| 91. |
- Velaga, Sitaram, et al.
(författare)
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Supercritical fluids crystallisation of budesonide and flunisolide
- 2002
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Ingår i: Pharmaceutical research. - 0724-8741 .- 1573-904X. ; 19:10, s. 1564-1571
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Budesonide and flunisolide anhydrate were crystallized using the solution enhanced dispersion by supercritical fluids (SEDS) technique. The aim was to investigate the possibility of preparing different pure polymorphs.Methods: 0.25% w/v solutions of each drug were prepared from acetone and methanol. Operating conditions were 40-80°C and 80-200 bars. The flow rate of drug solution was 0.3 mL/min and that of CO2 was 9-25 mL/min. Sample characterizations included differential scanning calorimetry, X-ray powder diffraction, variable temperature X-ray diffraction, scanning electron microscopy, and solubility studies.Results: The particle morphology of budesonide was dependent on the nature of the solvent. SEDS processing of flunisolide with acetone at 100 bars resulted in the formation of polymorphic mixtures at 80°C and a new polymorph III at 60 C and 40°C. With methanol at 100 bars another new polymorph IV was formed with different particle morphology at 80°C and a polymorphic mixture at 60°C.Conclusion: Using the SEDS, microparticles of crystalline budesonide were prepared and new polymorphs of flunisolide were produced. Particle characteristics were controlled by the temperature, pressure and relative flow rates of drug solution and CO2.
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| 92. |
- Velaga, Sitaram, et al.
(författare)
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Supercritical fluids processing of recombinant human Growth Hormone
- 2005
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Ingår i: Drug Development and Industrial Pharmacy. - 0363-9045 .- 1520-5762. ; 31:2, s. 135-149
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to investigate the feasibility of precipitating recombinant human growth hormone (hGH) from aqueous solutions using conventional and modified techniques of solution-enhanced dispersion (SEDS) by supercritical fluids. The study investigated the effect on hGH stability of adding isopropanol either as a cosolvent with the original aqueous protein solution (conventional process) or to the supercritical carbon dioxide before mixing with the aqueous protein solution (modified process). The influence of the addition of sucrose (with or without isopropanol) on the precipitation behavior and stability of the protein was also studied. Experiments were performed under various processing conditions (pressure 100-200 bars and temperature 40-50 degrees C), and with various flow rates and solution compositions (CO2/isopropanol and protein solution). Bioanalytical characterization of the resulting powders involved spectrophotometry, sodium dodecyl sulfate-polycrylamide gel electrophoresis, reverse-phase high performance liquid chromatography (RP-HPLC), and size exclusion chromatography. Solid-state characterization was performed using differential scanning calorimetry, X-ray powder diffraction, scanning electron microscopy, and Karl Fischer techniques. Results showed that with both conventional and modified methods, under optimum processing conditions, the presence of sucrose in the solution decreased the destabilizing effects of the solvent and/or process on the structure of hGH. More hGH was dissolved from the precipitated powders containing sucrose than from those containing only isopropanol. Reverse-phase HPLC indicated that about 94% of the hGH was recovered in its native form. The proportion of dimers and oligomers was reduced in the presence of sucrose; about 92% of the soluble protein was present in monomer form under optimal conditions. The remaining undissolved protein was in monomeric form. The precipitated powders were amorphous, containing particulate aggregates in the size range 1-6 microm with 5-10% residual moisture content. In conclusion, hGH was successfully precipitated from aqueous solution using SEDS technology. The presence of sucrose in the protein solution promoted the precipitation of hGH and reduced aggregation and improved dissolution.
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| 93. |
- Vuddanda, Parameswara Rao, et al.
(författare)
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Boswellic acid – Medicinal use of an ancient herbal remedy
- 2016
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Ingår i: Journal of Herbal Medicine. - : Elsevier BV. - 2210-8033. ; 6:4, s. 163-170
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Forskningsöversikt (refereegranskat)abstract
- Boswellic acid (BA) is an ancient herbal drug prescribed in the Indian traditional medicine systems (Ayurveda) for treatment of coughs, colds, hoarseness, bronchitis, asthma, dyspnea and diarrhea. Current research suggests it also has therapeutic potential in modern medical practice. Therefore, it is of interest to the research community to consolidate the preclinical and clinical findings on BA. The aim of this review was to comprehensively cover the plant sources, phytochemistry and physicochemical properties of BA along with its medicinal properties, safety, toxicity, and regulatory status. The review also discussed the challenges associated with drug delivery and some feasible approaches for addressing these. Four electronic databases (Scifinder, Unbound Medline, PubMed and Science Direct) and two internet search engines (Scirus and Google Scholar) were extensively searched without any time constraint.The many studies discussed in the review indicated therapeutic potential for BA in the treatment of a range of chronic diseases including arthritis, cancer, asthma and diabetes. It is hoped that this review will help researchers identify relevant research questions leading to the development of effective formulations and a better understanding of the safety of BA, with the aim of promoting it as a mainstream treatment for various diseases in clinical practice.
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| 94. |
- Vuddanda, Parameswara Rao, et al.
