Current Drug Delivery - Volume 10, Issue 6, 2013

The purpose of present research work was to design and optimize compression coated tablet to provide an immediate release of hydrochlorothiazide in stomach and extended release of metoprolol succinate in intestine. Compression coated tablet was prepared by direct compression method which consisted of metoprolol succinate extended release core tablet and hydrochlorothiazide immediate release coat layer. Barrier coating of Hydroxy Propyl Methyl Cellulose (HPMC) E15LV was applied onto the core tablets to prevent burst release of metoprolol succinate in acidic medium. A 32 full factorial design was employed for optimization of the amount of polymers required to achieve extended release of drug. The percentage drug release at given time Q3, Q6, Q10, Q22; were selected as dependent variables. Core and compression coated tablets were evaluated for pharmaco-technical parameters. In vitro drug release of optimized batch was found to comply with Pharmacopoeial specifications. Desired release of metoprolol succinate was obtained by suitable combination of HPMC having high gelling capacity and polyethylene oxide having quick gelling capacity. The mechanism of release of metoprolol succinate from all batches was anomalous diffusion. Optimised batch was stable at accelerated conditions up to 3 months. Thus, compression coated tablet of metoprolol succinate and hydrochlorothiazide was successfully formulated.

The dissolution of piroxicam is a limiting step in its bioavailability on account of its hydrophobicity. The objective of this research was to formulate novel solid lipid microparticles (SLMs) based on homolipids (admixtures of tallow fat (TF) and Softisan® 142 (SFT) templated with Phospholipon® 90G (P90G), a heterolipid for the delivery of piroxicam. Lipid matrices consisting of TF and SFT in ratios of 1:1, 1:2 and 2:1 were templated with the heterolipid, P90G and characterized by differential scanning calorimetry (DSC). The SLMs produced by hot homogenization technique using the matrices were characterized in terms of thermal properties, particle size, morphology, drug encapsulation efficiency, stability studies and in vitro diffusion studies. In vivo pharmacodynamic study was performed using egg albumin- induced pedal edema in rats. The results showed that addition of Softisan® 142 improved the drug holding capacity of the micellar solution of 2:1 mixture of TF and SFT. The in vitro diffusion of piroxicam from this SLM showed maximum release of 87.53 % and followed non-Fickian diffusion kinetic mechanism. At dose equivalence of 10 mg, piroxicamloaded SLMs showed superior in vivo anti-inflammatory properties at 3 h than Feldene® and the pure drug sample. This study has shown that surface-modified SLMs could confer favourable properties with respect to drug release and antiinflammatory activity on SLMs for the delivery of piroxicam, thus encouraging further development of the formulations.

Solid lipid nanoparticles (SLN) are very potential formulations for topical delivery of anti-inflammatory and anti-arthritic drugs. The solid state of the lipid particles enable efficient drug encapsulation and controlled drug release. In the present study, the evaluation of different formulation parameters based on variation of concentration of lipid and cosurfactant was studied. The SLN gel formulations of the dispersions were compared to the SLN dispersions and with the marketed gel of aceclofenac. The SLNs were prepared by high speed homogenization and ultra-sonication method with fixed amount of aceclofenac (10%) and pluronic F68 (1.5%). The particle size, zeta potential and span of developed formulations was found to be within the range of 123 nm to 323 nm, -12.4 to -18.5 and 0.42 to 0.86 respectively as the lipid concentration was increased from 7.5% to 40%. The highest entrapment efficiency was found to be 75% with the formulation having lipid concentration of 30% and 0.85% of phospholipon 90G. Permeation rate and controlled release property of xanthan gum loaded SLN gel formulations and SLN dispersion was studied through excised pig skin for 24hr. The drug release of SLN gel formulations was better controlled as compare to SLN dispersions. In vivo anti-inflammatory study showed that action of aceclofenac was enhanced for SLN dispersion and gel formulations. The results indicated the superiority of SLN based formulations for topical delivery of aceclofenac.

