Journal of microencapsulation
J Microencapsul. 2012 Nov 28;: 23190167
Sree Harsha, Mahesh Attimard, Tanveer A Khan, Anroop B Nair, Bandar E Aldhubiab, Sibghatullah Sangi, Arshia Shariff
Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University , Al-Ahsa 31982 , Saudi Arabia.
Mucoadhesive microspheres of sitagliptin (SITCM), a new anti-diabetic drug was prepared with carbopol 934 P using Buchi B-90 nano spray drier and optimized to analyse the key effects and relations of three factors on formulation of SITCM were studied. The appearance of the microspheres was found to be shriveled to nearly spherical, with a narrow size of 2-8 µm. The drug loading and percentage yield was found to be 73 ± 0.2% and 92 ± 0.3%, respectively. In vitro release indicated Korsmeyer-Peppas pattern mucoadhesion of SITCM-8 was found to be 7.8 ± 0.3 h. In vivo studies in rats suggest that the sitagliptin was retained in the gastrointestinal tract for an extended period of time (∼12 h) and control group was reduced significantly (∼4 h). This study concludes that the mucoadhesive microsphere could be one of the most appropriate drug delivery approaches for the successful delivery of sitagliptin.
J Microencapsul. 2012 Nov 27;: 23181625
Comparative studies of poly(ε-caprolactone) and poly(D,L-lactide) as core materials of polymeric micelles.
Department of Biomedical Engineering, Faculty of Engineering, Mahidol University , 25/25 Phutthamonthon, Nakhon Pathom 73170 , Thailand.
Polymeric micelles have been successfully used to deliver a variety of therapeutic agents. Nonetheless, several limitations and considerations must be clarified and well-studied to achieve the highest therapeutic effect. In this study, a series of methoxy poly(ethylene glycol)-block-poly(ε-caprolactone)(PEG-b-PCL) and methoxy poly(ethylene glycol)-block-poly(D,L-lactide)(PEG-b-PLA) with varying molecular weight (MW) of hydrophobic core segment were synthesized. These block copolymers can form micelle with PCL or PLA as core-forming blocks and PEG as a coronal material. The effect of MW on micelle size and critical micelle concentration (CMC) was studied. DOX (DOX) was encapsulated inside the micelle core. Drug-loading content and size of micelles were studied. Drug release studies inside cells were evaluated by confocal laser scanning microscopy. In summary, the PLA core which is less hydrophobic than PCL showed higher CMC, smaller micelle size and faster DOX release inside nucleus.
J Microencapsul. 2012 Nov 8;: 23137195
School of Life Sciences and Biotechnology, Korea University , Seoul , Korea.
Disaccharide glycosides synthesised from food grade resources consist of the hydrophilic head group of maltose or lactose and provide better hydrophilic-lipophilic balance (HLB = 12) to the long alkyl chain derived from palm oil (PO) and palm kernel oil (PKO). Maltoside provides more flexibility in the vesicle's membrane because of its low packing density in the bilayer membrane compared to lactoside. The bending of the molecular structure in maltose form a less compact assembly for maltoside, whereas lactose is more linear in shape. Apart from hydrophilic moieties, packing behaviour was also governed by the hydrophobic moieties. PO has higher degree of unsaturation compared to PKO, thus providing higher fluidity in the bilayer membrane. Vesicle with high membrane flexibility is easier to disintegrate and deform to enhance drug penetration into the skin. Results showed that the glycosides delivered vitamin E (VE) into deeper skin layer at least two-fold higher than free VE.
J Microencapsul. 2012 Nov 8;: 23137194
College of Pharmacy, Pusan National University , Busan 609-735 , Republic of Korea.
