SciCombinator

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Concept: Hypromellose

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The present investigation was carried out to formulate and optimize the bioerodable insert of Azithromycin in order to prolong the release time and improve the ocular availability in ophthalmic infections. A modified solvent casting method was used for the preparation of azithromycin insert in which hydroxyl propyl methyl cellulose (HPMC) and Eudragit RL100 were used as drug reservoir and rate controlling membrane respectively. Thereafter the, formulations were evaluated for the uniformity of thickness and weight, surface pH, folding endurance, percentage moisture loss, percentage moisture absorption, drug content, in-vitro release, kinetics studies (zero order, first order, Higuchi and Korsmeyer - Peppas model) and stability studies. The Formulation H8 (amongst the range of H1-H10) ,comprising of 1.5% HPMC and 3% Eudragit RL100 ,was found to be optimized formulation on the basis of uniformity of thickness (0.26 ± 0.004 mm) and weight (24.9 ± 0.27 mg), surface pH (7.1 ± 0.063), folding endurance (18.3 ± 0.81), percentage moisture loss (7.49 ± 0.30%), percentage moisture absorption (5.7%), drug content (1.98 mg ), in-vitro release (99%) , stability studies (Shelf life- 346 days) and better ocular tolerability. The formulation H8 showed a steady and controlled release of the drug over a 12 hour period with non-Fickian diffusion release mechanism, compared to a normal release period of 2-3 hours. The optimized insert showed promising results and can be used to treat a wide range of ocular infections.

Concepts: Pharmaceutical formulation, Hypromellose, Shelf life, Formulation, Control, E number, Methyl cellulose, Cellulose

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The objective of this study was to investigate the effect of polymeric microcarriers on the in-vivo intranasal uptake of an anti-migraine drug for brain targeting. Mucoadhesive powder formulations consisted of antimigraine drug, zolmitriptan, and chitosans (various molecular weights and types) or hydroxypropyl methylcellulose (HPMC). Their suitability for nasal administration was evaluated by in-vitro and ex-vivo mucoadhesion and permeation tests. The formulations based on chitosan glutamate (CG) or HPMC were tested in-vivo because they showed good mucoadhesive properties and altered the permeation rate of the drug. The in-vivo results from intravenous infusion and nasal aqueous suspension of the drug or nasal particulate powders were compared. The plasmatic AUC values obtained within 8 h following intravenous administration appeared about three times higher than those obtained by nasal administration, independent of the formulations. Zolmitriptan concentrations in the cerebrospinal fluid obtained from nasal and intravenous administrations were respectively 30 and 90 times lower than the concentrations of the drug in the blood. Thus, nasal administration potentiated the central zolmitriptan activity allowing a reduction of the drug peripheral levels, with respect to the intravenous administration. Among nasally administered formulations, CG microparticles showed the highest efficacy in promoting the central uptake of zolmitriptan within 1 h.

Concepts: Psychoactive drug, Hypromellose, Methyl cellulose, Route of administration, Cerebrospinal fluid, Bolus, Intravenous therapy, Chemistry

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This study aimed to compare the dissolution and the intestinal absorption of tacrolimus in self-microemulsifying drug delivery system (SMEDDS) and solid dispersion (SD). Poloxamer 188 SD was prepared by the combination of the solvent evaporation method and the freeze drying method. Hydroxypropyl methylcellulose (HPMC) SD was prepared by the solvent evaporation method combined with the vacuum drying method. The formation of SD was confirmed by SEM images which showed new solid phases. The SMEDDS was composed of oil (Labrafil M1944 CS 28%), surfactant (Cremophor EL 48%) and co-surfactant (Transcutol P 24%). The self microemulsion formed by the SMEDDS upon aqueous media had spherical droplets with a hydrodynamic size of 46.0±3.2nm. The dissolution of tacrolimus from SD and SMEDDS was performed in sink and non-sink conditions with various pH. As revealed by the DSC and FT-IR, the tacrolimus was molecularly or amorphously dispersed in the SMEDDS and SD. The in vivo intestinal absorption study in rats showed that both SMEDDS and SD improved the absorption of tacrolimus over the raw tacrolimus while the SMEDDS exhibited lower absorption rate constant (Ka) and apparent permeability coefficients (Papp) than the SD. The self-prepared SD with poloxamer 188 or HPMC had comparable intestinal absorption as compared with Prograf®. The tacrolimus-loaded SMEDDS and SD would be further compared by in vivo pharmacokinetic study.

