A. Khaled

Evaluation of carboxymethyl-β-cyclodextrin with acid function: Improvement of chemical stability, oral bioavailability and bitter taste of famotidine

The objective of the present study was to evaluate the potential influence of carboxymethyl-beta-cyclodextrin (CM-beta-CyD) on the aqueous solubility, chemical stability and oral bioavailability of famotidine (FMT) as well as on its bitter taste. We examined the effect of the CM-beta-CyD on the acidic degradation of FMT compared with that for sulfobutyl-ether-beta-cyclodextrin (SBE-beta-CyD). The potential use of CM-beta-CyD for orally disintegrating tablets (ODTs) was evaluated in vitro and in vivo. A taste perception study was also carried out. A strong stabilizing influence of CM-beta-CyD was observed against the acidic degradation, in sharp contrast to SBE-beta-CyD which induced a weird destabilizing effect on FMT. (13)C NMR was used to investigate the interaction mode between FMT and the 2 CyDs. In vivo study of ODTs indicated a significant increase in C(max), AUC and oral bioavailability in the case of FMT-CM-beta-CyD tablets, compared with plain drug tablets. However, no significant difference in T(max) and t(1/2) was observed. CM-beta-CyD complexation appears to be an acceptable strategy for enhancing the oral bioavailability of FMT owing to its dramatic effect on the aqueous solubility and chemical stability of the drug. In addition, it has a pronounced effect on masking the bitter taste of FMT.

Enhancement of the Aqueous Solubility and Masking the Bitter Taste of Famotidine Using Drug/SBE-β-CyD/Povidone K30 Complexation Approach

The objective of the present study was to evaluate the potential of ternary system (comprised of famotidine, beta-cyclodextrin (beta-CyD) or its derivatives and a hydrophilic polymer) as an approach for enhancing the aqueous solubility and masking the bitter taste of famotidine. The aqueous solubility of famotidine increased in the presence of beta-CyDs, particularly sulfobutyl ether beta-CyD (SBE-beta-CyD), and it was further enhanced by the combination of SBE-beta-CyD and polyvinyl pyrrolidone (Povidone) K30. The solid binary (drug-beta-CyDs) and ternary (drug-beta-CyDs-Povidone K30) systems were prepared by the kneading and freeze-drying methods. The dissolution rates of these solid systems were much faster than that of the drug alone. A taste perception study was carried out, initially using a taste sensory machine and subsequently on human volunteers to evaluate the taste masking ability of the ternary complexation. Our results indicated that the combination of SBE-beta-CyD and Povidone K30 is effective not only in the enhancement of the solubility and dissolution rate of famotidine, but also in masking of the bitter taste of the drug. This technique may be of value for the pharmaceutical industries, especially in preparation of rapidly disintegrating tablets dealing with bitter drugs to improve patient compliance and thus effective pharmacotherapy.

Formulation and corneal permeation of ketorolac tromethamine-loaded chitosan nanoparticles

Abstract The aim of this work was to formulate chitosan (CS)-based nanoparticles (NPs) loaded with ketorolac tromethamine (KT) intended for topical ocular delivery. NPs were prepared using ionic gelation method incorporating tri-polyphosphate (TPP) as cross-linker. Following the preparation, the composition of the system was optimized in terms of their particle size, zeta potential, entrapment efficiency (EE) and morphology, as well as performing structural characterization studies using Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). The data suggested that the size of the NPs was affected by CS/TPP ratio where the diameter of the NPs ranged from 108.0 ± 2.4 nm to 257.2 ± 18.6 nm. A correlation between drug EE and the corresponding drug concentration added to the formulation was observed, where the EE of the NPs increased with increasing drug concentration, for up to 10 mg/mL. FT-IR and DSC revealed that KT was dispersed within the NPs where the phosphate groups of TPP were associated with the ammonium groups of CS. The in vitro release profile of KT from CS NPs showed significant differences (p < 0.05) compared to KT solution. Furthermore, mucoadhesion studies revealed adhesive properties of the formulated NPs. The KT-loaded NPs were found to be stable when stored at different storage conditions for a period of 3 months. The ex vivo corneal permeation studies performed on excised porcine eye balls confirmed the ability of NPs in retaining the drug on the eye surface for a relatively longer time. These results demonstrate the potential of CS-based NPs for the ocular delivery of KT.

