucoadhesive matrices The aim of this diploma thesis was the study of the mucoadhesive parameters of plasticized oligoester of lactic acid and glycolic acid and 3% mannitol as a branching monomer. Knowledge of dissolution testing of drug release from dosage form, principal theories and mechanisms of mucoadhesion and mucoadhesion testing of adhesive formulation is described in theoretical part. Matrices formed from terpolymer of D,L-lactic acid, glycolic acid branched with mannitol and 5 % aciclovir were examined in the experimental part. Triethylcitrate (TEC), ethylpyruvate (EP), methylsalicylate (MS) and ethylsalicylate (ES) were used as plasticizers. Dissolution test has been done. Hydrated mucin from porcine stomach was used as a base. Phosphate-citrate buffer pH 7.4 was used as a dissolution medium. Dissolution was defined as a quantity of released aciclovir in to the dissolution medium after 15, 30, 60 and 90 minutes. The quantity of the released aciclovir was defined by a spectrophotometry. In 90 minutes was released 43 % of aciclovir from the matrice...
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Effect of plasticization on rheological properties of oligoester of lactic acid and glycolic acid branched with dipentaerythritol
Bílková, Klára ; Šnejdrová, Eva (advisor) ; Dittrich, Milan (referee)
CHARLES UNIVERSITY IN PRAGUE Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical technology Name of the student: Klára Bílková Title of diploma thesis: Influence of plastification on rheological properties of oligoester of lactic acid and glycolic acid branched with dipentaerythritole Consultant: PharmDr. Eva Šnejdrová, Ph.D. The aim of this diploma thesis was the study of rheological properties of the oligoester of DL-lactic and glycolic acids branched with 1% of dipenthaerythritol (1D) and plasticized with 6 various plasticizers in increasing concentrations. Theoretical part was devoted to fundamentals of rheology and measurements of viscosity using rotational viscometers. It describes basic types and constructions of rotational rheometers and summarizes basic facts about bioadhesion and use of rheological method for assessment of bioadhesion. There were prepared matrices from oligoester 1D and plasticizers in concentrations of 20 %, 30 % and 40 % in the experimental part. These plasticizers were tested: ethyl pyruvate, ethyl salicylate, methyl salicylate, triacetin, tributyrin and triethyl citrate. Rheological properties were examinated at 37 řC using spindle viscometer and at 37 řC and 50 řC using rotational rheometer. Rheograms were used to characterize flow properties of tested...
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Aciclovir release from mucoadhesive polyester matrices
Jakubíková, Hana ; Šnejdrová, Eva (advisor) ; Dittrich, Milan (referee)
CHARLES UNIVERSITY IN PRAGUE Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical technology Name of the student: Hana Jakubíková Title of diploma thesis: Aciclovir release from mucoadhesive polyester matrices Consultant: PharmDr. Eva Šnejdrová, Ph.D. The aim of this diploma thesis was to investigate aciclovir release from polyesters of lactic acid and glycolic acid branched with mannitol, pentaerythritol, dipentaerythritol and tripentaerythritol, and plasticized using ethyl pyruvate or methyl salicylate. Theoretical part sums up the application possibilities of mucoadhesive preparations. Experimental part of thesis deals with aciclovir release from polyester matrices applied on mucous substrate. Short term dissolution experiments of aciclovir were carried out in phosphate citrate buffer of pH 7, 4 at 37 řC. Mucus from porcine stomach was used as model substrate. The amount of aciclovir released was determined spectrophotometrically at 256 nm contrary to a blank sample, and also using HPLC method. Dissolution of aciclovir was affected by molar mass of polyester, and by the type and concentration of plasticizer. Polyester branched with 3 % of tripentaerythritol, and plasticizes by 40 % of methyl salicylate was found to be most suitable carrier of aciclovir for topical application on...
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Rheological properties of White Soft Paraffin
Hánová, Anna ; Šnejdrová, Eva (advisor) ; Šiška, Bedřich (referee)
CHARLES UNIVERSITY IN PRAGUE Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical technology Name of the student: Anna Hánová Title of diploma thesis: Rheological properties of White Soft Paraffin Consultant: PharmDr. Eva Šnejdrová, Ph.D. This diploma thesis deals with the evaluation of consistency and rheological properties of the Soft Paraffin after viscosity modification by either Liquid or Solid Paraffin. The theoretical part focuses the characteristics and application of the hydrocarbon excipients, their use in pharmacy and comparison with other substances, rheological properties of semisolids and their consistency. Consistency by penetrometry according the Czech Pharmacopoeia 2009 and rheological properties using Kinexus rheometer were measured. Consistency of Soft Paraffin was significantly influenced with 5 % of Liquid Paraffin and 10 % of Solid Paraffin. The result of consistency assessment is significantly influenced by the method of the samples preparation. Rheograms and viscosity curves was constructed. Plastic systems were described in detail by the parameters of power law model and yield stress value. The addition of 5 % of Liquid Paraffin to the Soft White Paraffin caused the decrease of the coefficient of consistency and the flow index. A further addition of Liquid...
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Rheology in Technology of Inorganic Binders
Kosár, Petr ; Másilko, Jiří (referee) ; Zmrzlý, Martin (advisor)
This final thesis deals with the study of rheological behaviour of cement pastes. The introductory part describes the composition of Portland cement. Next, a detailed description of mutual interaction between cement and water and the principle of superplasticizer affection follows. The thesis includes a description of properties and interaction of alumina cement with water as well as rheological properties of suspensions and cement pastes. Finally, the theoretical part provides a survey of the elementary methods and equipment for the evaluation of rheological properties of cement materials. The experimental part includes measurement and evaluation of rheological properties (flow curves, plastic viscosity and yield stress) of cement pastes with different composition. The influences of water-cement ratio, amount of superplasticizer and the kind of cement on rheological properties of cement pastes are compared here.
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