A robust experimental design method was developed using a response surface methodology and models to facilitate the development process of retinol solid lipid nanoparticles (SLNs). The SLNs were evaluated to determine how different parameters including lipid and surfactant affect size and encapsulation efficiency. This was conducted using factorial analysis and a robust design (RD) method was used to achieve optimal formulations. Two models were developed based on the RD principle and both mean and variance of the response characteristics were estimated functionally using the least squares method. They proved useful in formulation studies aiming to develop optimum by allowing a systematic and reliable design method. A model for maximizing the overall desirability represented by the geometric mean of all objectives was found to provide a better solution. The newly designed method provides useful information to characterize significant factors and obtain optimum formulations, thereby allowing a systematic and reliable design method.
J Microencapsul. 2012 Oct 25;: 23098577
Pharmaceutical Sciences Laboratory , Onyx Pharmaceuticals, 249 E Grand Avenue, South San Francisco, CA 94080 , USA.
Sustained-release albumin microspheres (MSs) can be obtained by chemically cross-linking albumin. However, a significant challenge is preventing the cross-linking of the active pharmaceutical (protein or small molecule) ingredient (API) with the MS matrix. To prevent cross-linking of the API with the albumin matrix, a smart "solution cross-linking-microencapsulation" method was developed which involves cross-linking albumin solution with glutaraldehyde first, neutralizing any excess glutaraldehyde with sodium bisulphite, followed by the addition of API and finally spray drying. Using lysozyme as model API, MS formulations FL1 and FL2 were prepared and characterized. Physicochemical characterization using FT-IR and bioactivity evaluation indicate that microencapsulated API did not undergo any significant change in its native structure and the bioactivity was preserved during the formulation processing. Preliminary immunogenicity potential of the cross-linked albumin matrix determined by in vivo studies did not show any significant increase in antigen-specific serum-IgG levels, implying safety and biocompatibility of the cross-linked albumin matrix.
J Microencapsul. 2012 Oct 25;: 23094609
Effect of antioxidants on the stability of ONO-1301, a novel long-acting prostacyclin agonist, loaded in PLGA microspheres.
Department of Clinical Pharmaceutics, Faculty of Pharmaceutical Sciences, Mukogawa Women's University , Hyogo , Japan.
The purpose of this study was to investigate the physicochemical stability of ONO-1301 in poly(lactide-co-glycolide) microspheres (PLGA MS) under storage for 28 days in the absence or presence of butylated hydroxytoluene (BHT) or α-tocopherol as antioxidant. First, we observed the hydrolysed product:(i) in acidic solution and oxidized product and (ii) in PLGA MS under storage in HPLC study, each structure was determined by liquid chromatography-nuclear magnetic resonance/mass spectrometry. Second, ONO-1301-loaded PLGA MS containing 10% BHT was shown to be superior to ONO-1301-loaded PLGA MS without BHT, in the standpoint of the stability under storage or in vitro drug-release test, and AUC(0-28) following subcutaneous injection in rats. Finally, ONO-1301-loaded PLGA MS with 10% BHT were demonstrated to be significantly more effective than ONO-1301-loaded PLGA MS without BHT in a murine sponge model of angiogenesis. In conclusion, BHT is an effective antioxidant on the stability of ONO-1301 in PLGA MS under storage.
J Microencapsul. 2012 Oct 25;: 23094608
Synthesis and characterization of polyurethane-urea microcapsules containing galangal essential oil: statistical analysis of encapsulation.
Alexander V Podshivalov, Sergei Bronnikov, Vjacheslav V Zuev, Thichanee Jiamrungraksa, Sireerat Charuchinda
National Research University of Information Technologies, Mechanics and Optics , Kronverkskiy prospekt 49, 197101 Sankt Petersburg , Russian Federation.