Clinical efficacy of novel unidirectional buccoadhesive vs. vaginoadhesive bromocriptine mesylate discs for treating pathologic hyperprolactinemia

OBJECTIVE To test the clinical effectiveness of new bioadhesive unidirectional buccal and vaginal bromocriptine methylate discs in hyperprolactinemic patients. DESIGN A preliminary randomized comparative study. SETTING A pharmaceutical phase at the departments of Pharmaceutics, Faculties of Pharmacy, Assiut and El-Minea universities and a clinical phase at the Infertility Out-patient Clinic of Womens Health University Center, Assiut University, Assiut, Egypt. PATIENT(S) A total of 42 patients with pathologic hyperprolactinemia. INTERVENTION(S) Patients were randomly divided into two groups. Group A comprised 21 patients who used unidirectional buccoadhesive bromocriptine methylate discs once daily for 1 month. Group B included 21 patients who used vaginoadhesive bromocriptine methylate discs once daily for 1 month. Serum prolactin (PRL) was measured before and after therapy in all cases. MAIN OUTCOME MEASURE(S) Decline of serum PRL level after 1 month of therapy. RESULT(S) Pharmaceutically, tests for swelling, surface pH, in vitro and in vivo bioadhesion and in vitro release expressed satisfactory results. The in vitro release of vaginal bromocriptine from the discs is increased in pH 4.5 media. Both groups showed a highly statistically significant reduction of serum PRL levels after 1 month of therapy without any significant difference between both groups. The decline of serum PRL was not correlated with age, parity, or indication of entering into this study. CONCLUSION(S) Both buccoadhesive and vaginoadhesive discs containing bromocriptine are of equal efficacy for treating pathologic hyperprolactinemia. Buccoadhesive discs have the advantages of being gender nonspecific (i.e., could be used by men), avoiding manipulating the vagina, which could be inconvenient to some patients, such as virgins; not being dependent on cyclic estrogen (E) levels; and could be easily used during menstruation.

Poloxamer-based thermoresponsive ketorolac tromethamine in situ gel preparations: Design, characterisation, toxicity and transcorneal permeation studies

&NA; This study was aimed at preparing, characterising and evaluating in situ gel formulations based on a blend of two hydrophilic polymers i.e. poloxamer 407 (P407) and poloxamer 188 (P188) for a sustained ocular delivery of ketorolac tromethamine (KT). Drug‐polymer interaction studies were performed using DSC and FT‐IR. The gelation temperature (Tsol‐gel), gelation time, rheological behaviour, mucoadhesive characteristics of these gels, transcorneal permeation and ocular irritation as well as toxicity was investigated. DSC and FT‐IR studies revealed that there may be electrostatic interactions between the drug and the polymers used. P188 modified the Tsol/gel of P407 bringing it close to eye temperature (35 °C) compared with the formulation containing P407 alone. Moreover, gels that comprised P407 and P188 exhibited a pseudoplastic behaviour at different concentrations. Furthermore, mucoadhesion study using mucin discs showed that in situ gel formulations have good mucoadhesive characteristics upon increasing the concentration of P407. When comparing formulations PP11 and PP12, the work of adhesion decreased significantly (P < 0.001) from 377.9 ± 7.79 mN mm to 272.3 ± 6.11 mN mm. In vitro release and ex vivo permeation experiments indicated that the in situ gels were able to prolong and control KT release as only 48% of the KT released within 12 h. In addition, the HET‐CAM and BCOP tests confirmed the non‐irritancy of KT loaded in situ gels, and HET‐CAM test demonstrated the ability of ocular protection against strongly irritant substances. MTT assay on primary corneal epithelial cells revealed that in situ gel formulations loaded with KT showed reasonable and acceptable percent cell viability compared with control samples. Graphical abstract In this study, the thermoresponsive behaviour of poloxamers was employed as a trigger for the formation of in situ gel systems incorporating ketorolac tromethamine (KT) (A). The protective effect of KT loaded in situ gel preparation on 10 day old chorioallantoic membrane (CAM) has been investigated after treating the CAM with a strong irritant, NaOH (B). The BCOP test revealed the corneal opacity and permeability of the prepared in situ gel system (C). The MTT cytotoxicity assay demonstrated that the cell viability when treated with the selected in situ gel preparations was at an acceptable level compared to the control samples (D). Figure. No caption available.

