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Fulltext Insulin-Loaded Barium Salt Particles Facilitate Oral Delivery of Insulin in Diabetic Rats

Zaman R, Karim ME, Othman I, Zaini A, Chowdhury EH

Pharmaceutics, 2020 Jul 29;12(8).
PMID: 32751231 DOI: 10.3390/pharmaceutics12080710

Oral delivery is considered as the most preferred and yet most challenging mode of drug administration; especially a fragile and sensitive peptide like insulin that shows extremely low bioavailability through the gastro-intestinal (GIT) route. To address this problem, we have designed a novel drug delivery system (DDS) using precipitation-induced Barium (Ba) salt particles. The DDS can load insulin molecules and transport them through the GIT route. There were several in vitro simulation tests carried out to prove the efficiency of Ba salt particles as oral delivery candidates. All three Ba salt particles (BaSO4, BaSO3, and BaCO3) showed very good loading of insulin (>70% in all formulations) and a degree of resistance throughout a wide range of pHs from basic to acidic conditions when assessed by spectrophotometry. Particles and insulin-associated particles were morphologically assessed and characterized using FE-SEM and FT-IR. A set of tests were designed and carried out with mucin to predict whether the particles are potentially capable of overcoming one of the barriers for crossing intestinal epithelium. The mucin binding experiment demonstrated 60-100% of mucin adhesion to the three different particles. FT-IR identifies the characteristic peaks for mucin protein, particles, and particle-mucin complex re-confirming mucin adhesion to the particles. Finally, the effectiveness of nano-insulin was tested on streptozotocin (STZ) induced diabetic rats. A short acting human insulin analog, insulin aspart, was loaded into Ba salt particles at a dose of 100 IU/Kg prior to oral administration. Among the three formulations, insulin aspart-loaded BaSO4 and BaCO3 particles dramatically reduced the existing hyperglycemia. BaSO4 with loaded Insulin showed an onset of glucose-lowering action within 1 hr, with blood glucose level measured significantly lower compared to the 2nd and 3rd h (p < 0.05). Insulin-loaded BaCO3 particles showed a significant decrease in blood glucose level at 1-2 h, although the glucose level started to show a slight rise at 3rd h and by 4th h, it was back to baseline level. However, although BaSO3 particles with loaded insulin showed a trend of reduction in blood glucose level, the reduction was not found to be significant (p < 0.05) at any point in time. Therefore, oral formulations of insulin/BaSO4 and insulin/BaCO3 particles were observed as effective as native insulin aspart subcutaneous formulation in terms of onset and duration of action. Further investigation will be needed to reveal bioavailability and mechanism of action of this novel Nano-Insulin formulations.

Matched MeSH terms: Biological Availability
Diosgenin, a steroidal saponin, and its analogs: Effective therapies against different chronic diseases

Parama D, Boruah M, Yachna K, Rana V, Banik K, Harsha C, et al.

Life Sci, 2020 Nov 01;260:118182.
PMID: 32781063 DOI: 10.1016/j.lfs.2020.118182

BACKGROUND: Chronic diseases are a major cause of mortality worldwide, and despite the recent development in treatment modalities, synthetic drugs have continued to show toxic side effects and development of chemoresistance, thereby limiting their application. The use of phytochemicals has gained attention as they show minimal side effects. Diosgenin is one such phytochemical which has gained importance for its efficacy against the life-threatening diseases, such as cardiovascular diseases, cancer, nervous system disorders, asthma, arthritis, diabetes, and many more.
AIM: To evaluate the literature available on the potential of diosgenin and its analogs in modulating different molecular targets leading to the prevention and treatment of chronic diseases.
METHOD: A detailed literature search has been carried out on PubMed for gathering information related to the sources, biosynthesis, physicochemical properties, biological activities, pharmacokinetics, bioavailability and toxicity of diosgenin and its analogs.
KEY FINDINGS: The literature search resulted in many in vitro, in vivo and clinical trials that reported the efficacy of diosgenin and its analogs in modulating important molecular targets and signaling pathways such as PI3K/AKT/mTOR, JAK/STAT, NF-κB, MAPK, etc., which play a crucial role in the development of most of the diseases. Reports have also revealed the safety of the compound and the adaptation of nanotechnological approaches for enhancing its bioavailability and pharmacokinetic properties.
SIGNIFICANCE: Thus, the review summarizes the efficacy of diosgenin and its analogs for developing as a potent drug against several chronic diseases.