Many pharmaceutical companies are switching their products from tablets to fast dissolving oral thin films (OTFs). Films have all the advantages of tablets (precise dosage, easy administration) and those of liquid dosage forms (easy swallowing, rapid bioavailability). Statistics have shown that four out of five patients prefer orally disintegrating dosage forms over conventional solid oral dosages forms. Pediatric, geriatric, bedridden, emetic patients and those with Central Nervous System disorders, have difficulty in swallowing or chewing solid dosage forms. Many of these patients are non-compliant in administering solid dosage forms due to fear of choking. OTFs when placed on the tip or the floor of the tongue are instantly wet by saliva. As a result, OTFs rapidly hydrate and then disintegrate and/or dissolve to release the medication for local and/or systemic absorption. This technology provides a good platform for patent non- infringing product development and for increasing the patent life-cycle of the existing products. The application of fast dissolving oral thin films is not only limited to buccal fast dissolving system, but also expands to other applications like gastroretentive, sublingual delivery systems. This review highlights the composition including the details of various types of polymers both natural and synthetic, the different types of manufacturing techniques, packaging materials and evaluation tests for the OTFs.

Interest in hepatocyte-directed liposomal gene delivery is driven, in part, by the lack of effective treatment for several liver-associated disorders. To impart a hepatocyte targeting capability on DNA-lipoplexes, and to promote early release of cargo DNA from endosomes, novel glycosylated and imidazolylated cholesteryl derivatives have been synthesized and evaluated in vitro. Thus cholesteryl-3β-N-[(lactobionyl) amino] carbamate (Chol-LAC) and cholesteryl-3β-N- [(urocanyl) amino] carbamate (Chol-UAC) have been formulated with the cytofectin cholesteryl-3β-[(N’,N’- dimethylaminopropyl) carbamate (Chol-T) and the neutral co-lipid dioleoylphosphatidyl ethanolamine (DOPE). Liposomes, which displayed a buffering capability at endosomal pH, effectively bound DNA at a N/P ratio of 0.8:1 and offered partial protection against serum nuclease digestion. The MTT cell viability assay showed that lipoplexes were well tolerated by human hepatoma cells (HepG2), which were efficiently transfected almost exclusively by asialoglycoprotein receptor (ASGP-R)–mediation, as demonstrated in competition assays. In the ASGP-R-negative human kidney cell line (HEK293) transfection levels were considerably lower (P < 0.001). Therefore the combination of Chol-LAC and Chol- UAC in cationic liposomal formulations may provide a platform for the development of useful hepatotropic gene delivery systems.

Ondansetron, selective serotonin (5-HT3) receptor blocker, is used in treating chemotherapy induced nausea and vomiting in cancer patients. Mouth dissolving films containing ondansetron were developed to have better onset and patient compliances. The drug content of prepared films was within 85%-115%. The films were found to be stable for 4 months when stored at 40 °C and 75% RH. In-vitro dissolution studies suggested a rapid disintegration, in which most of ondansetron was released (91.5±3.4%) within 90 sec. Subsequently, Sprague–Dawley rats were used to compare pharmacokinetic parameters of the formulated films with oral administration of pure drug solution. Pharmacokinetic parameters were similar between the two groups in which AUC0-t (ng h/ml), AUC0-∞ (ng h/ml), Cmax (ng/ml), Tmax (min), Kel (h-1) and t1/2 (h) of reference was 109.091±15.73, 130.32±18.56, 28.5±4.053, 60, 0.1860±0.0226, and 3.771±0.498 respectively; and for formulated film 113.663±16.64, 151.79±16.54, 30±3.51, 60, 0.1521±0.0310 and 4.755±0.653 respectively. These results suggest that the fast dissolving film containing ondansetron is likely to become one of the choices to treat chemotherapy induced nausea and vomiting.

The present investigation deals with the determination of bioavailability of Rofecoxib solid dispersion compared to pure rofecoxib (RFB). The study of a non-blinded, open-label, crossover design was conducted in six healthy volunteers. Blood samples were collected for 12 h at specified intervals of time after the administration of formulations and analysed by suitable HPLC method. The pharmacokinetic parameters such as maximum plasma concentration (Cmax), time to reach (tmax), elimination rate constant (Kel) biological half-life (t1/2), absorption rate constant (Ka) and area under curve (AUC0-12 and AUC0-) were determined. Significant difference in the bioavailability of pure rofecoxib and solid mixture of rofecoxib prepared using hupu gum as carrier has been reported from the studies. The Peak plasma concentrations (Cmax) of 8.34 ng/mL at tmax of 4 h and Cmax of 76.84 ng/mL at tmax of 3 h were observed for RFB and solid mixture respectively. The results clearly indicated an enhancement in the bioavailability of rofecoxib in solid mixture preparation.