Preparation and evaluation of polyamidoamine dendrimer conjugate with glucuronylglucosyl-β-cyclodextrin (G3) as a novel carrier for siRNA.

Abstract In this study, we newly synthesized the polyamidoamine STARBURST dendrimer (dendrimer, generation 3: G3) conjugates with 6-O-α-(4-O-α-d-glucuronyl)-d-glucosyl-β-cyclodextrin [GUG-β-CDE (G3)] having the various degrees of substitution (DS) of GUG-β-cyclodextrin of 1.6, 3.0, 3.7, 5.0 and 8.6, and evaluated them as a siRNA transfer carrier. GUG-β-CDEs (G3) formed the positively charged and nano-order complexes with siRNA. Of the siRNA complexes with five GUG-β-CDEs (G3), the complex with GUG-β-CDE (G3, DS 3.7) showed the highest RNAi effect and cellular uptake with negligible cytotoxicity in KB cells at a charge ratio of 20. In addition, the RNAi effect and cellular uptake of the complex with GUG-β-CDE (G3, DS 3.7) were higher than those of α-CDE (G3, DS 2.4) and comparable to those of Lipofectamine™ 2000. Furthermore, the complex with GUG-β-CDE (G3, DS 3.7) possessed the endosomal escaping ability, the releasing property of siRNA in the cytoplasm and serum resistance. These results suggest that GUG-β-CDE (G3, DS 3.7) has the potential as a novel siRNA carrier.

Evaluation of combined famotidine with quercetin for the treatment of peptic ulcer: in vivo animal study.

The aim of this work was to prepare a combined drug dosage form of famotidine (FAM) and quercetin (QRT) to augment treatment of gastric ulcer. FAM was prepared as freeze-dried floating alginate beads using ion gelation method and then coated with Eudragit RL100 to sustain FAM release. QRT was prepared as solid dispersion with polyvinyl pyrrolidone K30 to improve its solubility. Photo images and scanning electron microscope images of the prepared beads were carried out to detect floating behavior and to reveal surface and core shape of the prepared beads. Anti-ulcerogenic effect and histopathological examination of gastric tissues were carried out to investigate the effect of the combined drug formulation compared with commercial FAM tablets and FAM beads. Gastric glutathione (GSH), superoxide dismutase, catalase, tissue myeloperoxidase, and lipid peroxidation enzyme activities and levels in rat stomach tissues were also determined. Results revealed that spherical beads were formed with an average diameter of 1.64±0.33 mm. They floated immediately with no lag time before floating, and remained buoyant throughout the test period. Treatment with a combination of FAM beads plus QRT showed the absence of any signs of inflammation or hemorrhage, and significantly prevented the indomethacin-induced decrease in GSH levels (P<0.05) with regain of normal GSH gastric tissue levels. Also, there was a significant difference in the decrease of malondialdehyde level compared to FAM commercial tablets or beads alone (P<0.05). The combined formula significantly improved the myeloperoxidase level compared to both the disease control group and commercial FAM tablet-treated group (P<0.05). Formulation of FAM as floating beads in combination with solid dispersion of QRT improved the anti-ulcer activity compared to commercially available tablets, which reveals a promising application for treatment of peptic ulcer.

Improved corneal bioavailability of ofloxacin: biodegradable microsphere-loaded ion-activated in situ gel delivery system

