Microparticles, aimed for oral protein and peptide drug delivery, were prepared via emulsion cross-linking using citric acid as cross-linker and polyglycerol polyricinoleate as surfactant. A comparative study of the interaction between chitosan and citric acid and its effect on the resulting microparticle properties was performed using different chitosan-to-cross-linker mass ratios and pH-values during fabrication of the microparticles. Non-cross-linked and cross-linked microparticles were studied in terms of size (4–12 μm), zeta potential (−15.7 to 12.8 mV), erosion (39.7–75.6%), a model protein encapsulation efficiency (bovine serum albumin) (6.8–27.6%), and loading capacity (10.4–40%). Fourier transform infrared spectroscopy and X-ray diffraction confirmed the ionic interaction between the protonated amine groups of chitosan and the carboxylate ions of the cross-linking agent. Scanning electron microscopy revealed that the non-cross-linked microparticles had an uneven shape with wrinkled surfaces, while the cross-linked formulations were spherical in shape with smooth surfaces. On the basis of these data, the role of the surfactant and microparticle structure on the release mechanism was proposed. Control of the microparticle shape and release mechanisms is expected to be crucial in developing carriers for the controlled delivery of proteins and peptides.

New water-in-oil microemulsion, based on paraffin oil, polyglycerol polyricinoleate and Tween 80, has been formulated and used as encapsulation matrix for doxorubicin. Drug release features and in vitro cytotoxicity for the formulation has been evaluated.

The chitosan microspheres were prepared by an emulsion-ionic cross-linking method; the interaction between chitosan and an anionic cross-linker was studied, and the average size, surface morphology, insulin sorption and drug release profile of formulated microspheres were evaluated.

Sanguinarine is a plant alkaloid with relatively low toxicity and high antiangiogenic, antitumour and antiviral potential. In order to increase its bioavailability and effectiveness, sanguinarine liposomes were prepared by a reverse phase evaporation method and characterised. Dynamic light scattering showed mean liposome size of 65 ± 11 nm, zeta-potential equal to -54 ± 1.2 mV, and polydispersity index equal to 0.26. The encapsulation efficiency was 78.6 ± 5.1%. The study on experimental models showed a prolonged sanguinarine release from liposome preparations. Liposomal sanguinarine showed dose-dependent cytotoxic activity in vitro on B16 (murine melanoma) and HeLa (human cervical carcinoma) cell lines. The highest cytotoxicity was observed on B16 cell line (IC50 6.5 μM). HeLa cell line cytotoxicity was relatively lower, equal to 8.03 μМ. Compared with free sanguinarine, liposomal sanguinarine may have advantages for in vivo anticancer therapy, due to its lower toxicity and 'passive targeting' as a result of enhanced permeability of tumour vessels.