Simultaneous delivery of Nifedipine and Metoprolol tartarate using sandwiched osmotic pump tablet system

Osmotic Pump Drug Delivery Systems-A Comprehensive Review

In the last couple of years, novel drug delivery systems (NDDS) have attracted much attention in the food and pharmaceutical industries. NDDS is a broad term that encompasses many dosage forms, one of which is osmotic pumps. Osmotic pumps are considered to be the most reliable source of controlled drug delivery, both in humans and in animals. These pumps are osmotically controlled and release active agents through osmotic pressure. To a large extent, drug release from such a system is independent of gastric fluids. Based on such unique properties and advantages, osmotic pumps have made their mark on the pharmaceutical industry. This review summarizes the available osmotic devices for implantation and osmotic tablets for oral administration.

Preparation and in Vitro Evaluation of Osmotic-Pump Lorcaserin-hydrochloride Controlled-Release Tablets

Long-term and constant-release osmotic-pump lorcaserin hydrochloride controlled-release tablets (OP LH CRTs) were prepared, to investigate the influencing factors of LH release and optimize the formulation. The mechanism of release of LH from OP LH CRTs in vitro was investigated. By establishing a high-efficiency method for measuring LH release in vitro, and optimizing it by single-factor and orthogonal experiments, the best formulation of OP LH CRTs was determined. Then, the optimal prescription of OP LH CRTs was: LH = 20.8 mg; mannitol = 100 mg, microcrystalline cellulose = 125 mg; magnesium stearate = 5 mg; cellulose acetate = 3%; polyethylene glycol 400 = 10%; dibutyl phthalate = 10%; Wetting agent and binder was 3% polyvinyl pyrrolidone (PVP) K30 ethanol solution; aperture diameter = 0.8 mm; the coating gained 3% weight. And finally, prepared OP LH CRTs were released at a constant rate in vitro and sustained for 16 h with good reproducibility between batches. Using an orthogonal experimental design, OP LH CRTs with remarkable zero-order release characteristics within 16 h were obtained, and formulation optimization was realized.

Visualized analysis and evaluation of simultaneous controlled release of metformin hydrochloride and gliclazide from sandwiched osmotic pump capsule

The aim of this study was to develop the Metformin Hydrochloride and Gliclazide (MH-GZ) sandwiched osmotic pump capsule which could overcome the problems associated with short half-life and burst release. The system could deliver drugs with different solubility simultaneously at zero-order rate, in which MH-GZ were filled in both sides of the push layer respectively. The single factor and orthogonal test were employed to obtain the optimized formulation with the evaluation index of similarity factor (ƒ₂). R language was used to visualized analyze the main influence factors of drug release and their correlations. Pharmacokinetic study was performed in beagle dogs compared to the marketed conventional product, which showed decreased C_max, prolonged T_max, and improved bioavailability, independent of pH and agitational speed but related to osmotic pressure differences across the semi permeable membrane. The designed sandwiched osmotic pump capsule proposed a promising substitute for the marketed product for the treatment of type 2 diabetes.

Preparation and in vitro/in vivo evaluation of azilsartan osmotic pump tablets based on the preformulation investigation

The objective of this study was to design and evaluate azilsartan osmotic pump tablets. Preformulation properties of azilsartan were investigated for formulation design. Azilsartan osmotic pump tablets were prepared by incorporation of drug in the core and subsequent coating with cellulose acetate and polyethylene glycol 4000 as semi-permeable membrane, then drilled an orifice at the center of one side. The influence of different cores, compositions of semipermeable membrane and orifice diameter on azilsartan release were evaluated. The formulation of core tablet was optimized by orthogonal design and the release profiles of various formulations were evaluated by similarity factor (f₂). The optimal formulation achieved to deliver azilsartan at an approximate zero-order up to 14 h. The pharmacokinetic study was performed in beagle dogs. The azilsartan osmotic pump tablets exhibited less fluctuation in blood concentration and higher bioavailability compared to immediate-release tablets. Moreover, there was a good correlation between the in vitro dissolution and in vivo absorption of the tablets. In summary, azilsartan osmotic pump tablets presented controlled release in vitro, high bioavailability in vivo and a good in vitro-in vivo correlation.