Matched MeSH terms: Biological Availability
Fulltext Gliclazide loaded PLGA-HPMC second generation nanocrystals for oral delivery: design, development and in vitro performance characterization

Krishnamoorthy R., Bibhu Prasad Panda, Shivashekaregowda N. K. H., Low B. S., Bhattamisra S. K.

Malaysian Journal of Medicine and Health Sciences, 2019;15(102):44-44.
MyJurnal

Introduction: Second generation functionalized nanocrystal is the advancement of nanocrystal technology with great potential to accommodate BCS (Biopharmaceutical Classification System) class II drugs to meet their formulation and drug delivery challenges. Gliclazide is a BCS class II drug used in the treatment of type 2 diabetes, shows poor water solubility and low rate of dissolution, leads to poor and variable oral bioavailability. The second generation poly(D,L-lactide-co-glycolide) (PLGA) Hydroxypropyl methylcellulose (HPMC) based functionalized nanocrystals of gliclazide were prepared by a combination method of emulsion diffusion-high pressure homogenization-solvent evaporation. Methods: Gliclazide second generation nanocrystals were fabricated with taguchi orthogonal experimental design in combination of step up and top down nanoformulation strategies using drug-polymer (PLGA) ratio at 1:0.5, 1:0.75, 1:1 with HPMC(0.5, 0.75, 1% w/v) as stabilizer. The formulated gliclazide PLGA-HPMC nanocrystals were investigated on particle size, polydispersity index, zeta potential, solubility study, drug entrapment efficiency, in vitro drug release, and surface morphology and compatibility studies. The gliclazide PLGA nanocrystals formulation was prepared with Drug : PLGA at 1: 1 ratio with concentrations 0.75% w/v HPMC at 5 homogenization cycles with 1000bar produce optimized gliclazide nanocrystals. Results: The optimized MSGNC8 formulation
showed particle size of 239.9 nm, entrapment efficiency 98.62%, and drug release of 43.75%, 82.12% and 98.08% at 3hrs, 24hrs, and 48hrs compared to pure gliclazide % drug release of 28.73%, 67.51% and 78.41% at 3hrs, 24hrs, 48hrs respectively. The solubility study of optimized formulation shows eight folds increased in saturation solubility compared to pure drug. Scanning electron microscopy (SEM) analysis of the gliclazide nanocrystals revealed that
gliclazide retained its crystal morphology in polymeric nanocrystals. Further, fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) studies on gliclazide PLGA-HPMC nanocrystals emphasize drug and excipient compatibility in development of gliclazide nanocrystals. Conclusion: The potential outcomes of research findings emphasize that the developed gliclazide second-generation nanocrystals, which resulted in increase in drug solubility and rate of dissolution with delayed modified release, can be explored in delivery of gliclazide for type 2 diabetes management.

Matched MeSH terms: Biological Availability
Fulltext Mechanistic Approaches of Internalization, Subcellular Trafficking, and Cytotoxicity of Nanoparticles for Targeting the Small Intestine

Madni A, Rehman S, Sultan H, Khan MM, Ahmad F, Raza MR, et al.