Galangal essential oil (GEO) is known to possess antimicrobial activity (e.g. against Staphylococcus aureus). A way to increase oil lifetime in plants is encapsulation in polyurethane-urea (PUU) microcapsules. In this study, PUU microcapsules with GEO were synthesized by interfacial polymerization at oil-water interface in oil-water emulsion. A statistical analysis of the microcapsule size was successfully applied for characterization of the encapsulation process. Using the model of reversible aggregation, it was shown that the process of encapsulation takes place in the conditions of thermodynamic control. The polymerization conditions (agitation rate in the range 2000-10 000 rpm/min) are the key factors that affect the mean microcapsule size of primary capsules formed during encapsulation. Two complementary processes were determined the mean capsule size during a transformation of these primary microcapsules: break-up and coalescence of oil droplets in the oil-in-water emulsion. The agitation rate does not influence the coalescence of the oil droplets, but the threshold value of agitation speed (in this system 4000 rpm/min) does exist and that is what strongly increases break-up of oil droplets. The higher agitation rate resulted in smaller size of microcapsules (mean diameter decreasing from 5.6 to 4.9 µm for primary capsules and from 13.8 to 9.8 µm for secondary capsules) and with a narrower size distribution. The last mode of encapsulation allows the more effective use the shell material for encapsulating of larger amount of oil.
J Microencapsul. 2012 Oct 22;: 23088321
Department of Beauty Stylist, Yeonsung University , Gyeonggido 430-749 , Korea.
We prepared p-phenylenediamine (PDA)-incorporated nanoparticles using hyaluronic acid (HA). PDA-incorporated HA nanoparticles have spherical shapes and sizes were less than 300 nm. The results of FT-IR spectra indicated that PDA-incorporated HA nanoparticles were formed by ion-complex formation between amine group of PDA and carboxyl group of HA. Furthermore, powder-X-ray diffractogram (XRD) measurement showed that intrinsic crystalline peak of PDA disappeared by formation of nanoparticle with HA at XRD measurement. These results indicated that PDA-incorporated HA nanoparticles were formed by ion-complex formation. At drug release study, the higher PDA contents induced faster release rate from nanoparticles. PDA-incorporated nanoparticles showed reduced intrinsic toxicity against HaCaT human keratinocyte cells at MTT assay and apoptosis assay. We suggest that PDA-incorporated HA nanoparticles are promising candidates for novel permanent hair dye.
J Microencapsul. 2012 Oct 22;: 23088320
Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Santiago de Compostela, Campus Sur , 15782 Santiago de Compostela , Spain.
This article describes the development of a freeze-dried formulation of chitosan (CS) nanocapsules containing docetaxel (DCX) and the evaluation of its efficacy in the NCI-H460 cancer cell line. More specifically, two prototypes of nanocapsules differing in their coating, CS alone or in combination with poloxamer 188 were developed using the solvent displacement technique. These prototypes (150 nm and +45 mV) exhibited high encapsulation efficiencies of DCX (78%) and very similar release profiles. The nanocapsules made of solely CS could be freeze-dried and reconstituted without altering their particle size distribution. CS nanocapsules were tested for their ability to deliver intracellularly the anticancer drug DCX. The results showed that CS nanocapsules maintained the antiproliferative effect of the drug and that it was not affected by the freeze-drying process. Moreover, it was found that this cytostatic effect of DCX was related to its intracellular delivery in the cancer cells.
J Microencapsul. 2012 Oct 18;: 23078151
Cytotoxicity and antitumour activity of 5-fluorouracil-loaded polyhydroxybutyrate and cellulose acetate phthalate blend microspheres.
Department of Pharmacology, Soniya Education Trust's College of Pharmacy , Sangolli Rayanna Nagar, Dharwad 580 002, Karnataka , India.
