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Gas therapy has been proven to be a promising and advantageous treatment option for cancers. Studies have shown that nitric oxide (NO) is one of the smallest structurally significant gas molecules with great potential to suppress cancer. However, there is controversy and concern about its use as it exhibits the opposite physiological effects based on its levels in the tumor. Therefore, the anti-cancer mechanism of NO is the key to cancer treatment, and rationally designed NO delivery systems are crucial to the success of NO biomedical applications. This review summarizes the endogenous production of NO, its physiological mechanisms of action, the application of NO in cancer treatment, and nano-delivery systems for delivering NO donors. Moreover, it briefly reviews challenges in delivering NO from different nanoparticles and the issues associated with its combination treatment strategies. The advantages and challenges of various NO delivery platforms are recapitulated for possible transformation into clinical applications.
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AIM: To investigate the absorption of helicid in different segments of intestine based on rat everted intestine sac model. METHODS: To establish a high-performance liquid chromatography method for simultaneous determination of helicid and its metabolite. Krebs-ringer solution containing helicid was added to everted intestine sacs of different segments (duodenum, Jejunum, ileum and colon). Drug concentration in sacs was determined at different time points (5, 10, 15, 30, 45, 60, 75, 90 min). Adsorptions of helicid in four intestinal segments were compared. RESULTS: This high-performance liquid chromatography was successfully applied to the simultaneous determination of helicid and its metabolite. Absorption of helicid was rapid and time-dependent. The absorption and metabolism of helicid in duodenum segment were higher than these in other segments. CONCLUSION: The duodenum segment is the main site of segmental absorption and metabolism of helicid. This is the first report on intestinal segment metabolism of helicid.
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The aim of the present study was to increase distribution of yuanhuacine in the lungs and achieve the purpose of reducing toxicity and increasing efficiency.Therefore,yuanhuacine was designed to be dry powder inhalers innovatively and directly delivered to the lungs.Accordingly,inhaled lactose was used as a carrier to adsorb yuanhuacine on the surface of lactose.Fine particle fraction (FPF) was utilized as evaluation index to filtrate the optimal prescription for pulmonary administration.Besides,an UHPLC-MS/MS method was established for the analysis of heart,liver,spleen,lung,kidney,brain and reproductive system of rats.Intravenous injection was taken as reference to investigate the distribution of yuanhuacine and calculate relevant targeting parameters.The experimental result indicated that the prescription (rough lactose ∶fine lactose =10 ∶ 1) has the highest FPF,which can be chosen as the most suitable prescription for pulmonary administration of yuanhuacine.Moreover,by comparing the distribution of yuanhuacine through pulmonary administration and intravenous injection,it was found that the concentration of yuanhuacine in the lung tissue was greatly increased by pulmonary administration,which decreased the distribution in heart,liver,spleen,kidney,brain and reproductive system,thus sequentially reducing the toxicity in other tissues and increased the efficiency.
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Huperzine A (Hup-A) is a poorly water-soluble drug with low oral bioavailability. A self-microemulsifying drug delivery system (SMEDDS) was used to enhance the oral bioavailability and lymphatic uptake and transport of Hup-A. A single-pass intestinal perfusion (SPIP) technique and a chylomicron flow-blocking approach were used to study its intestinal absorption, mesenteric lymph node distribution and intestinal lymphatic uptake. The value of the area under the plasma concentration-time curve (AUC) of Hup-A SMEDDS was significantly higher than that of a Hup-A suspension (<0.01). The absorption rate constant () and the apparent permeability coefficient () for Hup-A in different parts of the intestine suggested a passive transport mechanism, and the values ofandof Hup-A SMEDDS in the ileum were much higher than those in other intestinal segments. The determination of Hup-A concentration in mesenteric lymph nodes can be used to explain the intestinal lymphatic absorption of Hup-A SMEDDS. For Hup-A SMEDDS, the values of AUC and maximum plasma concentration () of the blocking model were significantly lower than those of the control model (<0.05). The proportion of lymphatic transport of Hup-A SMEDDS and Hup-A suspension were about 40% and 5%, respectively, suggesting that SMEDDS can significantly improve the intestinal lymphatic uptake and transport of Hup-A.
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In this paper, chloramphenicol was selected as a model drug to prepare in situ gels. The intrinsic dissolution rate of chloramphenicol from in situ gel was evaluated using the surface dissolution imaging system. The results indicated that intrinsic dissolution rate of chloramphenicol thermosensitive in situ gel decreased significantly when the poloxamer concentration increased. The addition of the thickener reduced the intrinsic dissolution rate of chloramphenicol thermosensitive gel, wherein carbomer had the most impact. Different dilution ratios of simulated tear fluid greatly affected gel temperature, and had little influence on the intrinsic dissolution rate of chloramphenicol from the thermosensitive in situ gel. The pH of simulated tear fluid had little influence on the intrinsic dissolution rate of chloramphenicol thermosensitive in situ gel. For the pH sensitive in situ gel, the dissolution rates of chloramphenicol in weak acidic and neutral simulated tear fluids were slower than that in weak alkaline simulated tear fluid. In conclusion, the intrinsic dissolution of chloramphenicol from in situ gel was dependent on formulation and physiological factors. With advantages of small volume sample required and rapid detection, the UV imaging method can be an efficient tool for the evaluation of drug release characteristics of ophthalmic in situ gel.
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The purpose of this study is to investigate the applicability of a natural swelling matrix derived from boat-fruited sterculia seed (SMS) as the propellant of osmotic pump tablets. The sugar components, static swelling, water uptake and viscosity of SMS were determined and compared with that of polythylene oxide (WSR-N10 and WSR-303). Both ribavirin and glipizide were used as water-soluble and water-insoluble model drugs. Then, the monolayer osmotic pump tablets of ribavirin and the bilayer osmotic pump tablets of glipizide were prepared using SMS as the osmotically active substance and propellant. SMS was mainly composed of rhamnose, arabinose, xylose and galactose and exhibited relatively high swelling ability. The area of the disintegrated matrix tablet was 20.1 times as that at initial after swelling for 600 s. SMS swelled rapidly and was fully swelled (0.5%) in aqueous solution with relative low viscosity (3.66 +/- 0.03) mPa x s at 25 degrees C. The monolayer osmotic pump tablets of ribavirin and the bilayer osmotic pump tablets of glipizide using SMS as propellant exhibited typical drug release features of osmotic pumps. In conclusion, the swelling matrix derived from boat-fruited sterculia seed, with low viscosity and high swelling, is a potential propellant in the application of osmotic pump tablets.
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purpose To investigate the release properties of gatifloxacin in situ pH-sensitive gel in vitro.Methods The improved paddle method and the membraneless model were applied in assessing the drug release behavior.Results The gel erosion and drug release were increased with the increase of surface area and shaking frequency.The cumulative quantities of gel erosion were well correlated with the cumulative release of drug loaded in the gel.Conclusion Gatifloxacin was released from in situ pH-sensitive gel with zero-order kinetics characters,and drug release was mainly controlled by gel erosion.
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OBJECTIVE: To study the preparation technique of tanshinone dispersible tablets.METHODS: Taking the disintegration time - limit, in vitro dissolubility and suspensibility as indices, the formula of tanshinone dispersible tablets was screened by orthogonal design.RESULTS The dispersible tablets could completely disintegrate within 30 seconds and pass through 710m seive mesh, which all conformed to the requiremtes of BP(1993) .The in vitro dissolubility of this product was superior to that of ordinary tablets obviously .CONCLUSION: The preparation technique of tanshinone dispersible tablets is mature and the quality is reliable.