(författare)
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Electrospun nanofiber Mats for ultrafast release of ondansetron
- 2016
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Ingår i: Reactive & functional polymers. - : Elsevier BV. - 1381-5148 .- 1873-166X. ; 99, s. 65-72
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Tidskriftsartikel (refereegranskat)abstract
- Nanofiber mats or films are promising platforms that can offer unique opportunities in oromucosoal drug delivery. However, the conventional film forming technologies are unable to produce mats with unique internal microstructure and properties. Thus, the present study was aimed to develop electrospun nanofiber mats of a model drug -ondansetron hydrochloride (OND) for ultrafast drug release. Polyvinyl alcohol (PVA), a water soluble synthetic polymer was used in the preparation of nanofiber mats and casting film. The OND nanofiber mats and conventional films were prepared by electrospinning and casting methods, respectively. Different electrospinning process variables (feed rate, electric voltage and tip to collector distance) were investigated. Nanofiber mats and casted films were characterized using Scanning electron microscopy (SEM), Atomic force microscopy (AFM), Differential scanning calorimetry (DSC), Powder X-ray diffraction (PXRD), and Attenuated total reflection – Fourier transform infrared spectroscopy (ATR-FTIR). The folding endurance, drug content, wetting behaviour and disintegration properties and in-vitro drug release studies were also performed.The SEM and AFM had revealed that the nanofiber mats were formed with smooth uniform texture. Solid state studies indicated that the OND was in amorphous state and uniformly dispersed in PVA mats and a film. The electrospun nanofiber mat and casted film of OND showed sufficient mechanical properties. Wet sponge method suggested that OND nanofiber mats were simultaneously wetted and disintegrated within 10 s, which is ultrafast compared to casted films. The total amount of OND was released in 90 s (1.5 min) and 1800 s (30 min) from OND-PVA electrospun nanofiber mats and casted film, respectively. OND nanofiber mats can be promising alternatives to existing solid dosage forms for ultrafast release of drugs.
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| 95. |
- Vuddanda, Parameswara Rao, et al.
(författare)
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Personalisation of warfarin therapy using thermal ink-jet printing
- 2018
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Ingår i: European Journal of Pharmaceutical Sciences. - : Elsevier. - 0928-0987 .- 1879-0720. ; 117, s. 80-87
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Tidskriftsartikel (refereegranskat)abstract
- Warfarin is a widely used anticoagulant that is critical in reducing patient morbidity and mortality associated with thromboembolic disorders. However, its narrow therapeutic index and large inter-individual variability can lead to complex dosage regimes. Formulating warfarin as an orodispersible film (ODF) using thermal ink-jet (TIJ) printing could enable personalisation of therapy to simplify administration. Commercial TIJ printers are currently unsuitable for printing the milligram dosages, typically required for warfarin therapy. As such, this study aimed to modify a commercial TIJ printing system to formulate personalised warfarin ODFs containing therapeutic dosages. A TIJ printer was modified successfully with the printer functionality intact; the substrate (paper) rolling mechanism of the printer was replaced by printing onto a stationary stage. Free film substrates were composed of hydroxypropyl methylcellulose (20%w/w) and glycerol (3%w/w). The resulting ODFs were characterised for morphology, disintegration, solid-state properties and drug content. Printed film stability was assessed at 40 °C/75% relative humidity for 30 days. Therapeutic warfarin doses (1.25 and 2.5 mg) were successfully printed onto the film substrates. Excellent linearity was observed between the theoretical and measured dose by changing the warfarin feed concentration (R2 = 0.9999) and length of the print objective, i.e. the Y-value, (R2 = 0.9998). Rapid disintegration of the ODFs was achieved. As such, this study successfully formulated personalised warfarin ODFs using a modified TIJ printer, widening the range of applications for TIJ printing to formulate narrow therapeutic index drugs.
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| 96. |
- Yang, Mingshi, et al.
(författare)
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Characterisation of salmon calcitonin in spray-dried powder for inhalation : effect of chitosan
- 2007
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Ingår i: International Journal of Pharmaceutics. - : Elsevier BV. - 0378-5173 .- 1873-3476. ; 331:2, s. 176-81
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Tidskriftsartikel (refereegranskat)abstract
- Salmon calcitonin (sCT) powders suitable for inhalation, containing chitosan and mannitol as absorption enhancer and protection agent, respectively, were prepared using a spray-drying process. The effect of chitosan on physicochemical stability of sCT in the dry powder was investigated by different analytical techniques. High-performance liquid chromatography (HPLC) analysis indicated that sCT was chemically stable upon spray-drying. With the proportion of chitosan in spray-drying formulation being increased, dissolution of sCT from the dry powders was decreased both in phosphate buffer and acetate buffer. The thioflavine T fluorescence assay showed that no fibrils were present in the spray-dried powder. However, sCT partly fibrillated in the phosphate buffer, but not in acetate buffer. Fourier transform infrared (FTIR) spectra showed that the secondary structure of sCT was slightly changed in the dry powder, yet no aggregate signal was observed. Circular dichroism analysis indicated that the structure of sCT in an aqueous formulation was slightly altered by addition of chitosan. Nevertheless, recovery of sCT was not influenced by chitosan in the aqueous formulation as indicated by HPLC analysis. This study suggested that sCT, in absence of any additives, was stable during the spray-drying process under certain conditions. Addition of chitosan affects recovery of sCT from spray-dried powders, which may be due to formation of a partially irreversible complex between the protein and chitosan during the spray-drying process.
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| 97. |
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