Pharmacokinetics, biodistribution and antitumour activity of 5-fluorouracil (5-FU)-loaded polyhydroxybutyrate (PHB) and cellulose acetate phthalate (CAP) blend microspheres were investigated in chemically induced colorectal cancer in albino male Wistar rats and compared with pristine 5-FU given as a suspension. The microspheres were characterised for particle size, encapsulation efficiency, in vitro release and in vitro cytotoxicity on human HT-29 colon cancer cell line. Spherical particles with a mean size of 44 ± 11 µm were obtained that showed sustained release of 5-FU. A high concentration of 5-FU was achieved in colonic tissues and significant reduction in tumour volume and multiplicity were observed in animals treated with 5-FU-loaded microspheres. The decreased levels of plasma albumin, creatinine, leucocytopenia and thrombocytopenia were observed in animals for 5-FU microspheres compared to the standard 5-FU formulation. The results suggest the extended release of 5-FU from the PHB-CAP blend microspheres in colonic region to enhance the antitumour efficacy.
J Microencapsul. 2012 Oct 18;: 23078109
College of Pharmacy, Ewha Womans University , 52 Ewhayeodae-gil, Sedaemun-gu, Seoul 120-750 , Korea.
The objective of this study was to apply the specific acid-catalysed hydrolysis of ethyl acetate to completing solvent extraction during an emulsion-based microencapsulation process. The dispersed phase consisting of poly-D,L-lactide-co-glycolide and ethyl acetate was emulsified in an acid catalyst containing aqueous phase. Catalytic hydrolysis of ethyl acetate led to its continual leaching from the dispersed phase of the emulsion, thereby triggering microsphere hardening with high efficiency. Ketoprofen was successfully encapsulated into microspheres via this technique, and liquid chromatography-mass spectrometry showed that its structural integrity was preserved during microencapsulation. Compared to typical solvent extraction approaches, the acid-catalysis technique helped minimize the consumption of a quench liquid. Also, the resultant microspheres displayed excellent dispersibility and decreased propensity for aggregation. Furthermore, the new method provided better drug encapsulation efficiency and lower levels of residual ethyl acetate in microspheres. In conclusion, the acid-catalysis approach had great potential for the preparation of versatile microspheres and nanoparticles.
J Microencapsul. 2012 Oct 12;: 23057661
Sustained-release diclofenac potassium-loaded solid lipid microparticle based on solidified reverse micellar solution: in vitro and in vivo evaluation.
Department of Pharmaceutical Technology and Industrial Pharmacy, University of Nigeria , Nsukka 410001 , Nigeria.
Objective: To formulate sustained-release diclofenac potassium-loaded solid lipid microparticles (SLMs) based on solidified reverse micellar solution (SRMS) and to evaluate the in vitro and in vivo properties. Methods: SRMS consisting of mixtures of Phospholipon® 90H and Softisan® 154 were used to formulate diclofenac potassium-loaded SLMs. Characterization based on the particle size and morphology, stability and encapsulation efficiency (EE%) were carried out on the SLMs. In vitro release was carried out in simulated intestinal fluid (pH 7.5). Anti-inflammatory and ulcerogenic properties were studied using rats. Results: Maximum EE% of 95%, 94% and 93% were obtained for SLMs formulated with SRMS 1:1, 2:1 and 1:2, respectively. In vitro release showed about 85-90% drug release at 13 h. Diclofenac potassium-loaded SLMs showed good anti-inflammatory and gastro-protective properties. Conclusion: Diclofenac potassium-loaded SLMs based on SRMS could be used orally or parenterally under controlled conditions, for once daily administration.
J Microencapsul. 2012 Sep 21;: 22994538
Preliminary studies on the development of IgA-loaded chitosan-dextran sulphate nanoparticles as a potential nasal delivery system for protein antigens.
School of Pharmacy, CHIRI, Western Australia Biomedical Research Institute, Curtin University , GPO Box U1987, Perth, Western Australia 6845 , Australia.