The aim of the study was to improve corneal penetration and bioavailability of ofloxacin (OFX) eye preparations. OFX was incorporated in poly (lactide-co-glycolide) as biodegradable microspheres using oil in oil emulsion solvent evaporation technique. The prepared OFX microspheres were then incorporated in Gelrite® in situ gel preparation. In addition, OFX Gelrite-based in situ gel formulations were prepared. OFX formulations were characterized for gelling capacity, viscosity, and rheological properties. Release studies for OFX microspheres, OFX in situ gel, and OFX-loaded microspheres in situ gel formulations were carried out to investigate release characteristics of the drug. The prepared OFX formulations were then investigated in vivo compared with commercially available OFX eyedrops. Results showed that the optimum Gelrite concentration was at 0.4%–0.7% w/v; the prepared formulations were viscous liquid transformed into a pourable gel immediately after the addition of simulated tear fluid with a gelling factor of 27–35. Incorporation of OFX-loaded microspheres in Gelrite solution (0.4% w/v) significantly altered the release profiles of OFX-loaded microspheres in situ gel formula compared with the corresponding OFX gels and OFX microspheres. In vivo results in rabbits showed that OFX-loaded microspheres in situ gel formula improved the relative bioavailability by 11.7-fold compared with the commercially available OFX eyedrops. In addition, the longer duration of action of OFX-loaded microspheres in situ gel formula preparations is thought to avoid frequent instillations, which improves patient tolerability and compliance.

Targeted siRNA delivery to tumor cells by folate-PEG-appended dendrimer/glucuronylglucosyl-β-cyclodextrin conjugate

We previously reported the utility of 6-O-α-(4-O-α-d-glucuronyl)-d-glucosyl-β-cyclodextrin (GUG-β-CyD) conjugates with polyamidoamine dendrimer [GUG-β-CDE (generation 3; G3)] as siRNA carriers. In this study, to prepare GUG-β-CDE (G3) possessing a targeting ability to tumor cells overexpressing folate receptor-α (FR-α), we newly synthesized folate-polyethylene glycol (PEG)-appended GUG-β-CDEs (G3) [Fol-PEG-GUG-β-CDEs (G3)] having degrees of substitution of folate (DSF) of 3.9, 6.7 and 7.3, and evaluated their utility as tumor-selective siRNA carriers. Of various Fol-PEG-GUG-β-CDEs (G3), Fol-PEG-GUG-β-CDE (G3, DSF6.7) showed the highest siRNA transfection activity at a charge ratio of 50 (carrier/siRNA) in both 786-0-luc cells [FR-α (+)] and KB cells [FR-α (+)]. In addition, the cellular uptake of the complex was significantly decreased by an addition of folic acid in a concentration-dependent manner, suggesting its FR-α-mediated endocytosis pathway. Moreover, Fol-PEG-GUG-β-CDE (G3, DSF6.7)/siRNA complex induced a potent RNAi effect, comparable to Lipofectamine™ 2000/siRNA complex. Furthermore, Fol-PEG-GUG-β-CDE (G3, DSF6.7) complex with siRNA against Polo-like kinase 1 (siPLK1) showed a significant cytotoxic activity in KB cells. Thus, Fol-PEG-GUG-β-CDE (G3, DSF6.7) has the potential as the targeted siRNA delivery carrier for FR-α-overexpressing tumor cells.

Co-administration of liposomal l-OHP and PEGylated TS shRNA-lipoplex: A novel approach to enhance anti-tumor efficacy and reduce the immunogenic response to RNAi molecules

&NA; Many therapeutic strategies have been applied in efforts to conquer the development and/or progression of cancer. The combination of chemotherapy and an RNAi‐based approach has proven to be an efficient anticancer therapy. However, the feasibility of such a therapeutic strategy has been substantially restricted either by the failure to achieve the efficient delivery of RNAi molecules to tumor tissue or by the immunostimulatory response triggered by RNAi molecules. In this study, therefore, we intended to investigate the efficacy of using liposomal oxaliplatin (liposomal l‐OHP) to guarantee the efficient delivery of RNAi molecules, namely shRNA against thymidylate synthase (TS shRNA) complexed with cationic liposome (TS shRNA‐lipoplex), to solid tumors, and to suppress the immunostimulatory effect of RNAi molecules, TS shRNA, following intravenous administration. Herein, we describe how liposomal l‐OHP enhanced the intra‐tumor accumulation of TS shRNA‐lipoplex and significantly reduced the immunostimulatory response triggered by TS shRNA. Consequently, such enhanced accumulation of TS shRNA‐lipoplex along with the cytotoxic effect of liposomal l‐OHP led to a remarkable tumor growth suppression (compared to mono‐therapy) following systemic administration. Our results, therefore, may have important implications for the provision of a safer and more applicable combination therapy of RNAi molecules and anti‐cancer agents that can produce a more reliable anti‐tumor effect. Graphical abstract Figure. No caption available.