A novel asymmetric membrane osmotic pump capsule with in situ formed delivery orifices for controlled release of gliclazide solid dispersion system

A pH-Responsive Asymmetric Microfluidic/Chitosan Device for Drug Release in Infective Bone Defect Treatment

Bacterial infection is currently considered to be one of the major reasons that leads to the failure of guided bone regeneration (GBR) therapy. Under the normal condition, the pH is neutral, while the microenvironment will become acid at the sites of infection. Here, we present an asymmetric microfluidic/chitosan device that can achieve pH-responsive drug release to treat bacterial infection and promote osteoblast proliferation at the same time. On-demand release of minocycline relies on a pH-sensitive hydrogel actuator, which swells significantly when exposed to the acid pH of an infected region. The PDMAEMA hydrogel had pronounced pH-sensitive properties, and a large volume transition occurred at pH 5 and 6. Over 12 h, the device enabled minocycline solution flowrates of 0.51-1.63 µg/h and 0.44-1.13 µg/h at pH 5 and 6, respectively. The asymmetric microfluidic/chitosan device exhibited excellent capabilities for inhibiting Staphylococcus aureus and Streptococcus mutans growth within 24 h. It had no negative effect on proliferation and morphology of L929 fibroblasts and MC3T3-E1 osteoblasts, which indicates good cytocompatibility. Therefore, such a pH-responsive drug release asymmetric microfluidic/chitosan device could be a promising therapeutic approach in the treatment of infective bone defects.

Solid dispersion technology as a formulation strategy for the fabrication of modified release dosage forms: A comprehensive review

Solubility limited bioavailability is one of the crucial parameters that affect the formulation development of the new chemical entities. Thus the major constraint in the pharmaceutical product development is the suitable solubility enhancement technique for Active Pharmaceutical Ingredient. Solid dispersion (SD) is an established and preferred method for improving the solubility which ultimately may be helpful to enhance bioavailability. For long period of time Amorphous solid dispersion (ASD) have been preferred for improving solubility, but since last two decades, ASD approach have been combined with different modified release approaches to improvise the stability and site specificity of SD to grasp a hold over the specific advantages associated with such dosage forms. It is an established fact now that the SD technique not only improves solubility limited bioavailability, but it may be combined with other approaches to modify the drug release profile from the formulation as per the requirement based on the apt selection of SD carriers and suitable technology. This review covers the comprehensive overview of all such formulations where SD technology is used to serve dual purpose rather than only the sole purpose of solubility enhancement. The SD approach has been successfully implemented for some of the poorly soluble herbal drugs and still there is a vast scope of advancement in that area. The current review will provide a broad outcome in the area of SD technology for modified release formulations along with the description of current status and future prospective of SD. The SD formed by dispersing drug within the conventional carrier to form ASD increases solubility, dissolution rate and bioavailability; whereas fourth generation hydrophobic carriers provide added advantage of controlled release (CR) or sustained release (SR) profile along with enhanced stability of SD. On the other frontier, pH dependant carriers enable the SD to achieve site specificity or delayed release (DR) profile.

Microfluidics for Drug Development: From Synthesis to Evaluation

Drug development is a long process whose main content includes drug synthesis, drug delivery, and drug evaluation. Compared with conventional drug development procedures, microfluidics has emerged as a revolutionary technology in that it offers a miniaturized and highly controllable environment for bio(chemical) reactions to take place. It is also compatible with analytical strategies to implement integrated and high-throughput screening and evaluations. In this review, we provide a comprehensive summary of the entire microfluidics-based drug development system, from drug synthesis to drug evaluation. The challenges in the current status and the prospects for future development are also discussed. We believe that this review will promote communications throughout diversified scientific and engineering communities that will continue contributing to this burgeoning field.

Synthesis and characterization of osmotic pump capsules containing polyoxyethylene and pH modifier to control the release of nifedipine

The aim of this study was to formulate osmotic pump capsules (OPCs) to control the release of nifedipine (NP). NP solid dispersion was prepared by solvent evaporation method. The prepared mixture of NP solid dispersion and various excipients were filled into the commercial HPMC hard capsule shells and then coated with cellulose acetate (CA) solution to form NP-OPC. The CA coating solution consisted of CA as semi-permeable membrane, and Poloxamer 188 as pore formers. The impact of addition agents, citric acid and pore formers on in vitro drug release were investigated. Furthermore, the study has highlighted the impact of paddle speed and the pH value of release media, on the release and compared the release with the commercial controlled release tablets. The in vitro drug release study indicated that drug release could reach 95% in 24 h with optimal formulation, and interestingly model fitting showed that the drug release behavior was closely followed to zero-order release kinetics. The pharmacokinetic studies were performed in rabbits with commercial controlled release tablets as reference, both preparations showed a sustained release effect. Compared with traditional preparation methods of OPCs, the new preparation process was simplified without the operation of laser drilling and the sealing process of capsule body and cap, which improved the feasibility of industrial production.

Advances in drug delivery systems: Work in progress still needed?