This study describes the development of a biodegradable nanoparticulate system for the intranasal delivery of multiple proteins. Chitosan (CS)-dextran sulphate (DS) nanoparticles were developed and optimised for the incorporation of pertussis toxin (PTX) and a potential targeting ligand (immunoglobulin-A, IgA). In vitro characterization and in vivo uptake studies were performed for the evaluation of developed nanoparticles. The ratio of CS to DS, the order of mixing and pH of nanoparticle suspension were identified as important formulation factors governing the size and zeta potential of nanoparticles. An optimised CS-DS nanoparticle formulation prepared with the CS to DS weight ratio of 3 : 1 was used to load PTX and/or IgA. Entrapment efficiency of >90% was obtained for both. The in vivo uptake of IgA-loaded CS-DS nanoparticles in mice showed a preferential uptake of nanoparticles probably by nasal membranous or microfold cells following intranasal administration. The results of this study indicate the potential application of IgA-loaded CS-DS nanoparticles as a nasal vaccine delivery system.
J Microencapsul. 2012 Sep 19;: 22991962
Centre for Molecular and Structural Biomedicine/Institute for Biotechnology and Bioengineering, Faculty of Sciences and Technology, University of Algarve , Campus de Gambelas, 8005-139 Faro , Portugal.
Tuberculosis remains the leading cause of preventable deaths worldwide and unsuccessful therapy is mainly due to non-compliance with very prolonged treatments, often associated with severe side-effects. Overcoming this problem demands the introduction of drug carriers releasing the antimicrobial agents in a targeted and sustained manner, allowing reduction in frequency and dosing numbers. Nano- and microparticles have taken the forefront of this approach, providing the means for the desired improvement of therapeutic schedules. Natural polymers are strong candidates as matrix-forming materials, usually exhibiting biocompatibility, biodegradability, low cost and some technological advantages as compared with synthetic counterparts. In this review, natural particulate carriers developed for tuberculosis therapy are presented, mainly focusing on the use of polysaccharides and lipids. Their effectiveness is discussed taking into account their composition. Finally, considerations on the general potential of natural materials for this application, as well as key factors still to be addressed, are discussed.
J Microencapsul. 2012 Sep 12;: 22970750
Application of whey protein micro-bead coatings for enhanced strength and probiotic protection during fruit juice storage and gastric incubation.
Teagasc Food Research Centre , Moorepark, Fermoy, Co. Cork , Ireland.
Context: Coated whey protein micro-beads may improve probiotic protection and provide delayed cell-release mechanisms. Objective: Lactobacillus rhamnosus GG was encapsulated in whey protein micro-beads by droplet extrusion with coating via electrostatic deposition: primary-polysaccharide and secondary-whey protein. Materials and methods: Storage studies were performed in cranberry and pomegranate juice (pH 2.4; 28 days; 4 and 25°C) followed by simulated ex vivo porcine gastric (pH 1.6) and intestinal (pH 6.6) digestion. Results and discussion: After storage and simulated gastro-intestinal digestion, free cells, cells suspended in protein and cells encapsulated in alginate micro-beads, illustrated complete probiotic mortality, while coated micro-beads enhanced probiotic viability after juice storage (8.6 ± 0.1 log(10)CFUmL(-1)). Beads also showed significant binding of hydrophobic molecules. Coated micro-beads illustrated high gastric survival (9.5 ± 0.1 log(10)CFUmL(-1)) with 30 min delayed intestinal release relative to non-coated micro-beads. Conclusions: Micro-bead coatings could be applied in delayed cell-release for targeted intestinal probiotic delivery.
J Microencapsul. 2012 ;29 (6):569-75 22913470
Fabrication and characterisation of 2NDPA-loaded poly(lactide-co-glycolide)(PLG) microspheres for explosive safety.
Department of Biology, Biosecurity & Public Health, Los Alamos National Laboratory , Los Alamos, NM 87545 , USA.