AAPS PharmSciTech, 2020 Nov 22;22(1):3.
PMID: 33221968 DOI: 10.1208/s12249-020-01873-z

Targeting the small intestine employing nanotechnology has proved to be a more effective way for site-specific drug delivery. The drug targeting to the small intestine can be achieved via nanoparticles for its optimum bioavailability within the systemic circulation. The small intestine is a remarkable candidate for localized drug delivery. The intestine has its unique properties. It has a less harsh environment than the stomach, provides comparatively more retention time, and possesses a greater surface area than other parts of the gastrointestinal tract. This review focuses on elaborating the intestinal barriers and approaches to overcome these barriers for internalizing nanoparticles and adopting different cellular trafficking pathways. We have discussed various factors that contribute to nanocarriers' cellular uptake, including their surface chemistry, surface morphology, and functionalization of nanoparticles. Furthermore, the fate of nanoparticles after their uptake at cellular and subcellular levels is also briefly explained. Finally, we have delineated the strategies that are adopted to determine the cytotoxicity of nanoparticles.

Matched MeSH terms: Biological Availability
Fulltext Lyophilized Amorphous Dispersion of Telmisartan in a Combined Carrier-Alkalizer System: Formulation Development and In Vivo Study

Al-Japairai KAS, Alkhalidi HM, Mahmood S, Almurisi SH, Doolaanea AA, Al-Sindi TA, et al.

ACS Omega, 2020 Dec 22;5(50):32466-32480.
PMID: 33376884 DOI: 10.1021/acsomega.0c04588

Telmisartan suffers from low oral bioavailability due to its poor water solubility. The research work presents a formulation of solid dispersed (SD) telmisartan formulation as a ternary mixture of a drug, a polymeric carrier (poly(vinylpyrrolidone) (PVP) K30), and an alkalizer (Na2CO3). The preparation method, which was lyophilization of an aqueous solution containing the ingredients, was free from any organic solvent. The developed SD formulations resulted in a significant improvement in in vitro dissolution (>90% drug dissolution in 15 min) compared to pure telmisartan. Solid-state characterization by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) studies indicated the conversion of crystalline telmisartan into an amorphous form. Fourier transform infrared (FTIR) spectroscopy revealed the drug-polymer interaction that was responsible for reducing the chances of recrystallization. A short-term stability study showed that selected SD formulations were stable in terms of in vitro dissolution and retained their amorphous structure in ambient and accelerated conditions over 2 months. Selected formulations (drug/PVP K30/Na2CO3 as 1:1:2 or 1:2:2 weight ratio) resulted in >2.48 times relative oral bioavailability compared to marketed formulations. It was considered that the incorporation of an alkalizer and a hydrophilic polymer, and amorphization of telmisartan by lyophilization, could enhance in vitro dissolution and improve oral bioavailability.

Matched MeSH terms: Biological Availability
Fulltext Synthesis and Optimization of Mesoporous Silica Nanoparticles for Ruthenium Polypyridyl Drug Delivery

Harun SN, Ahmad H, Lim HN, Chia SL, Gill MR

Pharmaceutics, 2021 Jan 24;13(2).
PMID: 33498795 DOI: 10.3390/pharmaceutics13020150

The ruthenium polypyridyl complex [Ru(dppz)2PIP]2+ (dppz: dipyridophenazine, PIP: (2-(phenyl)-imidazo[4,5-f ][1,10]phenanthroline), or Ru-PIP, is a potential anticancer drug that acts by inhibiting DNA replication. Due to the poor dissolution of Ru-PIP in aqueous media, a drug delivery agent would be a useful approach to overcome its limited bioavailability. Mesoporous silica nanoparticles (MSNs) were synthesized via a co-condensation method by using a phenanthrolinium salt with a 16 carbon length chain (Phen-C16) as the template. Optimization of the synthesis conditions by Box-Behnken design (BBD) generated MSNs with high surface area response at 833.9 m2g-1. Ru-PIP was effectively entrapped in MSNs at 18.84%. Drug release profile analysis showed that Ru-PIP is gradually released, with a cumulative release percentage of approximately 50% at 72 h. The release kinetic profile implied that Ru-PIP was released from MSN by diffusion. The in vitro cytotoxicity of Ru-PIP, both free and MSN-encapsulated, was studied in Hela, A549, and T24 cancer cell lines. While treatment of Ru-PIP alone is moderately cytotoxic, encapsulated Ru-PIP exerted significant cytotoxicity upon all the cell lines, with half maximal inhibitory concentration (IC50) values determined by MTT (([3-(4,5-dimethylthiazol-2-yl)-2,5-dephenyltetrazolium bromide]) assay at 48 h exposure substantially decreasing from >30 µM to <10 µM as a result of MSN encapsulation. The mechanistic potential of cytotoxicity on cell cycle distribution showed an increase in G1/S phase populations in all three cell lines. The findings indicate that MSN is an ideal drug delivery agent, as it is able to sustainably release Ru-PIP by diffusion in a prolonged treatment period.