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.

The development and evaluation of a subcutaneous infusion delivery system based on osmotic pump control and gas drive

A novel, self-administration drug delivery system for subcutaneous infusion was developed and evaluated. The device includes two main components: an osmotic tablet controlled gas actuator and a syringe catheter system. The sodium carbonate in the osmotic pump tablet will release into the surround citric acid solution and produce CO₂ gas, which will drive the drug solution into subcutaneous tissue. The key formulation factors of the osmotic tablet that would influence the infusion profiles of the device were investigated by single factor exploration. The formulation was optimized via a response surface methodology. With an 18 ± 4 min of lag time, the delivery system was able to infuse at an approximate zero-order up to 5.90 ± 0.37 h with a precision of 9.0% RSD (n = 6). A linear correlation was found for the infusion profile and the fitting equation was Y = 0.014X - 0.004 (r = 0.998). A temperature change of 4 °C was found to modify the flow rate by about 12.0%. In vivo results demonstrated that the present subcutaneous infusion device was similar to the commercial infusion pump, and it could bring a long and constant ampicillin plasma level with minimized fluctuations.

Synchronous delivery of felodipine and metoprolol tartrate using monolithic osmotic pump technology

The synchronous sustained-release of two drugs was desired urgently for patients needing combination therapy in long term. However, sophisticated technologies were used generally to realize the simultaneous delivery of two drugs especially those with different physico-chemical properties. The purpose of this study was to obtain the concurrent release of felodipine and metoprolol tartrate, two drugs with completely different solubilities, in a simple monolithic osmotic pump system (FMOP). Two types of blocking agents were used in monolithic osmotic pump tablets and the synchronous sustained-release of FMOP was acquired in vitro. The tablets were also administered to beagle dogs and the plasma levels of FMOP were determined by HPLC-MS/MS. The pharmacokinetic parameters were calculated using a non-compartmental model. Cmax of both felodipine and metoprolol from the osmotic pump tablets were lower, tmax and mean residence time of both felodipine and metoprolol from the osmotic pump tablets were longer significantly than those from immediate release tablets. These results verified prolonged release of felodipine and metoprolol tartrate from osmotic pump formulations. The similar absorption rate between felodipine and metoprolol in beagles was also obtained by this osmotic pump formulation. Therefore, it could be supposed that the accordant release of two drugs with completely different solubilities may be realized just by using monolithic osmotic pump technology.

Development and uniform evaluation of ropinirole osmotic pump tablets with REQUIP XL both in vitro and in beagle dogs

REQUIP XL, prolonged release formulation of ropinirole hydrochloride (RH) in market, could release ropinirole constantly and showed satisfactory therapeutic effect and good compliance. REQUIP XL was composed of more than 10 kinds of excipients and prepared by Geomatrix technology, which was complex and laborious. The purpose of this study was to obtain a dosage form of RH with similar in vitro release profile and bioequivalence in vivo compared to REQUIP XL. Osmotic pump tablet combined with fast release phase was selected as the delivery system of RH and similar release curves were obtained in different media. The tablets were also administered to beagle dogs and the pharmacokinetic parameters were calculated using a non-compartmental model. C_max, t_max, mean residence time (MRT), and area under the curve from 0 to 24 h (AUC_0-24) were 3.97 ± 0.53 ng/mL, 3.58 ± 0.49 h, 8.29 ± 0.93 h, and 35.20 ± 8.11 ng/mL ċ h for ropinirole osmotic pump tablets (ROPT) and 4.15 ± 1.07 ng/mL, 2.92 ± 0.49 h, 7.84 ± 1.09 h, and 34.34 ± 10.06 ng/mL ċ h for REQUIP XL. The log-transformed mean C_max and AUC_0-24 of ROPT were about 92.15% and 102.49% relative to that of REQUIP XL, respectively. The 90% confidence intervals of C_max and AUC_0-24 for ROPT were 75.69-115.31% and 88.89-122.30%, respectively. So it could be concluded that ROPT was uniform with REQUIP XL both in vitro and in beagles and the release profiles of Geomatrix technology may be obtained by osmotic pump combined with fast release technology.

