Khat (Catha edulis) is an evergreen tree/shrub that is thought to affect sexual motivation or libido. Its positive effect on sexual desire is more frequently observed in females than in males and occurs when khat is chewed. Thus, khat's effects on sexual behavior may depend on the release mode of its active constituent.
Compaction of controlled-release coated pellets into tablets is challenging because of the fusion of pellets and the rupturing of coated film. The difficulty in compaction intensifies with the use of extremely water-soluble drugs. Therefore, the present study was conducted to prepare and compact pellets containing pseudoephedrine hydrochloride as an extremely water-soluble model drug. The pellets were produced using an extrusion-spheronization technique. The drug-loaded pellets were coated to extend the drug release up to 12-h employing various polymers, and then they were compressed into tablets using microcrystalline cellulose Ceolus KG-801 as a novel tabletting excipient. The in vitro drug release studies of coated pellets and tablets were undertaken using the USP basket method in dissolution test apparatus I. The amount of drug released was analyzed at a wavelength of 215 nm. The combined coatings of hydroxypropyl methylcellulose and Kollicoat SR-30D yielded 12-h extended-release pellets with drug release independent of pH of dissolution medium following zero-order kinetics. The drug release from the tablets prepared using inert Celous KG-801 granules as tabletting excipient was found faster than that of coated pellets. However, a modification in drug release rate occurred with the incorporation of inert Ceolus KG-801 pellets. The drug dissolution profile from tablets containing 40% w/w each of coated pellets and inert granules along with 20% w/w inert pellets was found to be closely similar to that of coated pellets. Furthermore, the friability, tensile strength, and disintegration time of the tablets were within the USP specifications.
Curcumin, the main active constituent of turmeric herb (Curcuma longa L.) have been reported to possess many medicinal values. The application of curcumin in dermatological preparations is limited by their intense yellow color property, which stains the fabric and skin. The objectives of this study were to reduce the color staining effect and enhance the stability of curcumin via microencapsulation using gelatin simple coacervation method. As for curcumin, ethanol and acetone were used as coacervating solvents. Curcumin was dispersed in ethanol while dissolved in acetone. Irrespective of the types of coacervating solvents used, microencapsulation resolved the color-staining problem and enhanced the flow properties and photo-stability of curcumin. Nevertheless, it was found that more spherical curcumin microcapsules with higher yield, higher curcumin loading, and higher entrapment efficiency were obtained with acetone than ethanol. The in vitro release of curcumin after microencapsulation was slightly prolonged. Further evaluation of the effects of solubility of core materials in coacervating solvent or polymeric aqueous solution using six different drug compounds, namely, ketoconazole, ketoprofen, magnesium stearate, pseudoephedrine HCl, diclofenac sodium, and paracetamol, suggested that the solubility of core materials in aqueous polymeric solution determined the successful formation of microcapsules. Microcapsules could only be formed if the core materials were not dissolved in the aqueous polymeric solution while the core materials could either be dissolved or dispersed in the coacervating solvent. In summary, microencapsulation not only circumvents the color-staining problem but also improved the stability and flowability of curcumin. The solubility of core material in aqueous polymeric solution plays a pivotal role in determining the successful formation of microcapsules.
The potential of using poly-(ethylene oxide)-block-distearoyl phosphatidyl-ethanolamine (mPEG-DSPE) polymer to prepare BDP-loaded micelles with high entrapment efficiency and mass median aerodynamic diameter of less than 5 microm demonstrating sustained release properties was evaluated. The result showed that lyophilized BDP-loaded polymeric micelles with entrapment efficiency of more than 96% could be achieved. Entrapment efficiency was affected by both the drug to polymer molar ratio and the amount of drug used. Investigation using FTIR and DSC confirmed that there was no chemical or physical interaction and the drug was molecularly dispersed within the micelles. TEM images showed that the drug-loaded polymeric micelles were spherical in shape with multivesicular morphology. Further analysis by photon correlation spectroscopy indicated that the particle size of the BDP-loaded micelles was about 22 nm in size. In vitro drug release showed a promising sustained release profile over six days following the Higuchi model. The mass median aerodynamic diameter and fine particle fraction were suitable for pulmonary delivery. Moreover, the small amount of deposited drug in the induction port (throat deposition) suggested possible reduction in incidence of oropharyngeal candidiasis, a side effect normally associated with inhaled corticosteroids therapy. The high encapsulation efficiency, comparable inhalation properties, sustained release behavior together with biocompatibility nature of the polymer support the potential of BDP-loaded polymeric micelles as a versatile delivery system to be used in the treatment of asthma and chronic obstructive pulmonary disease.
To investigate the interpolymer complexation between Carbopol 934P (CP) and various grades of polyvinylpyrrolidone (PVP) (K90, K32, C15, and VA/S-630).
