Hard-shell capsules commonly consist of gelatin which is not a universal material considering it is extracted from animal parts. Moreover, the mad cow disease triggered the scrutinization of the use of gelatin in pharmaceutical products. Hence, an alternative to conventional hard-shell capsules is needed. Carrageenan- (CRG-) based hard-shell capsules were successfully prepared by cross-linking CRG with maltodextrin (MD) and plasticizing with sorbitol (SOR). These CRG-MD/SOR hard-shell capsules were produced as an alternative to conventional hard-shell capsules in the oral drug delivery system (DDS). The physical properties of CRG-MD/SOR capsules were characterized using the degree of swelling, FTIR, and SEM analyses. The disintegration and dissolution profile release of paracetamol from CRG-MD/SOR hard-shell capsules was performed in an aqueous medium with three different pH levels. The degree of swelling of CRG-MD/SOR was 529.23±128.10%. The main peaks in the FTIR spectrum of CRG-MD/SOR were at 1248, 930, 847, and 805 cm−1 for ester sulfate groups, 3,6-anhydrogalactose, galactose-4-sulfate, and 3,6-anhydrogalactose-2-sulfate, respectively. The SEM analysis exhibited minuscule pores on the surface of CRG and CRG-MD/SOR at 5000 times of magnification. The CRG-MD/SOR capsules required 18.47±0.11 min on average to disintegrate. The CRG-MD/SOR dissolution was better in a weakly acidic medium (pH 4.5) than in a strongly acidic (pH 1.2) and neutral (pH 6.8) media. Based on the aforementioned results, CRG-MD/SOR capsules are the potential candidate to replace conventional hard-shell capsules.

Primaquine (PQ) has long been recognized as the only effective drug in the treatment of hepatic stage malaria. However, severe toxicity limits its therapeutical application. Combining PQ with chloroquine (CQ) has been reported as enhancing the former’s efficacy, while simultaneously reducing its toxicity. In this study, the optimal conditions for encapsulating PQ-CQ in liposome, including incubation time, temperature and drug to lipid ratio, were identified. Furthermore, the effect of the loading combination of these two drugs on liposomal characteristics and the drug released from liposome was evaluated. Liposome is composed of HSPC, cholesterol and DSPE-mPEG2000 at a molar ratio of 55:40:5 and the drugs were loaded by means of the transmembrane pH gradient method. The particle size, ζ-potential and drug encapsulation efficiency were subsequently evaluated. The results showed that all liposome was produced with a similar particle size and ζ -potential. PQ and CQ could be optimally loaded into liposome by incubating the mixtures at 60°C for 20 minutes at a respective drug to lipid ratio of 1:3 for PQ and CQ. However, compared to single drug loading, dual-loading of PQ+CQ into liposome resulted in lower drug encapsulation and slower drug release. In conclusion, PQ and CQ can be jointly loaded into liposome with differing profiles of encapsulation and drug release.

Background and purpose: Ursolic acid (UA) exhibits anti-hepatocarcinoma and hepatoprotective activities, thus promising as an effective oral cancer therapy. However, its poor solubility and permeability lead to low oral bioavailability. In this study, we evaluated the effect of different ratios of Span ® 60-cholesterol-UA and also chitosan addition on physical characteristics and stability of niosomes to improve oral biodistribution. Experimental approach: UA niosomes (Nio-UA) were composed of Span ® 60-cholesterol-UA at different molar ratios and prepared by using thin layer hydration method, and then chitosan solution was added into the Nio-UA to prepare Nio-CS-UA. Findings/Results: The results showed that increasing the UA amount increased the particle size of Nio-UA. However, the higher the UA amount added to niosomes, the lower the encapsulation efficiency. The highest physical stability was achieved by preparing niosomes at a molar ratio of 3:2:10 for Span ® 60, cholesterol, and UA, respectively, with a zeta-potential value of -41.99 mV. The addition of chitosan increased the particle size from 255 nm to 439 nm, as well as the zeta-potential value which increased from -46 mV to -21 mV. Moreover, Nio-UA-CS had relatively higher drug release in PBS pH 6.8 and 7.4 than Nio-UA. In the in vivo study, the addition of chitosan produced higher intensities of coumarin-6-labeled Nio-UA-CS in the liver than Nio-UA. Conclusion and implications: It can be concluded that the ratio of Span ® 60-cholesterol-UA highly affected niosomes physical properties. Moreover, the addition of chitosan improved the stability and drug release as well as oral biodistribution of Nio-UA.

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AbstractThe release of drugs from solid drug delivery materials has been studied intently in recent years. Quantitative analyses achieved from in vitro dissolution becomes easier if a zero-order mathematical model is used. Non-gelatin nutraceutical hard-shell capsules of zero size (approximately 0.7-0.8 cm) were produced from carrageenan-based natural polymers, namely carrageenan-alginate (CA) and carrageenan-starch (CS). Disintegration, dissolution and zero-order drug release kinetics of hard-shell capsules containing 100 mg of salicylamide were studied. The disintegration time of CA and CS were observed to be less than 30 min for both CA and CS. In vitro dissolution profile showed that the percentage dissolution of CA capsules was better at pH 4.5, while that of CS was poor at pH 1.2, 4.5 and 6.8. Determination of drug release kinetics profiles of carrageenan-based hardshell capsules utilized the Noyes-Whitney and Peppas-Sahlin modification rules for zero-order. The drug release from carrageenan-based capsules followed zero-order kinetics, especially at pH 6.8, and was compared to the Higuchi model. Salicylamide in CA hard-shell capsules at a pH 6.8 had a release rate constant (kH) of 2.91 %(ppm/ ppm) min-1/2, while the release rate constant of CS was 0.36 %(ppm/ppm) min-1.