Matched MeSH terms: Biological Availability
Fulltext Honey and its nutritional and anti-inflammatory value

Ranneh Y, Akim AM, Hamid HA, Khazaai H, Fadel A, Zakaria ZA, et al.

BMC Complement Med Ther, 2021 Jan 14;21(1):30.
PMID: 33441127 DOI: 10.1186/s12906-020-03170-5

Inflammation is the main key role in developing chronic diseases including cancer, cardiovascular diseases, diabetes, arthritis, and neurodegenerative diseases which possess a huge challenge for treatment. With massively compelling evidence of the role played by nutritional modulation in preventing inflammation-related diseases, there is a growing interest into the search for natural functional foods with therapeutic and preventive actions. Honey, a nutritional healthy product, is produced mainly by two types of bees: honeybee and stingless bee. Since both types of honey possess distinctive phenolic and flavonoid compounds, there is recently an intensive interest in their biological and clinical actions against inflammation-mediated chronic diseases. This review shed the light specifically on the bioavailability and bioaccessibility of honey polyphenols and highlight their roles in targeting inflammatory pathways in gastrointestinal tract disorders, edema, cancer, metabolic and cardiovascular diseases and gut microbiota.

Matched MeSH terms: Biological Availability
Fulltext Optimisation of the production of fish gelatine nanoparticles as a carrier for sunflower-derived biopeptide

Akbar, I., Jaswir, I., Jamal, P.

International Food Research Journal, 2020;27(1):171-181.
MyJurnal

Gelatine obtained from fish skin has become a potential source of preparing nanoparticles and
encapsulation of bioactive compounds. Within these fish skin, gelatine nanoparticles show
potent benefits for application in pharmaceutical and cosmetic industry. The encapsulated
bioactive ingredients within nanoparticles have improved bioavailability, delivery properties,
and solubility of the nutraceuticals within the human body and blood stream. Many of such
bioactive peptides (biopeptides) are potent antioxidants; and as oxidative stress is the main
cause of the onset of various chronic diseases, encapsulation of antioxidant biopeptides within
fish gelatine nanoparticles could be a potential remedy to prevent or delay the onset of such
diseases and for better health prospects. The purpose of the present work was to prepare a
simple, safe, and reproducible novel food delivery nanoparticle system encapsulating a desirable antioxidant biopeptide. An optimisation study was conducted to produce a desirable size
of gelatine nanoparticles which showed a higher encapsulation efficiency of an antioxidant
biopeptide. Sunflower biopeptide was chosen as the antioxidant biopeptide, as the activity of
this protein hydrolysate is quite high at DPPH of 89% and FRAP assay of 968 µm/L. Tilapia
fish was used as gelatine source at an average yield of the process at 10% wt/wt. Effects of
parameters such as pH, biopeptide concentration, and cross-linking agent ‘glutaraldehyde’ on
the size, stability, and encapsulation efficiency on the nanoparticles were studied. The average
diameter of the biopeptide loaded gelatine nanoparticle was between 228.3 and 1,305 nm.
Encapsulation efficiency was 76% at an optimal pH of 2, glutaraldehyde concentration of 2
mL, and biopeptide concentration of 0.1 mg/mL exhibited DPPH at 92% and FRAP assay of
978 µm/L. To understand the absorption of sunflower biopeptide in stomach, blood stream,
and biopeptide release of the gelatine nanoparticles, biopeptide loaded gelatine nanoparticles
were subjected to simulated gastrointestinal conditions mimicking human stomach and
intestine; and showed peptide release of 0.1464 and 0.277 mg/mL upon pepsin and pancreatin
digestion, respectively.

