Zeta potential changing self-nanoemulsifying drug delivery systems: A newfangled approach for enhancing oral bioavailability of poorly soluble drugs.

The mucus is a defensive barrier for different drug-loaded systems. To overcome this obstacle, the crucial factor is the surface charge. Due to mucus negative charge behavior; it was revealed that negatively charged formulations can move across mucus, whereas positively charged nanoformulations could not diffuse via mucus due to interactions. However, cellular intake of negatively charged nanoformulations to the epithelium by endocytosis is less prominent as compared to positively charged carriers. Self-emulsifying drug delivery systems (SEDDS) improve the drug permeability of drugs, especially which have poor oral drug solubility. Moreover, SEDDS have the ability to reduce the degradation of drugs in the GI tract. Currently, drug carrier systems that can shift zeta potential from negative to positive were developed. The benefits of inducing zeta potential changing approach are that negatively charged nanoformulations permeate quickly across the mucus and surface charges reversed to positive at epithelium surface to increase cellular uptake. Among various systems of drug delivery, zeta potential changing SEDDS seem to signify a promising approach as they can promptly diffuse over mucus due to their smaller size and shape distortion ability. Due to such findings, mucus permeation and drug diffusion may improve by the mixture of the zeta potential changing approach and SEDDS.

Ethyl-acetate extract of tara mira (Eruca sativa) alleviates the inflammation and rheumatoid arthritis in rats.

Eruca sativa, member of family Brassicaceae, was evaluated for its anti-arthritic potential. Both in vitro and in vivo models were used to bring out a safe, effective and economical remedy. In vitro tests included egg albumin denaturation suppression, bovine serum albumin assay and human red blood cells maintenance assay. While in vivo formaldehyde-induced arthritic model was initiated to check effect on paw volume. Similarly, carrageenan produced inflammation was applied to check anti-inflammatory ability of the plant. Acute toxicity studies showed safety margin at 2000mg/kg. The plant showed concentration dependent denaturation protection and membrane stability in vitro assays. Likewise, the carrageenan and formaldehyde investigations revealed visible paw volume reduction in dose attributed manner, with maximum outcome at dose of 500mg/kg. Hence, it may be established on the ground of presented results that ethyl-acetate extract of Eruca sativa has significant anti-inflammatory and anti-arthritic effects and may be considered for further research to reveal the core mechanism.

S-Protected thiolated nanostructured lipid carriers exhibiting improved mucoadhesive properties.

The purpose of the present study was to design nanostructured lipid carriers (NLCs) exhibiting improved mucoadhesive properties. First, an S-protected thiolated fatty acid conjugate was synthesized by amide bond formation between a primary amino group of l-cystine and palmitic acid N-hydroxysuccinimide. NLCs were prepared by nano-template engineering technique using Span 60, polysorbate 80, sucrose stearate and PEG 400 as surfactant mixture, stearic acid as solid lipid and miglyol as liquid lipid. NLCs were loaded with the model drug bergapten and decorated with the S-protected thiolated fatty acid conjugate. NLCs were characterized regarding particle size, poly-dispersity index (PDI), zeta potential, drug entrapment efficiency (EE), drug loading capacity (LC), drug release and mucoadhesive properties. Furthermore, cytotoxicity studies were performed on MDA-MB-231 cells via resazurin assay. S-Protected thiolated NLCs displayed a mean size of 115 nm, PDI of 0.3, zeta potential of -30 mV, 80% drug EE and 5% drug LC. Drug-loaded S-protected thiolated NLCs exhibited a sustained drug release and strongly enhanced mucoadhesive properties. Surface decoration with cystine substructures raised the cytotoxic potential of NLCs to a minor extent. Due to the immobilization of cystine substructures on the surface of NLCs, their mucoadhesive properties can be strongly improved.

Tetradeca-thiolated cyclodextrins: Highly mucoadhesive and in-situ gelling oligomers with prolonged mucosal adhesion.