We demonstrate the microencapsulation of a double-base (DB) rocket propellant stabiliser, 2-nitrodiphenylamine (2-NDPA), that can potentially increase the shelf life of DB rocket propellants. Poly(lactide-co-glycolide)(PLG) microspheres loaded with 2-NDPA were prepared using the oil-in-water emulsion technique. The microsphere size was found to be inversely related to the mixing rate. It was also found that a higher theoretical loading of 2-NDPA resulted in larger microspheres. In addition, a Rosin Rammler distribution function gave an accurate representation of the microsphere size distribution, and the release rate 2-NDPA from PLG microspheres was found to be size dependent. We show that parameters such as the stirring speed and the percent loading of 2-NDPA can be varied to tailor the release of 2-NDPA from PLG microspheres. In addition, we have shown that temperature has a dramatic effect on the release of 2-NDPA from PLG microcapsules.
J Microencapsul. 2012 Aug 15;: 22894166
Faculté de Pharmacie, Université de Montréal , C.P. 6128, Succursale Centre-ville, Montréal, Québec , Canada H3C 3J7.
Poly(ethylene glycol)/polylactic acid (PEG/PLA) nanoparticles (NPs) containing the hydrophobic antifungal itraconazole (ITZ) were developed to provide a controlled release pattern of ITZ as well as to improve its aqueous dispersibility and hence enhance its antifungal action. Two PEG/PLA copolymers (PEGylated PLA polymers) were used in this study; branched PEGylated polymer in which PEG was grafted on PLA backbone at 7%(mol/mol of lactic acid monomer), PEG7%-g-PLA, and multiblock copolymer of PLA and PEG,(PLA-PEG-PLA)n with nearly similar PEG insertion ratio and similar PEG chain length. ITZ-loaded PLA NPs were also prepared and included in this study as a control. ITZ-NPs were prepared from a 1 : 1 w/w blend of PLA and each PEGylated polymer either PEG7%-g-PLA or (PLA-PEG-PLA)n using an oil-in-water emulsion evaporation method. The NPs morphology, size and size distribution, zeta potential, loading efficiency, release profile and antifungal activity were characterized. All ITZ-NPs were nearly spherical with smooth surface and showed less aggregating tendency with a size range of 185-285 nm. All ITZ-NPs measured nearly neutral zeta potential values close to 0 mV. The % LE of ITZ was ∼94% for PEG7%-g-PLA NPs and ∼83% for (PLA-PEG-PLA)n at 15.3% w/w theoretical loading. PEG/PLA NPs were stable over time regarding size and size distribution and % ITZ loading efficiency (% LE). ITZ release showed an initial burst followed by a gradual release profile for ITZ-NPs over 5 days.(PLA-PEG-PLA)n NPs exhibited faster release rates than PEG7%-g-PLA NPs particularly at the last 2 days. Differential scanning calorimetry and powder X-ray diffractometry data confirmed that ITZ exists in an amorphous state or a solid solution state into the NPs matrix. Fourier transform infrared revealed the possibility of chemical interaction between ITZ and the NPs matrix polymer indicating the successful entrapment of ITZ inside the particles. In haemolysis test, ITZ-NPs caused mild haemolysis over the concentration range (5-20 µg/mL) compared to free ITZ, indicating better safety profile of ITZ-NPs. ITZ-loaded PEG/PLA NPs inhibited fungal growth more efficiently than either free ITZ or ITZ-loaded PLA NPs. Our results suggest that PEG/PLA-ITZ could be used efficiently as a nanocarrier to improve the aqueous dispersibility of ITZ, control its release over time and, thereby, enhance its antifungal efficacy.
J Microencapsul. 2012 Aug 15;: 22894165
Research Center for Nanotechnology, Changchun University of Science and Technology , 7186 Weixing Road, Changchun 130022, Jilin Province , P.R. China.
