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Biomedical subjects

Janina Szulc

Publications and source records attributed to Janina Szulc.

3 recordsLinked to original sources

[Liposomes--therapeutic progress and technological problems].

Liposomes represent globular vesicles composed of an aqueous core and one or several phospholipid bilayers. They can encapsulate hydrophilic or lipophilic drugs used in therapy and diagnostic imaging. Liposomes provide protection of the active substances, sustained or controlled release and also targeted delivery of drugs to specific cells, tissues, organs. Easy oxydation of phosphatidylcholin (lecithin)--the main membrane component--is the limitation of the introduction of liposomes to the medicinal practice in a broader scale. Unsatisfying chemical stability of lecithin has an unfavourable influence on drug and liposome stability. Liposomes decompose during storage and leakage of the encapsulated drug occurs. A review of advantages of application of liposomes in medicine and methods of increasing their stability was presented.

Antineoplastic Combined Chemotherapy Protocols↗

The effect of cryoprotectants on the physical properties of large liposomes containing sodium diclofenac.

Large liposomes (1-10 microm) containing sodium diclofenac were prepared and lyophilized using lactose or mannitol (7.5% in respect to the lipid content) as cryoprotectants. The physical studies of liposomes were performed during 30 days of storage in a dry or resuspended form. Lyophilization of large liposomes and storage in the dry form at 5 degrees C increases their physical stability. Lactose is a cryoprotectant which does not influence changes of properties of liposomes regarding their size, encapsulation efficacy and release rate. Large liposomes lyophilized in the presence of mannitol tend to increase in size and encapsulation efficacy, but the lipid bilayers are stabilized and less permeable to the drug.

Cryoprotective Agents↗

Feasibility of the Ph.Eur. flow-through cell for dissolution testing of the compounded rectal suppositories containing indomethacin or sodium diclofenac.

Ph.Eur. and BP have introduced a dissolution apparatus for suppositories. Suitability of the apparatus for quality control of indomethacin or sodium diclofenac (100 mg) compounded suppositories was evaluated and the effect of the type of suppository base on dissolution profiles was studied. The fastest and most reproducible release profiles were observed for hydrophilic base (macrogols). More than 80% of the drug was released during 60 min, while after 350 min 18.5-50% of the total amount was released from lipophilic bases (Witepsol and Adeps solidus). The results demonstrate that slow and non-reproducible release occurs when the lipophilic suppository base does not melt. The feasibility of the test for the formulations, which do not melt during the procedure, is questionable.

Anti-Inflammatory Agents, Non-Steroidal↗