ABSTRACT
ABSTRACT: Slow-growth tissue culture allows in vitro conservation of plant genetic resources and is a complementary technique to conventional preservation methods. The objective of this study was to evaluate the effect of the culture medium supplemented with sucrose, mannitol and sorbitol osmotic agents on the induction of in vitro slow growth of A. cearensis, seeking to establish alternative techniques for ex situ conservation of the species. Plants with age of 10 days were inoculated in woody plant medium (WPM) supplemented with different concentrations of sucrose (87.64, 131.46, 175.28 or 262.92 mM) combined with mannitol or sorbitol at varying concentrations (0.0, 43.8, 65.73, 87.64 or 131.46 mM), solidified with 0.7% agar. The following parameters were evaluated: survival percentage, number of senescent leaves, aerial part length, root length, aerial part dry mass, root dry mass; and number of shoots. The conservation of A. cearensis was viable for up to 300 days in WPM supplemented with 262.92 mM of sucrose or the combination of 87.64 mM of sucrose with 43.80 mM of mannitol, because besides achieving a survival percentage greater than 55.0%, the plants conserved in these media presented normal development and the best appearances, with predominance of uniform green leaves during the storage process.
RESUMO: A cultura de tecidos, através do crescimento mínimo, possibilita a conservação in vitro dos recursos genéticos vegetais, tornando-se uma técnica complementar aos métodos convencionais de conservação. O objetivo deste estudo foi avaliar o efeito do meio de cultura suplementado com sacarose, manitol e agentes osmóticos sorbitol na indução de crescimento mínimo in vitro de A. cearensis, buscando estabelecer técnicas alternativas para conservação ex situ da espécie. Plantas com 10 dias foram inoculadas em meio de cultura WPM suplementado com diferentes concentrações de sacarose (87,64; 131,46; 175,28 e 262,92 mM) combinado com manitol ou sorbitol nas concentrações (0,0; 43,8; 65,73; 87,64 e 131,46 mM), solidificados com 0,7% de ágar. Foram avaliados a porcentagem de sobrevivência, número de folhas senescentes, comprimento da parte aérea, comprimento da raiz, massa seca da parte aérea, massa seca da raiz e número de brotos. A conservação de A. cearensis mostrou-se viável até 300 dias, em meio de cultura WPM suplementado com 262,92 mM de sacarose ou na combinação de 87.64 mM de sacarose com 43.80 mM de manitol. Assim sendo, além de apresentarem porcentagem de sobrevivência acima de 55.0%, as plantas conservadas nesses meios apresentaram um desenvolvimento normal e com melhores aparências com predomínio de folhas verdes uniformes ao longo do processo de armazenamento.
ABSTRACT
OBJECTIVE: Push-pull osmotic pump (PPOP) is one of conventional osmotic pump systems, which has been widely investigated for formulation development of BCS Ⅱ APIs. However, there is still a lack of experimental data based discussions for some key formulation factors of PPOP. Thus, to investigate some key formulation factors by designed experiments and tried to give some recommendations for those considerations in industrial formulation development. METHODS: Nifedipine was selected as the model drug in this study. The hydration & swell rate and strength of three grades of commercialized high molecular weight polyethylene oxide (PEO) were evaluated via swelling volume change using a home-made apparatus and via compression force using texture analyzer, respectively. The effect of different film coating thickness, proportion of osmotic agent in push layer, and ratios of push layer to pull layer were investigated by drug dissolution using USP apparatus Ⅱ as well. RESULTS: The swelling rate and strength of three grades of high molecular weight PEO (POLYOXTM 301, POLYOXTM Coagulant, and POLYOXTM 303) enhanced along with the molecular weight. The difference of swelling rate is not significant (P>0.05), but that of swelling gel strength is significant (P<0.05). Adding osmotic agent, e.g. NaCl, could significantly improve the swelling rate. Thicker coating membrane retarded drug release and as the coating thickness was higher than 180 μm, it caused incomplete drug release (<90%). When the NaCl proportion in push layer was between 10% and 30 %, there was no significant differences among drug dissolution profiles. However, when the percent of NaCl content in push layer was above 50%, the drug release from PPOP became slower and more incomplete (<90%). CONCLUSION: The ratio of DL/PL has significant impact on drug release. The lower the ratio of DL/PL resulted in faster and more complete drug release. For nifedipine case, the ratio of 2 was recommended.
ABSTRACT
The present work aimed to evaluate glycerol, maltodextrin, polydextrose and sorbitol for the osmotic dehydration of yacon for diabetics, keeping its properties as prebiotic. Osmotic dehydration was carried out using a yacon to 33% concentrated syrup weight ratio of 1:12, with magnetic stirring at 23ºC and atmospheric pressure. The best results were achieved for glycerol and sorbitol with 80 ± 4% and 81± 1% of water removal and increase of 3.73 ± 0.11 and 4.30 ± 0.16 times in total soluble solids respectively. Maltodextrin did not promote dehydration.
ABSTRACT
In recent years, oral controlled release (CR) system is most acceptable dosage form by the patients. Drugs having short biological half-life and poor water solubility are the suitable candidate for development of CR system. They include dosage forms for oral and transdermal administration as well as injectable and implantable systems. For most of drugs, oral route remains as the most acceptable route of administration. Certain molecules may have low oral bioavailability because of solubility or permeability limitations. Development of an extended release dosage form also requires reasonable absorption throughout the gastro-intestinal tract (GIT). Among the available techniques to improve the bioavailability of these drugs fabrication of osmotic drug delivery system is the most appropriate one. The release of drug(s) from osmotic systems follows zero order. It is mainly governed by various formulation factors such as solubility and osmotic pressure of the core component(s), size of the delivery orifice, and nature of the rate-controlling membrane. The present review highlights an overview of OCDDS. And new technologies, fabrication and recent clinical research in osmotic drug delivery. Further, the challenges of these technologies and its future perspective are also discussed at length.