Formulation and evaluation of novel solid lipid microparticles as a sustained release system for the delivery of metformin hydrochloride

The low encapsulation efficiency of conventional solid lipid microparticles (SLMs) especially for hydrophilic drugs has remained a challenge to drug formulation experts. This work seeks to address the issue of inefficient delivery of metformin hydrochloride (MTH), a potent hydrophilic oral antihyperglycemic agent, using novel SLMs based on solidified reverse micellar solutions (SRMS) prepared by melt-emulsification using a lipid derived from Capra hircus and Phospholipon® 90H. Characterization based on size, morphology, zeta potential, polydispersity index, encapsulation efficiency (EE%), loading capacity (LC) and time-resolved stability were carried out on the SLMs. The in vitro release of MTH from the SLMs was performed in phosphate buffer (pH 7.4) while the in vivo antidiabetic properties were investigated in alloxan-induced diabetic rats. Stable, spherical and smooth SLMs were obtained. Loading of MTH into the SLMs had no effect on the surface charge of the particles. The SLMs with 1.0%w/w PEG 4000 resulted in significantly (p < 0.05) higher EE% while those with 2.0%w/w gave the least. The LC values ranged from 20.3 to 29.1 and 14.6 to 24.1 for SLMs containing 500 mg and 250 mg of MTH, respectively. The in vitro release studies revealed significant release of MTH from the SLMs whereas the in vivo antidiabetic studies indicated that novel SLMs containing 500 mg of MTH gave significantly (p < 0.05) higher glucose reduction than glucophage®. This research has shown that SLMs based on SRMS offer a new and better approach of delivering MTH, thus encouraging further development of this formulation.

Novel drug delivery system of plant extract for the management of diabetes: an antidiabetic study

CONTEXT

Moringa oleifera leaves have been reported to have antidiabetic, antitumor, hypotensive, anti-inflammatory, and diuretic properties as well as antibiotic, antitryponosomal, hypotensive, and anti-inflammatory activities. They are outstanding source of vitamins A, B, C, and also rich in calcium and protein.

OBJECTIVES

The aim of the study was to formulate Moringa oleifera powdered leaf tablets and to study the in vitro and in vivo properties of the herbal drug from the tablets.

MATERIAL AND METHODS

The Moringa oleifera powdered leaf was formulated into tablets by direct compression. The in vitro properties of the tablets were evaluated in terms of uniformity of weight, hardness, disintegration time, friability and dissolution rate. Also, the in vivo antidiabetic properties of Moringa oleifera tablets were studied using Wistar rats.

RESULTS AND DISCUSSION

The results of the tablets' weight uniformity gave percentage deviation that was below 5%. Tablet disintegration time ranged from 11.50 ± 0.11 to 14.90 ± 0.27 min. The tablets exhibited friability results lower than 2% and exhibited about 82% to 83% release of the extract at 15 min. In vivo antidiabetic studies showed that at 8 hr, about 54.4% and 40% of glucose reduction occurred in groups that received Moringa oleifera tablets and glibenclamide (Daonil®) respectively, while the negative control groups showed increased blood glucose level with time.

CONCLUSIONS

This study has shown that Moringa oleifera leaves formulated into tablets possess good physicochemical and antidiabetic properties in addition to being a supplement.

Potential enhancement of metformin hydrochloride in solidified reverse micellar solution-based PEGylated lipid nanoparticles targeting therapeutic efficacy in diabetes treatment