Matched MeSH terms: Biological Availability
Simple high-performance liquid chromatographic method for the determination of acyclovir in human plasma using fluorescence detection

Peh KK, Yuen KH

J Chromatogr B Biomed Sci Appl, 1997 May 23;693(1):241-4.
PMID: 9200543

A simple high-performance liquid chromatographic method using fluorescence detection was developed for the determination of acyclovir in human plasma. The method entailed direct injection of the plasma sample after deproteination. It is both specific and sensitive with a detection limit of 30 ng/ml at a signal-to-noise ratio of 3:1, and is thus suitable for use in pharmacokinetic studies of acyclovir. The method had a mean absolute recovery of 96%, while the within-day and between-day coefficients of variation and percentages error were all less than 8%. The calibration curve was linear over a concentration range of 62.5-4000 ng/ml.

Matched MeSH terms: Biological Availability
Improved oral bioavailability of artemisinin through inclusion complexation with beta- and gamma-cyclodextrins

Wong JW, Yuen KH

Int J Pharm, 2001 Oct 04;227(1-2):177-85.
PMID: 11564552

The bioavailability of beta- and gamma-cyclodextrin artemisinin complexes was evaluated in comparison with a normal commercially available preparation, Artemisinin 250. Twelve healthy male volunteers participated in the study conducted according to a three-way crossover design. The bioavailability was compared using the parameters, total area under the plasma level-time curve (AUC(0-infinity)), peak plasma concentration (C(max)), and time to reach peak plasma concentration (T(max)). A statistically significant difference was observed between the values of the complexes and Artemisinin 250 for the three parameters. However, no statistically significant difference was observed between the values of the beta- and gamma-cyclodextrin complexes. Moreover, the 90% confidence interval for the ratio of the AUC(0-infinity) values of the beta-cyclodextrin complex over those of Artemisinin 250 was estimated to be between 1.51-2.04, while that of C(max) was between 1.73-2.93. For the gamma-cyclodextrin complex, the respective intervals were 1.30-1.76 and 1.43-2.43. These findings indicated that the beta- and gamma-cyclodextrin complexes had a much higher rate and extent of bioavailability compared to Artemisinin 250. In addition, the absorption of artemisinin was observed to be poor and negligible when the preparations started to arrive in the colon. This could be attributed to poor dissolution of artemisinin in the semi-solid faecal matter in the lower part of the gastrointestinal tract.

Matched MeSH terms: Biological Availability
Influence of route of administration on the absorption and disposition of alpha-, gamma- and delta-tocotrienols in rats

Yap SP, Yuen KH, Lim AB

J Pharm Pharmacol, 2003 Jan;55(1):53-8.
PMID: 12625867

A study was conducted to evaluate the bioavailability of alpha-, gamma- and delta-tocotrienols administered via oral, intravenous, intramuscular and intraperitoneal routes in rats. Three separate experiments, each conducted according to a two-way crossover design, were carried out to compare intravenous and oral, intramuscular and oral, and intraperitoneal and oral administration. Oral absorption of all three tocotrienols was found to be incomplete. Of the three tocotrienols, alpha-tocotrienol had the highest oral bioavailability, at about 27.7+/-9.2%, compared with gamma- and delta-tocotrienols, which had values of 9.1+/-2.4% and 8.5+/-3.5%, respectively. Such biodiscrimination was also observed in their total clearance rates (estimated from the intravenous data). alpha-Tocotrienol showed the lowest clearance rate at about 0.16 L kg(-1) h(-1), whereas that of delta- and gamma-tocotrienols was quite similar, with values of 0.24 and 0.23 L kg(-1) h(-1), respectively. Interestingly, all three tocotrienols were found to be negligibly absorbed when administered intraperitoneally and intramuscularly. Thus, these two routes of administration should be avoided when evaluating the biological activities of the tocotrienols in whole animal experiments.