Adherence to treatment is a major determinant of outcome in bipolar disorder. Poor insight, attitudes towards treatment, and poor understanding of medications and the illness can all lead to reduced adherence. Nonadherence and partial adherence both also appear to play a significant role in relapse and recurrence. Clinicians can address the problem of poor adherence by ensuring medication administration. Assured administration can be accomplished with long-acting atypical antipsychotic medications. Case series and naturalistic trials utilizing first generation antipsychotics suggest that depot antipsychotics are effective in reducing relapse in bipolar illness. Controlled studies with second generation agents confirm this impression. Depot antipsychotics, including long-acting first- and second-generation agents, can be important adjuncts in the long-term management of bipolar illness.

The average molecular mass of β-glucan was 241,700 g/mol with a polydispersity of 1.433. At lower concentrations, gels showed Newtonian flow behaviour and shear thinning properties at higher concentrations. There was no effect of pH on the flow properties of the β-glucans at lower concentrations of 1% while at higher concentrations of 4% and above viscosity increased with pH 4 or greater. A progressive decrease in viscosity with increasing temperature for all concentrations of samples tested at a constant shear rate was observed. A set gel structure was not formed below 3% β-glucan so 2% solutions were used to incorporate lactoferrin at room temperature prior to film casting and cryomilling to prepare microparticles. There was an initial burst lactoferrin release from all microparticles, with final amount released after 7 hours only 35 and 32 % for β-glucan alone or with the addition of PEG 2000 respectively. Final lactoferrin release after 7 hours was 91% when Kolicoat was added to the formulation. Stress studies on β-glucan indicated that there was no degradation of the β-glucan at gastric conditions of low pH, which suggests that β-glucan might protect fragile molecules under gastric conditions.

Poly (lactic-co-glycolic acid) (PLGA (92:8)) and a series of PLGA-PEG-PLGA tri block copolymers were synthesized by direct melt polycondensation. The copolymers were characterized by FTIR, and 1HNMR spectroscopic techniques, viscosity, gel permeation chromatography (GPC) and powder x-ray diffraction (XRD). The rifampicin (RIF) loaded polymeric nanospheres (NPs) were prepared by ultrasonication-W/O emulsification technique. The NPs have been characterized by field emission scanning electron microscopy (FESEM), TEM, powder X-ray diffraction (XRD), UVvisible spectroscopy and DLS measurements. The drug loaded triblock copolymeric NPs have five folds higher drug content and drug loading efficiency than that of PLGA microspheres (MPs). The in vitro drug release study shows that the drug loaded NPs showed an initial burst release after that sustained release up to 72 h. All the triblock copolymeric NPs follow anomalous drug diffusion mechanism while the PLGA MPs follow non-Fickian super case-II mechanism up to 12 h. The overall in-vitro release follows second order polynomial kinetics up to 72 h. The antimicrobial activity of the RIF loaded polymer NPs was compared with that of pure RIF and tetracycline (TA). The RIF loaded triblock copolymeric NPs inhibited the bacterial growth more effectively than the pure RIF and TA.

Although release profiles of drug from hydrophilic matrices have been well recognized, the visual distribution of hydroxypropylmethylcellulose (HPMC) and atoms inside of internal structures of hydrophilic HPMC matrices has not been characterized. In this paper, drug release mechanism from HPMC matrix tablet was investigated based on the release behaviors of HPMC, physical properties of gelled HPMC tablet and atomic distributions of formulation components using diverse instruments. A matrix tablet consisting of hydroxypropyl methylcellulose (HPMC 6, 4,000 and 100,000 mPa·s), chlorpheniramine maleate (CPM) as a model and fumed silicon dioxide (Aerosil® 200) was prepared via direct compression. The distribution of atoms and HPMC imaging were characterized using scanning electron microscope (SEM)/ energy-dispersive X-ray spectroscopy (EDX), and near-infrared (NIR) analysis, respectively as a function of time. A texture analyzer was also used to characterize the thickness and maintenance of gel layer of HPMC matrix tablet. The HPMC matrix tablets showed Higuchi release kinetics with no lag time against the square root of time. High viscosity grades of HPMC gave retarded release rate because of the greater swelling and gel thickness as characterized by texture analyzer. According to the NIR imaging, low-viscosity-grade HPMC (6 mPa·s) quickly leached out onto the surface of the tablet, while the high-viscosity-grade HPMC (4000 mPa·s) formed much thicker gel layer around the tablet and maintained longer via slow erosion, resulting in retarded drug release. The atomic distribution of the drug (chlorine, carbon, oxygen), HPMC (carbon, oxygen) and silicon dioxide (silica, oxygen) and NIR imaging of HPMC corresponded with the dissolution behaviors of drug as a function of time. The use of imaging and texture analyses could be applicable to explain the release- modulating mechanism of hydrophilic HPMC matrix tablets.