Metformin hydrochloride (MH) is a widely used oral biguanide antihyperglycemic (antidiabetic) drug with poor bioavailability which necessitates the development of novel drug delivery systems such as PEGylated solid lipid nanoparticles for improving its therapeutic activity. The aim of this study was to formulate, characterize and evaluate in vitro and in vivo pharmacodynamic properties of metformin-loaded PEGylated solid lipid nanoparticles (PEG-SLN) for improved delivery of MH. The lipid matrices (non-PEGylated lipid matrix and PEGylated lipid matrices) used in the formulation of both non-PEGylated (J0) and PEGylated SLNs (J10, J20, J40) were prepared by fusion using beeswax and Phospholipon ® 90H at 7:3 ratio with or without polyethylene glycol (PEG) 4000 (0, 10, 20 and 40% w/w), respectively. Representative lipid matrices (LM and PEG-LM) were loaded with MH by fusion and then characterized by differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectroscopy. The PEG-SLNs were prepared by high shear hot homogenization using the lipid matrices (5% w/w), drug (MH) (1.0% w/w), sorbitol (4% w/w) (cryoprotectant), Tween ® 80 (2% w/w) (surfactant) and distilled water (q.s to 100% w/w) (vehicle). The non-PEGylated and PEGylated SLNs (J0, J10, J20, J40)) were characterized with respect to encapsulation efficiency (EE%), loading capacity (LC), morphology by scanning electron microscopy (SEM), mean particle size (Zav) and polydispersity indices (PDI) by photon correlation spectroscopy (PCS), compatibility by FT-IR spectroscopy and in vitro drug release in biorelevant medium. Thereafter, in vivo antidiabetic study was carried out in alloxanized rats' model and compared with controls (pure sample of MH and commercial MH- Glucophage®)). Solid state characterizations indicated the amorphous nature of MH in the drug loaded-lipid matrices. The PEG-SLNs were mostly smooth and spherical nanoformulations with Zav and PDI of 350.00 nm and 0.54, respectively, for non-PEGylated SLNs, and in the range of 386.80-783.10 nm and 0.592 to 0.752, respectively, for PEGylated SLNs. The highest EE% and LC were noted in batch J20 and were 99.28% and 16.57, respectively. There was no strong chemical interaction between the drug and excipients used in the preparation of the formulations. The PEGylated SLN (batch J40) exhibited the highest percentage drug released (60%) at 8 h. The PEGylated SLNs showed greater hyperglycemic control than the marketed formulation (Glucophage ®) after 24 h. This study has shown that metformin-loaded PEGylated solid lipid nanoparticles could be employed as a potential approach to improve the delivery of MH in oral diabetic management, thus encouraging further development of the formulations.

Sustained-release liquisolid compact tablets containing artemether-lumefantrine as alternate-day regimen for malaria treatment to improve patient compliance

The present study aimed to develop low-dose liquisolid tablets of two antimalarial drugs artemether–lumefantrine (AL) from a nanostructured lipid carrier (NLC) of lumefantrine (LUM) and estimate the potential of AL as an oral delivery system in malariogenic Wistar mice. LUM-NLCs were prepared by hot homogenization using Precirol^® ATO 5/Transcutol^® HP and tallow fat/Transcutol^® HP optimized systems containing 3:1 ratios of the lipids, respectively, as the matrices. LUM-NLC characteristics, including morphology, particle size, zeta potential, encapsulation efficiency, yield, pH-dependent stability, and interaction studies, were investigated. Optimized LUM-NLCs were mixed with artemether powder and other dry ingredients and the resultant powder evaluated for micromeritics. Subsequent AL liquisolid tablets were tested for in vitro drug release and in vivo antiplasmodial activity in mice infected with Plasmodium berghei berghei (NK 65). Results showed that optimized LUM-NLC were stable, spherical, polydispersed but nanometric. Percentage yield and encapsulation efficiency were ~92% and 93% for Precirol^® ATO 5/Transcutol^® HP batch, then 81% and 95% for tallow fat/Transcutol^® HP batch while LUM was amorphous in NLC matrix. In vitro AL release from liquisolid compacts revealed initial burst release and subsequent sustained release. Liquisolid tablet compacts formulated with Precirol^® ATO 5/Transcutol^® HP-AL4 achieved higher LUM release in simulated intestinal fluid (84.32%) than tallow fat/Transcutol^® HP-BL3 (77.9%). Non-Fickian (anomalous) diffusion and super case II transport were the predominant mechanisms of drug release. Equal parasitemia reduction was observed for both batches of tablet compacts (~92%), superior to the reduction obtained with commercial antimalarial formulations: Coartem^® tablets (86%) and chloroquine phosphate tablets (66%). No significant difference (P<0.05) in parasite reduction between double (4/24 mg/kg) and single (2/12 mg/kg) strength doses of AL compacts was observed. Our result highlights that AL could be formulated in much lower doses (4/24 mg/kg), for once-in-two days oral administration to improve patient compliance, which is currently not obtainable with conventional AL dosage forms.