Matched MeSH terms: Biological Availability
Improved bioavailability of vitamin E with a self emulsifying formulation

Julianto T, Yuen KH, Noor AM

Int J Pharm, 2000 Apr 25;200(1):53-7.
PMID: 10845685

A single dose study was conducted to evaluate the bioavailability of a novel self-emulsifying vitamin E preparation, in comparison with that of a commercial product, Natopherol, available as soft gelatin capsules under fasted condition. The self-emulsifying preparation achieved a faster rate and higher extent of absorption. A statistically significant difference was observed between the values of the two preparations in the parameters AUC, Cmax and Tmax. Moreover, the 90% confidence interval of the logarithmic transformed AUC values of the self-emulsifying preparation over those of the soft gelatin capsule product was found to be between 2.1 and 4.1, suggesting an increase in bioavailability of between 210 and 410%. As for Cmax, the 90% confidence interval was between 2.1 and 3.0. However, no statistically significant difference was observed between the t(1/2) values estimated from the plasma concentration versus time data of the two preparations. The values are also comparable to those reported in the literature.

Matched MeSH terms: Biological Availability
Pharmacokinetics and bioavailability of alpha-, gamma- and delta-tocotrienols under different food status

Yap SP, Yuen KH, Wong JW

J Pharm Pharmacol, 2001 Jan;53(1):67-71.
PMID: 11206194

We have investigated the pharmacokinetics and bioavailability of alpha-, gamma- and delta-tocotrienols under fed and fasted conditions in eight healthy volunteers. The volunteers were administered a single oral dose of mixed tocotrienols (300 mg) under fed or fasted conditions. The bioavailability of tocotrienols under the two conditions was compared using the parameters peak plasma concentration (Cmax), time to reach peak plasma concentration (Tmax) and total area under the plasma concentration-time curve (AUC(o-infinity)). A statistically significant difference was observed between the fed and fasted logarithmic transformed values of Cmax (P < 0.01) and AUC(0-infinity) (P < 0.01) for all three tocotrienols. In addition, the 90% confidence intervals for the ratio of the logarithmic transformed AUC(0-infinity) values of alpha-, gamma- and delta-tocotrienols under the fed state over those of the fasted state were found to lie between 2.24-3.40, 2.05-4.09 and 1.59-3.81, respectively, while those of the Cmax were between 2.28-4.39, 2.31-5.87 and 1.52-4.05, respectively. However, no statistically significant difference was observed between the fed and fasted Tmax values of the three homologues. The mean apparent elimination half-life (t(1/2)) of alpha-, gamma- and delta-tocotrienols was estimated to be 4.4, 4.3 and 2.3 h, respectively, being between 4.5- to 8.7-fold shorter than that reported for alpha-tocopherol. No statistically significant difference was observed between the fed and fasted t(1/2) values. The mean apparent volume of distribution (Vd/f) values under the fed state were significantly smaller than those of the fasted state, which could be attributed to increased absorption of the tocotrienols in the fed state.

Matched MeSH terms: Biological Availability
Simple high-performance liquid chromatographic method for the determination of metformin in human plasma

Kah Hay Yuen, Kok Khiang Peh

J Chromatogr B Biomed Sci Appl, 1998 Jun 12;710(1-2):243-6.
PMID: 9686895

A simple high-performance liquid chromatographic method using ultraviolet detection was developed for the determination of metformin in human plasma. The method entailed direct injection of the plasma sample after deproteination using perchloric acid. The mobile phase comprised 0.01 M potassium dihydrogen orthophosphate (pH 3.5) and acetonitrile (60:40, v/v). Analyses were run at a flow-rate of 1.0 ml/min with the detector operating at a detection wavelength of 234 nm. The method is specific and sensitive, with a quantification limit of approximately 60 ng/ml and a detection limit of 15 ng/ml at a signal-to-noise ratio of 3:1. The mean absolute recovery value was about 97%, while the within-day and between-day coefficient of variation and percent error values of the assay method were all less than 8%. The calibration curve was linear over a concentration range of 62.5-4000 ng/ml.