Micro-porous surfaces in controlled drug delivery systems: design and evaluation of diltiazem hydrochloride controlled porosity osmotic pump using non-ionic surfactants as pore-former

The major problem associated with conventional drug delivery systems is unpredictable plasma concentrations. The aim of this study was to design a controlled porosity osmotic pump (CPOP) of diltiazem hydrochloride to deliver the drug in a controlled manner. CPOP tablets were prepared by incorporation of drug in the core and subsequent coating with cellulose acetate as semi-permeable membrane. Non-ionic surfactants were applied as pore-formers as well. The effect of pore-formers concentration on the in vitro release of diltiazem was also studied. The formulations were compared based on four comparative parameters, namely, total drug released after 24 h (D24 h), lag-time (tL), squared correlation coefficient of zero order equation (RSQzero) and mean percent deviation from zero order kinetic (MPDzero). Results of scanning electron microscopy studies exhibited formation of pores in the membrane from where the drug release occurred. It was revealed that drug release rate was directly proportional to the concentration of the pore-formers. The value of D24 h in the formulations containing Tween 80 (10%) and Brij 35 (5%) were found to be more than 94.9%, and drug release followed zero order kinetic (RSQzero > 0.99 and MPDzero < 8%) with acceptable tL (lower than 1 h).

Feasibility of optimizing trimetazidine dihydrochloride release from controlled porosity osmotic pump tablets of directly compressed cores

The aim of this study was to develop and optimize Trimetazidine dihydrochloride (TM) controlled porosity osmotic pump (CPOP) tablets of directly compressed cores. A 2³ full factorial design was used to study the influence of three factors namely: PEG400 (10% and 25% based on coating polymer weight), coating level (10% and 20% of tablet core weight) and hole diameter (0 “no hole” and 1 mm). Other variables such as tablet cores, coating mixture of ethylcellulose (4%) and dibutylphthalate (2%) in 95% ethanol and pan coating conditions were kept constant. The responses studied (Y_i) were cumulative percentage released after 2 h (Q%_2h), 6 h (Q%_6h), 12 h (Q%_12h) and regression coefficient of release data fitted to zero order equation (RSQ_zero), for Y₁, Y₂, Y₃, and Y₄, respectively. Polynomial equations were used to study the influence of different factors on each response individually. Response surface methodology and multiple response optimization were used to search for an optimized formula. Response variables for the optimized formula were restricted to 10% ⩽ Y₁ ⩽ 20%, 40% ⩽ Y₂ ⩽ 60%, 80% ⩽ Y₃ ⩽ 100%, and Y₄ > 0.9. The statistical analysis of the results revealed that PEG400 had positive effects on Q%2h, Q%6h and Q%12h, hole diameter had positive effects on all responses and coating level had positive effect on Q%_6h, Q%_12h and negative effect on RSQ_zero. Full three factor interaction (3FI) equations were used for representation of all responses except Q%_2h which was represented by reduced (3FI) equation. Upon exploring the experimental space, no formula in the tested range could satisfy the required constraints. Thus, direct compression of TM cores was not suitable for formation of CPOP tablets. Preliminary trials of CPOP tablets with wet granulated cores were promising with an intact membrane for 12 h and high RSQ_zero. Further improvement of these formulations to optimize TM release will be done in further studies.

Biodegradable core-shell carriers for simultaneous encapsulation of synergistic actives

Simultaneous encapsulation of multiple active substances in a single carrier is essential for therapeutic applications of synergistic combinations of drugs. However, traditional carrier systems often lack efficient encapsulation and release of incorporated substances, particularly when combinations of drugs must be released in concentrations of a prescribed ratio. We present a novel biodegradable core-shell carrier system fabricated in a one-step, solvent-free process on a microfluidic chip; a hydrophilic active (doxorubicin hydrochloride) is encapsulated in the aqueous core, while a hydrophobic active (paclitaxel) is encapsulated in the solid shell. Particle size and composition can be precisely controlled, and core and shell can be individually loaded with very high efficiency. Drug-loaded particles can be dried and stored as a powder. We demonstrate the efficacy of this system through the simultaneous encapsulation and controlled release of two synergistic anticancer drugs using two cancer-derived cell lines. This solvent-free platform technology is also of high potential value for encapsulation of other active ingredients and chemical reagents.