A new era of science and technology has emerged in pharmaceutical research with focus on developing novel drug delivery systems for oral administration. Conventional dosage forms like tablets and capsules are associated with a low bioavailability, frequent application, side effects and hence patient noncompliance. By developing novel strategies for drug delivery, researchers embraced an alternative to traditional drug delivery systems. Out of those, fast dissolving drug delivery systems are very eminent among pediatrics and geriatrics. Orally disintegrating films are superior over fast dissolving tablets as the latter are assigned with the risk of suffocation. Due to their ability of bypassing the dissolution and the first pass effect after oral administration, self-emulsifying formulations have also become increasingly popular in improving oral bioavailability of hydrophobic drugs. Osmotic devices enable a controlled drug delivery independent upon gastrointestinal conditions using osmosis as driving force. The advances in nanotechnology and the variety of possible materials and formulation factors enable a targeted delivery and triggered release. Vesicular systems can be easily modified as required and provide a controlled and sustained drug delivery to a specific site.

This work provides an insight of the novel approaches in drug delivery covering the critical comparison between traditional and novel “advanced-designed” systems.

Double-layered osmotic pump controlled release tablets of actarit: In vitro and in vivo evaluation

The aim of the study was to develop actarit double-layered osmotic pump tablets to overcome the weak points of actarit common tablets, such as short half-life and large plasma concentration fluctuations. Single factor experiment and orthogonal test were applied to optimize the formulation; the pharmacokinetic study was performed in beagle dogs adopting actarit common tablets as reference tablets. The optimal formulation was as follows: drug layer: 150 mg actarit, 240 mg PEO-N80, 50 mg NaCl; push layer: 140 mg PEO-WSR303, 20 mg NaCl; coating solution: 30 g cellulose acetate and 6 g PEG 4000 in 1000 ml 94% acetone solution, 60 mg coating weight gain. The pharmacokinetic study showed that T_max was prolonged by the contrast of commercial common tablets with constant drug release rate, but the bioavailability was equivalent. And a good in vivo–in vitro correlation of the actarit osmotic pump tablets was also established. The designed actarit osmotic pump tablets can be applied for rheumatoid arthritis, proposing a promising replacement for the marked common products.

Nano-suspension coating as a technique to modulate the drug release from controlled porosity osmotic pumps for a soluble agent

In controlled porosity osmotic pumps (CPOP), usually finding a single solvent with a capability to dissolve both film former (hydrophobic) and pore former (hydrophilic) is extremely challenging. Therefore, the aim of the present investigation was to tackle the issue associated with controlled porosity osmotic pump (CPOP) system using nano-suspension coating method. In the present study 4-Amino pyridine was used as a highly water soluble drug. In this method, a hydrophilic pore former (sucrose or mannitol) in nano range was suspended in polymeric coating solution using ball-mill. The performance of the prepared formulations was assessed in terms of D_12h (cumulative release percent after 12h), Dev_zero (mean percent deviation of drug release from zero order kinetic), t_L (lag time of the drug release) and RSQ_zero. The results revealed that gelling agent amount (HPMC E_15LV) in core and pore former concentration in SPM had crucial effect on SPM integrity. All the optimised formulations showed a burst drug release due to fast dissolving nature of the pore formers. Results obtained from scanning electron microscopy demonstrated the formation of nanopores in the membrane where the drug release takes place via these nanopores. Nano suspension coating method can be introduced as novel method in formulation of CPOPs.

Regenerated cellulose capsules for controlled drug delivery: Part IV. In-vitro evaluation of novel self-pore forming regenerated cellulose capsules

In the present work, the release mechanisms of active pharmaceutical ingredients (APIs) enclosed in self-pore forming regenerated cellulose (RC) two-piece hard shell capsules are described. The RC capsules were fabricated using a modified dip-coating approach, which yielded an assembled dosage form that was equivalent in size and shape to a conventional gelatin two-piece hard shell capsule. Drug release characteristics from RC capsules were evaluated using potassium chloride, diphenhydramine hydrochloride, tramadol hydrochloride, niacinamide, acetaminophen and ketoprofen as model APIs. The RC capsules act as a barrier coated reservoir device that releases the enclosed API at a zero order release rate. When comparing all the API's release behavior from RC capsules, a power-law relationship was observed between their zero-order release rates and their respective aqueous solubilities. Osmotic as well as diffusive mechanisms are involved in the release of the enclosed API. The osmotic mechanism's contribution to zero order release rate increases as the aqueous solubility of the tested APIs inside the capsule increases. The osmotic mediated flux and the apparent diffusivity of the APIs through the capsule wall is a competitive process and the osmotic mediated flux of the enclosed API begins to override its diffusivity through the capsule wall as the API solubility increases. This behavior is attributed to the wide range of pore sizes observed in RC membranes, from our prior analysis. The fluid permeability analysis shows that the RC capsules presented in this work may be better suited for osmotic drug delivery applications than conventional encapsulated systems described in the literature.