Pharmacodynamics of diclofenac from novel Eudragit entrapped microspheres

Effective clinical utilization of non-steroidal anti-inflammatory drugs such as diclofenac sodium (DS) is significantly limited by their ulcerogenic potential and poor bioavailability after oral administration, thus necessitating the need for a better carrier to minimize these obvious limitations. The objective of this study was to evaluate Eudragit® RS100/RL100 microspheres formulated by the solvent-evaporation technique for improved delivery of diclofenac. Three batches of (DF1, DF2 and DF3) microspheres were prepared using different ratios of Eudragit RS-100 and RL-100 polymers based on the solvent-evaporation method. The microspheres were characterized based on morphological properties, particle size analysis and encapsulation efficiency (EE%). In vitro release of DS was investigated in both 0.1 N HCl (pH 1.2) and phosphate-buffered saline (pH 7.4), while anti-inflammatory studies were evaluated in the rat model. Maximum EE% of 86.61 ± 0.11, 88.14 ± 0.16 and 85.50 ± 0.21 was obtained for DF1, DF2 and DF3, respectively. Discrete, smooth and brownish microspheres of size range 437 ± 0.01-479 ± 0.21 µm were obtained. Release of DS from the formulation depends on the polymer ratio. All the batches exhibited good anti-inflammatory activities. Microsphere formulations based on Eudragit® polymers would likely offer a reliable and alternative means of delivering DS orally.

Improved antimalarial activity of caprol-based nanostructured lipid carriers encapsulating artemether-lumefantrine for oral administration

BACKGROUND

Artemether and lumefantrine display low aqueous solubility leading to poor release profile; hence the need for the use of lipid-based systems to improve their oral bioavailability so as to improve their therapeutic efficacy.

AIM AND OBJECTIVE

The objective of this work was to utilize potentials of nanostructured lipid carriers (NLCs) for improvement of the oral bioavailability of artemether and lumefantrine combination and to evaluate its efficacy in the treatment of malaria. This study reports a method of formulation, characterization and evaluation of the therapeutic efficacies of caprol-based NLC delivery systems with artemether and lumefantrine.

METHOD

The artemether-lumefantrine co-loaded NLCs were prepared using the lipid matrix (5% w/w) (containing beeswax and Phospholipon® 90H and Caprol-PGE 860), artemether (0.1%w/w) and lumefantrine (0.6%w/w), sorbitol (4%w/w), Tween® 80(2%w/w as surfactant) and distilled water (q.s to 100%) by high shear homogenization and evaluated for physicochemical performance. The in vivo antimalarial activities of the NLC were tested in chloroquine-sensitive strains of Plasmodium berghei (NK-65) using Peter´s 4-day suppressive protocol in mice and compared with controls. Histopathological studies were also carried out on major organs implicated in malaria.

RESULTS

The NLC showed fairly polydispersed nano-sized formulation (z-average:188.6 nm; polydispersity index, PDI=0.462) with no major interaction occurring between the components while the in vivo study showed a gradual but sustained drug release from the NLC compared with that seen with chloroquine sulphate and Coartem®. Results of histopathological investigations also revealed more organ damage with the untreated groups than groups treated with the formulations.

CONCLUSION

This study has shown the potential of caprol-based NLCs for significant improvement in oral bioavailability and hence antimalarial activity of poorly soluble artemether and lumefantrine. Importantly, this would improve patient compliance due to decrease in dosing frequency as a sustained release formulation.

Biodegradable nanoparticles from prosopisylated cellulose as a platform for enhanced oral bioavailability of poorly water-soluble drugs