Concepts: Food preservation, Freeze drying, Emulsion, Hypromellose, Pharmacology, Methyl cellulose, Cellulose, Liquid

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This study presents a design that lipophilic drug was encapsulated within dissolving microneedles (DMNs) for sustained-release delivery over one week. Etonogestrel (ENG), the progestogen used in hormonal contraceptives, was loaded in two-layered DMNs in form of microcrystal particles (MP). In vitro release study indicated that ENG in form of MP could sustain drug release compared to non-crystal form. Hydroxypropyl methylcellulose (HPMC) and polyvinyl alcohol (PVA) was used to prepare the fast dissolving needle-tips and flexible back layer, respectively. The mechanical strength of microneedles was not affected even with the drug loading efficiency of 50.0% in needle-tips. The penetration depth of DMNs in skin, observed by confocal laser scanning microscopy (CLSM), was approximately 280 μm. The tips of DMNs could be dissolved in rat skin within 1 hour with drug delivery efficiency of 63.8 ±2.0%. Pharmacokinetics study of DMNs treatment in rats showed that the plasma levels of ENG were a dose-dependent profile and much steadier than intradermal injection. There was no statistical difference between bioavailability of ENG treated by DMNs or intradermal injection (p > 0.05). Therefore, the novel DMNs loaded with drug MP provided a potential minimally invasive route for intradermal sustained delivery of lipophilic drug.

Concepts: Implanon, Hypromellose, Hormonal contraception, Methyl cellulose, Pharmaceutical drug, Polyvinyl acetate, Polyvinyl alcohol, Pharmacology

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Concomitant ingestion of alcohol and medications can greatly affect drug plasma concentrations as dose dumping or failure may occur as a result of the fact that formulation excipients may not always be resistant to alcohol. In this study, a natural polysaccharide (Sesamum radiatum gum) (SG) was extracted, characterized and used to formulate sustained release theophylline compacts to study the effect of varying alcohol concentrations (v/v) in dissolution media on drug release from these compacts. X-ray powder diffraction showed that the extracted gum was amorphous in nature with the powder having excellent compaction properties as observed with its compact being significantly harder than those prepared with pure hydroxypropyl methyl cellulose (HPMC) K4M. X-ray microtomography showed that the compacts produced were homogenous in nature, however, swelling studies showed failure of the compacts at the highest concentration of absolute ethanol used (40% v/v). Dissolution studies showed similarity at all levels of alcohol tested (f2 = 57-91) in simulated gastric (0.1 N HCl, pH 1.2) and intestinal fluids (phosphate buffer, pH 6.8) for the HPMC compacts whereas dissimilarity only occurred for the SG compacts at the highest alcohol concentration in both media (f2 = 35). The suitability of SG as a matrix former that can resist alcoholic effects therefore makes it suitable as an alternative polymer with wider applications for drug delivery.