This article used MCM-41 as a carrier for the assembly of propranolol hydrochloride by the impregnation method. By means of chemical analysis, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy and low-temperature N(2) adsorption-desorption at 77 K, the characterization was made for the prepared materials. The propranolol hydrochloride guest assembly capacity was 316.20 ± 0.31 mg/g (drug/MCM-41). Powder XRD test results indicated that during the process of incorporation, the frameworks of the MCM-41 were not destroyed and the crystalline degrees of the host-guest nanocomposite materials prepared still remained highly ordered. Characterization by SEM and TEM showed that the composite material presented spherical particle and the average particle size of composite material was 186 nm. FT-IR spectra showed that the MCM-41 framework existed well in the (MCM-41)-propranolol hydrochloride composite. Low-temperature nitrogen adsorption-desorption results at 77 K showed that the guest partially occupied the channels of the molecular sieves. Results of the release of the prepared composite drug in simulated body fluid indicated that the drug can release up to 32 h and its maximum released amount was 99.20 ± 0.11%. In the simulated gastric juice release pattern of drug, the maximum time for the drug release was discovered to be 6 h and the maximum cumulative released amount of propranolol hydrochloride was 45.13 ± 0.23%. The drug sustained-release time was 10 h in simulated intestinal fluid and the maximum cumulative released amount was 62.05 ± 0.13%. The prepared MCM-41 is a well-controlled drug delivery carrier.
J Microencapsul. 2012 Aug 15;: 22894164
In situ absorption and relative bioavailability studies of zaleplon loaded self-nanoemulsifying powders.
Karthik Y Janga, Raju Jukanti, Sharath Sunkavalli, Ashok Velpula, Suresh Bandari, Prabhakar Kandadi, Prabhakar Reddy Veerareddy
Department of Pharmaceutics, St. Peter's Institute of Pharmaceutical Sciences , Hanamkonda, Warangal, Andhra Pradesh , India.
Self-nanoemulsifying drug delivery systems (SNEDDSs) offer potential as suitable carriers for improved oral delivery of poorly soluble and low bioavailable drugs. To derive self-nanoemulsifying powders (SNEPs), the optimized Z-SNEDDS formulation was adsorbed onto different carriers and based on micromeritics the formulation loaded onto neusilin US2 (SNEP-N) was selected for further characterization. The solid-state characterization (scanning electron microscopy, differential scanning calorimetry and powder X-ray diffraction) studies unravel the transformation of native crystalline state to amorphous and/or molecular state. The higher predictive effective permeability coefficient and fraction absorbed in humans extrapolated from in situ single-pass intestinal absorption study data in rats provide an insight on the potential of SNEPs for augment in absorption across gastrointestinal barrier. Overall a 3.5-fold enhancement in the extent of absorption of zaleplon from SNEP-N formulation proves the feasibility of SNEPs formulation for improved oral delivery of zaleplon.
J Microencapsul. 2012 Aug 3;: 22861176
Long-acting formulation of a new muscarinic receptor antagonist for the treatment of overactive bladder.
Lesheng Teng, Chaojun Jiang, Fengying Sun, Chunmei Li, Lirong Teng, Qingfan Meng, Robert J Lee, Youxin Li
College of Life Science, Jilin University , Changchun 130012 , China.
A new muscarinic receptor antagonist, 5-hydroxymethyl tolterodine (5-HMT), was successfully encapsulated into PLGA microspheres. With an increase of PLGA concentration from 15% to 40%, encapsulation efficiency of 5-HMT increased from 55.39% to 76.32%, and the particle size of microsphere increased from 34.33 to 70.48 µm. Increasing the homogenisation speed from 850 to 2300 rpm, the particle size was reduced about 65%.The in vitro and in vivo studies in beagle dogs show that the release profile of 5-HMT-loaded microspheres (5-HMT MS) prepared with 503H is characterised by a low initial burst followed by slow release that lasted for 2 weeks. A C(max) of 1.617 ± 0.392 ng/mL was found on the sixth day. When evaluated for inhibition of the carbachol-induced contraction of rat urinary bladder, 5-HMT MS showed a much longer and more potent effect than tolterodine tablets. The mean urination time of the rats in the 5-HMT MS group was significantly decreased (p < 0.05 or p < 0.01) to less than 2 weeks.