The objective of this study was to optimize the particle size and encapsulation efficiency of chitosan nanoparticles loaded with 5-Fluorouracil (5-FU) by response surface methodology. Nanoparticles were prepared by ionic gelation method from chitosan and penta sodium triphosphate (TPP) at different combinations of chitosan viscosity, chitosan concentration and chitosan/TPP mass ratio according to the Box-Behnken experimental design. The particle size and encapsulation efficiency of prepared particles were measured by dynamic light scattering and UV spectroscopy, respectively, and the obtained data were subjected to multiple linear regression analysis followed by multi-attribute utility analysis to obtain a model for prediction of the optimum response. The optimum conditions for the production of 5-FU loaded chitosan nanoparticles were found to be low viscosity chitosan 0.5-1 mg/mL, middle viscosity chitosan 0.5-0.8 mg/mL and high viscosity chitosan 0.5-0.75 mg/mL and chitosan/TPP mass ratio of 4 or 6, yielding nanoparticles at the average diameter range of 114-188 nm and encapsulation efficiencies between 42-55%.

In recent years, Poloxamers had attracted a particular interest in the design of dermal and transdermal delivery systems in order to improve or retard drug permeation through the skin. In the present study, the influence of different parameters, such as, temperature, storage time, type of polymer (Lutrol® F-127 and Lutrol® F-108) and the addition of two types of drugs (ibuprofen and hydrocortisone) in the pH, texture and rheological behavior of topical pharmaceutical formulations containing poloxamers was assessed. In fact, the type of polymer used in the preparation of the hydrogels, the type of drug incorporated, the temperature and the storage time caused changes in the pH, texture and rheological behavior of topical formulations containing Lutrol® F-127 and Lutrol® F-108. Lutrol® F-127 hydrogels showed higher values of pH, firmness, adhesiveness and viscosity than Lutrol® F-108 hydrogels. The chemical nature of the drugs incorporated in these poloxamer hydrogels influence the pH of the preparations. Low percentages of drug incorporated into both types of hydrogels didn’t affect significantly their textural and rheological characteristics. The hydrogels prepared with Lutrol® F- 127 proved to be more resistant to temperature variations, maintaining their rheological behavior over time.

The objective of this study was to develop and evaluate mucoadhesive microsphere of diclofenac sodium with natural gums for sustained delivery. Guar gum and tragacanth were used along with sodium alginate as mucoadhesive polymers. Microspheres were formulated using orifice-ionic gelation method. Particle size, surface morphology, swelling study and drug entrapment efficiency of the prepared microspheres were determined. In vitro evaluation was carried out comprising of mucoadhesion and drug release study. The prepared microspheres were discrete and free flowing. Sodium alginate and natural gum, at a ratio of 1:0.25, showed good mucoadhesive property and they had high drug entrapment efficiencies. They also exhibited the best rate retarding effect among all the formulations. Drug entrapment efficiency of all the microspheres ranged from 80.42% to 91.67%. An inverse relationship was found between extent of crosslinking and drug release rate. Release rate was slow and extended in case of the formulations of 1:0.25 ratio (F1 and F3), releasing 68.36% and 70.56% drug respectively after 8 hours. Tragacanth-containing microspheres of F1 showed superiority over other formulations, with best mucoadhesive and rate retarding profile. The correlation value (r2) indicated that the drug release of all the formulations followed Higuchi’s model. Overall, the results indicated that mucoadhesive microspheres containing natural gum can be promising in terms of prolonged delivery with good mucoadhesive action, targeting the absorption site to thrive oral drug delivery.