The purpose of this study was to synthesize a highly mucoadhesive tetradeca-thiolated ß-cyclodextrin (ß-CD) by replacement of all primary OH groups at C-6 position and all secondary OH groups at C-2 position of ß-CD backbone viaSH groups and to evaluate its rheological and mucoadhesive properties in-vitro. Primary and secondary OH groups of ß-CD were substituted by SH groups using a microwave-assisted method. The structure of tetradeca-thiolated ß-CD was confirmed by FTIR and 1H NMR spectroscopy. The modified ß-CD was evaluated for SH content, thiol stability towards oxidation and cytotoxicity. Moreover, the viscoelastic behavior of the modified oligomer was investigated via rheological studies with porcine intestinal mucus and fibrous structural protein keratin, whereas mucoadhesive properties were evaluated using different porcine mucosae. Tetradeca-thiolated ß-CD oligomer displayed 8144 ± 317 µmol thiol groups per gram. These thiol groups displaying a pKa value of 8.2 were stable at pH 4 but prone to oxidation at higher pH values. The newly synthesized thiolated CD did not show any cytotoxicity to Caco-2 cells at a concentration of 0.5% (m/v) within 24 h. Due to the addition of 0.5 and 2% (m/v) tetradeca-thiolated ß-CD to mucus and keratin, the dynamic viscosity was increased up to 7.6- and 5.9- fold, respectively, within 4 h at 37 °C. Moreover, in-vitro mucoadhesion studies of tetradeca-thiolated CD showed 78.6-, 60.3-, 62.3- and 49.3- fold improved mucoadhesion on intestinal, buccal, bladder and vaginal mucosa as compared to unmodified ß-CD, respectively. According to these results, tetradeca-thiolated ß-CD might be a promising auxiliary agent to provide a prolonged residence time of drug delivery systems on different mucosal surfaces.

Development of pre-activated α-cyclodextrin as a mucoadhesive excipient for intra-vesical drug delivery.

The study was designed to synthesize and characterize pre-activated α-cyclodextrin (α-CD) derivatives as mucus adhering excipients for intra-vesical drug delivery. Sodium periodate (NaIO4) was used to oxidize α-CD and subsequently cysteamine was covalently attached to carbonyl groups of oxidized α-CD via reductive amination to produce thiolated α-CD. l-cysteine-2-mercaptonicotinic acid conjugate (Cys-MNA) was covalently attached to carbonyl groups of oxidized α-CD to produce pre-activated α-CD having enhance stability against oxidation at higher pH. Thiolated and pre-activated α-CD derivatives were quantitatively assayed for the attached thiol groups and MNA groups, respectively. Cell viability and tolerability was evaluated via resazurin assay and via red blood cells (RBC) lysis assay, respectively. Mucoadhesive properties were evaluated on porcine bladder mucosa. Trimethoprim (TMP) was encapsulated into thiolated and pre-activated α-CD derivatives and the dissolution behavior was evaluated in vitro. Thiol groups attached to thiolated α-CD derivatives α-CD-SH780 and α-CD-SH1426 were 780±68µmol/g and 1426±66µmol/g, respectively. For the entirely pre-activated α-CD derivatives, α-CD-MNA3609 and α-CD-MNA4285 number of attached MNA groups were 3609±19µmol/g and 4285±43µmol/g, respectively. Thiolated and pre-activated derivatives of α-CD did not show adverse effects to cells determined via resazurin and RBC lysis assays. Mucoadhesion on porcine bladder mucosa was significantly improved for thiolated and pre-activated α-CD derivatives. Thiolated α-CD-SH1426 showed 15-fold and pre-activated α-CD-MNA4285 showed 25-fold improved mucoadhesion compared to unmodified α-CD. Further, pre-activated α-CD-MNA4285 showed 2-fold enhanced dissolution of encapsulated TMP compared to free TMP over 3 h. The study shows that pre-activated α-CD could be an excipient of the choice for the formulations of mucoadhesive intra-vesical drug delivery systems.