Matched MeSH terms: Biological Availability
Simple high-performance liquid chromatographic method for determination of ketoconazole in human plasma

Yuen KH, Peh KK

J Chromatogr B Biomed Sci Appl, 1998 Sep 18;715(2):436-40.
PMID: 9792531

A simple high-performance liquid chromatographic method using fluorescence detection was developed for the determination of ketoconazole in human plasma. The method entailed direct injection of the plasma sample after deproteinization using acetonitrile. The mobile phase comprised 0.05 M disodium hydrogen orthophosphate and acetonitrile (50:50, v/v) adjusted to pH 6. Analysis was run at a flow-rate of 1.5 ml/min with the detector operating at an excitation wavelength of 260 nm and an emission wavelength of 375 nm. The method is specific and sensitive with a quantification limit of approximately 60 ng/ml and a detection limit of 40 ng/ml at a signal-to-noise ratio of 3:1. Mean absolute recovery value was about 105%, while the within-day and between-day coefficient of variation and percent error values of the assay method were all less than 14%. The calibration curve was linear over a concentration range of 62.5-8000 ng/ml.

Matched MeSH terms: Biological Availability
Liquid chromatographic method for the determination of plasma itraconazole and its hydroxy metabolite in pharmacokinetic/bioavailability studies

Wong JW, Nisar UR, Yuen KH

J Chromatogr B Analyt Technol Biomed Life Sci, 2003 Dec 25;798(2):355-60.
PMID: 14643517

A sensitive and selective high-performance liquid chromatographic method was developed for the determination of itraconazole and its active metabolite, hydroxyitraconazole, in human plasma. Prior to analysis, both compounds together with the internal standard were extracted from alkalinized plasma samples using a 3:2 (v/v) mixture of 2,2,4-trimethylpentane and dichloromethane. The mobile phase comprised 0.02 M potassium dihydrogen phosphate-acetonitrile (1:1, v/v) adjusted to pH 3.0. Analysis was run at flow-rate of 0.9 ml/min with excitation and emission wavelengths set at 260 and 365 nm, respectively. Itraconazole was found to adsorb on glass or plastic tubes, but could be circumvented by prior treating the tubes using 10% dichlorodimethylsilane in toluene. Moreover, rinsing the injector port with acetonitrile helped to overcome any carry-over effect. This problem was not encountered with hydroxyitraconazole. The method was sensitive with limit of quantification of 3 ng/ml for itraconazole and 6 ng/ml for hydroxyitraconazole. The calibration curve was linear over a concentration range of 2.8-720 ng/ml for itraconazole and 5.6-720 ng/ml for the hydroxy metabolite. Mean recovery value of the extraction procedure for both compounds was about 85%, while the within-day and between-day coefficient of variation and percent error values of the assay method were all less than 15%. Hence, the method is suitable for use in pharmacokinetic and bioavailability studies of itraconazole.

Matched MeSH terms: Biological Availability
Fulltext The Effects of Minocycline on Spinal Root Avulsion Injury in Rat Model

Chin TY, Kiat SS, Faizul HG, Wu W, Abdullah JM

Malays J Med Sci, 2017 Mar;24(1):31-39.
PMID: 28381927 MyJurnal DOI: 10.21315/mjms2017.24.1.4