Concepts: Hypromellose, Methyl cellulose, Ethanol, Alcohol, Diffraction, E number, Excipients, Cellulose

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Paliperidone (PLPD) is approved for treatment and management of schizophrenia. The current study demonstrates the potential of in situ gel of PLPD for nasal delivery. The permeation of drug through sheep nasal mucosa was analyzed since the nose-to-brain pathway has been indicated for delivering drugs to the brain. The carbopol 934 (CP)- and hydroxypropyl methyl cellulose K4M (HPMC)-based in situ gels containing 0.2% CP and 0.4% w/v HPMC were optimized using experimental design software. The use of hydroxypropyl-β-cyclodextrin (HP-β-CD) in nasal permeation of drug was investigated. Transmucosal permeation of PLPD was examined using sheep nasal mucosa. The in situ gels of PLPD exhibited satisfactory mucoadhesion and showed sustained drug release. The mucocilliary toxicity and histopathological examination confirmed that the nasal mucosa architecture remains unaffected after treatment with PLPD in situ gel. The formulation containing HP-β-CD complex of PLPD exhibited higher rate of drug permeation through sheep nasal mucosa revealing the role of HP-β-CD as nasal absorption enhancer. Thus, CP- and HPMC-based pH-triggered in situ gel containing HP-β-CD-drug inclusion complex demonstrates a novel nasal delivery of PLPD.

Concepts: Gel, Excipients, Psychoactive drug, Mucus, Hypromellose, Methyl cellulose, E number, Cellulose

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To assess the effect of hydroxypropyl methylcellulose (HPMC) 2% to prevent dry eye during phacoemulsification in senile and diabetic patients.

Concepts: Cellulose, E number, Methyl cellulose, Hypromellose

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Effects of sodium carboxymethyl cellulose (CMC) and hydroxypropyl methyl cellulose (HPMC) on the pasting, viscoelastic, and morphological properties of rice starch gel were studied. The addition of CMC increased the peak and trough viscosities, while decreased the final and setback viscosities of rice starch. The peak and trough viscosities of rice starch gel were only little affected by the addition of HPMC. The dynamic viscoelastic result showed that the addition of CMC significantly increased the values of storage modulus (G') and loss modulus (G″), while reduced the value of tanδ as compared to the control sample. Only a small increase in values of G' and G″ was observed in the case of HPMC. The rice starch gel with CMC addition exhibited higher resistances to the stress and produced a stronger gel network. The creep recovery data were well fitted by a four-element Burger’s model. Furthermore, the morphological characteristics were in agreement with the finding of rheological results. It was concluded that the addition of CMC and HPMC modified the rheology of rice starch gel in different ways and interacted under different models based on their molecular structures.

Concepts: Edible thickening agents, Hypromellose, Excipients, Starch, Methyl cellulose, Carboxymethyl cellulose, E number, Cellulose

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The need to combat poor water solubility has increased interest in supersaturating drug delivery systems. In this study, amorphous mesoporous magnesium carbonate (MMC) was used as a drug carrier to achieve supersaturation of tolfenamic acid and rimonabant, two drug compounds with low aqueous solubility. The potential synergy between MMC and hydroxypropyl methylcellulose (HPMC), a polymer commonly included as a precipitation inhibitor in drug delivery systems, was explored with the aim of extending the time that high supersaturation levels were maintained. Release was studied under physiological conditions using USP-2 dissolution baths. A new small-scale method was developed to enable measurement of the initial drug release occurring when the MMC is immersed in the water phase. It was shown that MMC and HPMC together resulted in significant supersaturation and that the polymer enabled both the achievement of a higher API concentration and extension of the supersaturation period. The new small-scale release method showed that the release was linearly increasing with the dose and that similar release rates were observed for the two model compounds. It was hence concluded that the MMC release was diffusion limited for the compounds explored.

Concepts: Pharmacology, Hypromellose, Precipitation, Drugs, Methyl cellulose, Solvation, Phase, Solubility

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Dairy desserts are popular traditional products but because of their high calorie or fat content, they can be unsuitable for people who have certain dietary requirements. The aim of this study was to design panna cottas with similar organoleptic and textural properties to the traditional ones but with a lower fat content, by replacing part of the cream with new emulsions prepared with hydrocolloids (cellulose ethers), namely methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC).

Concepts: Nutrition, Emulsion, Excipients, Hypromellose, Milk, Methyl cellulose, E number, Cellulose