Bio-inspired nanotechnology-based strategies are potential platforms for enhanced dissolution and oral biovailability of poorly water-soluble drugs. In this study, a recently patented green biopolymer (Prosopis africana gum, PG) was compatibilized with microcrystalline cellulose (MCC), a conventional polysaccharide, via thermo-regulated coacervation to obtain PG-MCC (1:0, 1:1, 1:2, 2:1, and 0:1) rational blends and the nanoparticles developed with optimized (1:1) biocomposites (termed "prosopisylated cellulose") by combined homogenization-nanoprecipitation technique was engineered as a high circulating system for improved oral bioavailability of griseofulvin (GF), a model Biopharmaceutics Classification System (BCS) Class-II drug. The effects of biopolymer interaction on morphological and microstructural properties of drug-free biocomposites obtained were investigated by Fourier transform infra-red spectroscopy, scanning electron microscopy and x-ray diffractometry, while the physicochemical properties and in-vivo pharmacokinetics of GF-loaded nanoparticles were also ascertained. Optimized biocomposites revealed inter-molecular and intra-molecular hydrogen bonding between the hydroxyl group of MCC and polar components of PG, as well as reduction in crystallinity of MCC. Griseofulvin-loaded nanoparticles were stable, displayed particles with relatively smooth surfaces and average size of 26.18 ± 0.94 . nm, with zeta potential and polydispersity index of 32.1 ± 0.57 mV and 0.173 ± 0.06, respectively. Additionally, the nanoparticles showed good entrapment efficiency (86.51 ± 0.93 %), and marked improvement in griseofulvin dissolution when compared to free drug, with significantly (p < 0.05) higher GF release in basic than acidic PEG-reinforced simulated bio-microenvironments. Besides, x-ray diffractogram of GF-loaded nanoparticles showed amorphization with few characteristic peaks of GF while infra-red spectrum indicated broader principal peaks of GF and components compatibility. Furthermore, GF-loaded nanoparticles showed low plasma clearance with three-fold increase in systemic bioavailability of griseofulvin compared with free drug. These results showed that prosopisylated cellulose nanoparticles would be a facile approach to improve oral bioavailability of BCS class-II drugs and can be pursued as a new versatile drug delivery platform.

Formulation and Evaluation of Ibuprofen Loaded Lipospheres for Effective Oral Drug Delivery

Ibuprofen (IBU) is an anti-inflammatory drug characterized by low solubility and bioavailabilty. This study was to develop IBU-liposphere and investigated for in vitro and in vivo performance. IBU free base was incorporated into lipospheres based on micronized beeswax and Phospholipon® 90H in the ratio of (1:3), via hot emulsification. IBU-loaded lipospheres were characterized based on morphology, encapsulation efficiency (EE%), and in vitro drug release. Analgesic, anti-inflammatory activities and the pharmacokinetics were similarly evaluated. Minimum and maximum encapsulation efficiency (EE%) of 89.4 and 97.9% were obtained for lipospheres A1 and A3, respectively. Stable, spherical and smooth lipospheres of size range 101 ± 0.30 to 178 ± 0.30 ?m were obtained. Minimum and maximum release of 75 and 96.9% were obtained for A1 and A3, respectively. Significant (p<0.005) analgesic and anti-inflammatory activities were achieved with prolong plasma concentration. IBU-lipospheres based on beeswax and phospholipid could be explored as an alternative drug delivery system.Dhaka Univ. J. Pharm. Sci. 14(1): 17-27, 2015 (June)

Formulation and Evaluation of Cola acuminata Gum-based Mucoadhesive Sustained-release Matrix Tablets of Diclofenac Sodium

OBJECTIVE

This study aimed to evaluate Cola acuminata gum (CAG) for the formulation of mucoadhesive sustained-release matrix tablets of diclofenac sodium.

METHODS

Different batches of granules containing CAG and 100 mg of DS in ratios 0.5:1, 1:1, 2:1, and 3:1 were prepared, compressed into tablets, and evaluated for mucoadhesive strength, swelling index, and drug release in SGF (pH 1.2) and SIF (pH 7.4).

RESULTS

Swelling indices and mucoadhesive strengths of the tablets were pH-dependent. Swelling indices of 56 ± 2.03 to 121 ± 2.19% and mucoadhesive strengths of 7.25 ± 1.45 to 15.43 ± 2.71 g/cm2 obtained at pH 7.4 were significantly higher (p<0.05) than swelling indices of 25 ± 2.43 to 47 ± 3.15% and mucoadhesive strengths of 5.52 ± 0.76 to 9.22 ± 1.95 g/cm2 obtained at pH 1.2. The percentage release of DS from the matrix tablets at pH 1.2 after 2 h (T2h) was insignificant. However, the percentage of drug release at pH 7.4 was significant for all the batches and dependent on the CAG concentration. The drug release was in the order of batches containing 3 g (80.44 ± 7.75) < 2 g (86.35 ± 5.65) < 1 g (90.08 ± 6.14) < 0.5 g (99.70 ± 3.90). The time for maximum drug release was 7 h (T7h) for CAG containing 0.5 g and 10 h (T10h) for other batches.

CONCLUSION

This study showed that CAG could be useful for mucoadhesive sustained drug delivery.