Osmotic drug delivery system as a part of modified release dosage form

Conventional drug delivery systems are known to provide an immediate release of drug, in which one can not control the release of the drug and can not maintain effective concentration at the target site for longer time. Controlled drug delivery systems offer spatial control over the drug release. Osmotic pumps are most promising systems for controlled drug delivery. These systems are used for both oral administration and implantation. Osmotic pumps consist of an inner core containing drug and osmogens, coated with a semipermeable membrane. As the core absorbs water, it expands in volume, which pushes the drug solution out through the delivery ports. Osmotic pumps release drug at a rate that is independent of the pH and hydrodynamics of the dissolution medium. The historical development of osmotic systems includes development of the Rose-Nelson pump, the Higuchi-Leeper pumps, the Alzet and Osmet systems, the elementary osmotic pump, and the push-pull system. Recent advances include development of the controlled porosity osmotic pump, and systems based on asymmetric membranes. This paper highlights the principle of osmosis, materials used for fabrication of pumps, types of pumps, advantages, disadvantages, and marketed products of this system.

In vitro and in vivo evaluation of gliclazide push-pull osmotic pump coated with aqueous colloidal polymer dispersions

The objective of present work was to design and evaluate gliclazide push-pull osmotic pump (PPOP) coated with aqueous colloidal polymer dispersions-Eudragit(®) RL 30D and Eudragit(®) RS 30D. The influence of diacetin, diethyl phthalate (DEP), dibutyl sebacate (DBS) and triethyl citrate (TEC) on the free Eudragit(®) RL 30D and Eudragit(®) RS 30D films as plasticizers on drug release were studied. Among these four plasticizers, diacetin offered the smoothest surface of the cast films, and it displayed greatest water vapor transmission coefficient. Free RL and RS films with diacetin also exhibited greatest erosion compared with the other three plasticizers. On the other hand, TEC, DEP and DBS showed greater water absorption. When compared with CA-coated gliclazide PPOP, Eudragit-coated ones showed a f(2) factor of 71.7, indicating the similarity between the release profile of the two formulations. The prepared Eudragit-coated gliclazide PPOP showed typical Zero-order release characteristics, with R being 0.9953. In the in vivo evaluation, the mean relative oral bioavailability of Eudragit-coated PPOP compared to CA-coated ones was 106.9%, demonstrating good bioequivalence. Both of their in vitro-in vivo correlation (IVIVC) showed linear relationship, with R(2) being 0.9955 (Eudragit-coated PPOP) and 0.9987 (CA-coated PPOP), respectively. These results suggested that PPOP coated with Eudragit(®) RL 30D and RS 30D could overcome drawbacks of organic solution coating and promote the development of PPOP.

Development and evaluation of controlled porosity osmotic pump for nifedipine and metoprolol combination

Background

A system that can deliver multi-drug at a prolonged rate is very important for the treatment of various chronic diseases such as diabetes, asthma and heart disease. Controlled porosity osmotic pump tablet (CPOP) system was designed to deliver Nifedipine (NP) and Metoprolol (MP) in a controlled manner up to 12 h. It was prepared by incorporating drugs in the core and coated with various types (PVP, PEG-400 and HPMC) and levels (30, 40 and 50% w/w of polymer) of pore former at a weight gain of 8, 12 & 15%.

Results

Formulation variables like type and level of pore former and percent weight gain of membrane was found to affect the drug release from the developed formulations. Drug release was inversely proportional to the membrane weight but directly related to the level of pore former. Burst strength of the exhausted shell was inversely proportional to the level of pore former, but directly affected by the membrane weight. Results of scanning electron microscopy (SEM) studies showed the formation of pores in the membrane from where the drug release occurred. Dissolution models were applied to drug release data in order to establish the mechanism of drug release kinetics. In vitro release kinetics was subjected to superposition method to predict in vivo performance of the developed formulation.

Conclusion

The developed osmotic system is effective in the multi-drug therapy of hypertension by delivering both drugs in a controlled manner.