BACKGROUND: The neuroprotective role of minocycline in the treatment of brachial plexus injury is controversial.
OBJECTIVE: To study the neuroprotective effect of minocycline via different routes in adult Sprague Dawley rats with brachial plexus injury.
METHODS: The C7 nerve roots of the animals were avulsed via an anterior extravertebral approach. Traction force was used to transect the ventral motor nerve roots at the preganglionic level. Intraperitoneal and intrathecal minocycline (50 mg/kg for the first week and 25 mg/kg for the second week) were administered to promote motor healing. The spinal cord was harvested six weeks after the injury, and structural changes following the avulsion injury and pharmacological intervention were analysed.
RESULTS: Motor neuron death and microglial proliferation were observed after the administration of minocycline via two different routes (intraperitoneal and intrathecal) following traumatic avulsion injury of the ventral nerve root. The administration of intraperitoneal minocycline reduced the microglia count but increased the motor neuron count. Intrathecal minocycline also reduced the microglial count, with a greater reduction than in the intraperitoneal group, but it decreased the motor neuron count.
CONCLUSIONS: Intraperitoneal minocycline increased motor neuron survival by inhibiting microglial proliferation following traumatic avulsion injury of the nerve root. The inhibitory effect was augmented by the use of intrathecal minocycline, in which the targeted drug delivery method increased the bioavailability of the therapeutic agent. However, motor neuron survival was impaired at a higher concentration of minocycline via the intrathecal route due to the more efficient method of drug delivery. Microglial suppression via minocycline can have both beneficial and damaging effects, with a moderate dose being beneficial as regards motor neuron survival but a higher dose proving neurotoxic due to impairment of the glial response and Wallerian degeneration, which is a pre-requisite for regeneration.

Matched MeSH terms: Biological Availability
Bioequivalence of a generic metformin tablet preparation

Yuen KH, Wong JW, Billa N, Julianto T, Toh WT

Int J Clin Pharmacol Ther, 1999 Jul;37(7):319-22.
PMID: 10442505

The bioavailability of a generic preparation of metformin (Diabetmin from Hovid Sdn Bhd) was evaluated in comparison with a proprietary product (Glucophage from Lipha Pharma Ltd., UK).

Matched MeSH terms: Biological Availability
Comparative bioavailability study of two atenolol tablet preparations

Peh KK, Yuen KH, Wong JW, Toh WT

Drug Dev Ind Pharm, 1999 Mar;25(3):357-60.
PMID: 10071830

A study was conducted to compare the bioavailability of a generic product of atenolol (Normaten FC) with the innovator product, Tenormin. Twelve healthy adult volunteers participated in the study conducted according to a randomized, two-way crossover design. The preparations were compared using area under the plasma concentration-time curve AUC0-infinity, peak plasma concentration Cmax, and time to reach peak plasma concentration Tmax. No statistically significant difference was obtained between the Tmax values and the logarithmic transformed AUC0-infinity and Cmax values of the two products. Moreover, the 90% confidence interval for the ratio of the logarithmically transformed AUC0-infinity values of Normaten FC over those of Tenormin was found to lie between 0.82 and 0.98, while that of the logarithmically transformed Cmax values was between 0.82 and 1.09, both being within the bioequivalence limit of 0.80-1.25. The values of elimination half-life t1/2 between the two products were also found comparable and not significantly different statistically. The t1/2 values obtained in our study were slightly longer than those reported in the literature for other population groups.

Matched MeSH terms: Biological Availability
Comparative bioavailability study of a generic naltrexone tablet preparation

Yuen KH, Peh KK, Billa N

Drug Dev Ind Pharm, 1999 Mar;25(3):353-6.
PMID: 10071829

The bioavailability of a generic preparation of naltrexone (Narpan) was compared with the innovator product, Trexan. Twelve healthy volunteers participated in the study, conducted according to a completely randomized, two-way crossover design. The preparations were compared using the parameters area under the plasma concentration-time curve AUC0-infinity, peak plasma concentration Cmax, and time to reach peak plasma concentration Tmax. No statistically significant difference was observed between the logarithmic transformed AUC0-infinity and the logarithmically transformed Cmax values of the two preparations. Also, no statistically significant difference was observed between the untransformed Tmax values. In addition, the 90% confidence interval for the ratio of the logarithmic transformed AUC0-infinity values of Narpan over those of Trexan was found to lie between 0.87 and 1.01, while that of the logarithmic transformed Cmax values was between 0.94 and 1.23, both being within the bioequivalence limit of 0.80-1.25. The numerical values of the elimination half-life (t1/2) obtained with the two preparations were also not significantly different and were comparable to those reported in the literature.

Matched MeSH terms: Biological Availability

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