A simple and selective high-performance liquid chromatography (HPLC) method using ultraviolet detection was developed for simultaneous determination of fusidic acid and betamethasone dipropionate in a cream formulation. A Supelcosil LC18 column was used for chromatographic separation. The mobile phase consisted of acetonitrile and 0.01 M disodium hydrogen orthophosphate (70:30, % v/v) adjusted to pH 6 with glacial acetic acid. Analysis was run at a flow rate of 1.0 mL/minute with the detector operating at 235 nm. The standard calibration curve was linear over a concentration range of 0.3 to 1.2 mg/mL for fusidic acid and 9.6 to 38.4 micrograms/mL for betamethasone dipropionate. The average recovery values for fusidic acid and betamethasone dipropionate were almost 100%. The within-run and between-run coefficient of variation and percent error values for the two drugs were all less than 2% and +/- 3%, respectively.
This study examined the mechanical (hardness, compressibility, adhesiveness, and cohesiveness) and rheological (zero-rate viscosity and thixotropy) properties of polyethylene glycol (PEG) gels that contain different ratios of Carbopol 934P (CP) and polyvinylpyrrolidone K90 (PVP). Mechanical properties were examined using a texture analyzer (TA-XT2), and rheological properties were examined using a rheometer (Rheomat 115A). In addition, lidocaine release from gels was evaluated using a release apparatus simulating the buccal condition. The results indicated that an increase in CP concentration significantly increased gel compressibility, hardness, and adhesiveness, factors that affect ease of gel removal from container, ease of gel application onto mucosal membrane, and gel bioadhesion. However, CP concentration was negatively correlated with gel cohesiveness, a factor representing structural reformation. In contrast, PVP concentration was negatively correlated with gel hardness and compressibility, but positively correlated with gel cohesiveness. All PEG gels exhibited pseudoplastic flow with thixotropy, indicating a general loss of consistency with increased shearing stress. Drug release T50% was affected by the flow rate of the simulated saliva solution. A reduction in the flow rate caused a slower drug release and hence a higher T50% value. In addition, drug release was significantly reduced as the concentrations of CP and PVP increased because of the increase in zero-rate viscosity of the gels. Response surfaces and contour plots of the dependent variables further substantiated that various combinations of CP and PVP in the PEG gels offered a wide range of mechanical, rheological, and drug-release characteristics. A combination of CP and PVP with complementary physical properties resulted in a prolonged buccal drug delivery.
Modified-release drug spheroids coated with an aqueous mixture of high-viscosity hydroxypropylmethylcellulose (HPMC) and sodium carboxymethylcellulose (NaCMC) were formulated. The preparation of core drug spheroids and the coating procedures were performed using the rotary processor and a bottom-spray fluidized bed, respectively. Dissolution studies indicated that incorporation of suitable additives, such as poly(vinylpyrrolidone) (PVP) and poly(ethylene glycol) 400 (PEG) improved the flexibility and integrity of the coat layer by retarding the drug release. An increase in coating levels applied generally retarded the release rate of the drug. However, the ratio of HPMC to NaCMC in the mixed, plasticized polymeric coat played a more dominant role in determining the dissolution T50% values. The optimal ratio of HPMC to NaCMC for prolonged drug release was found to be 3:1, whereas an increase in the amount of NaCMC in the mixed polymer coat only increased drug release. The synergistic viscosity effect of HPMC and NaCMC in retarding drug release rate was greater in distilled water than in dissolution media of pH 1 and 7.2. Cross-sectional view of the scanning electron micrograph showed that all of the coated spheroids exhibited a well-fused, continuous, and distinct layer of coating film. The drug release kinetics followed a biexponential first-order kinetic model.
To determine the incidence of insulin dependent diabetes mellitus (IDDM) in children 0-12 years of age in Singapore, which has a population of 2.9 million.
Diabetes mellitus is a common chronic disease in Singapore. Its occurrence in pregnant women was 1.3% in a previous report. In a survey of 145 consecutive pregnant women registered at Alexandra Hospital the incidence of gestational diabetes was 13.1% when a total screen with 75 gm oral glucose challenge was used. The mean age of this sample was 27 years and the mean gestation at screening 33 weeks. There was an excess of Malay and Indian patients. Fifty percent had traditional risk factors tor gestational diabetes. Whether this higher incidence is a result of more stringent screening and/or increased occurrence remains to be confirmed.
Singapore is a tropical island city-state with a population of 2.4178 million consisting of Chinese (76.7%), Malays (14.7%), Indians (6.4%) and other races (2.2%). A diabetic survey of the adult population, aged 15 years and above, carried out in 1975, shows that the prevalence of diabetes is 1.99%; it is higher in males (2.36%) than in females (1.64%). It occurs mainly in the age group 40 years and above (5.08%) and is uncommon in the age group 15-39 years (0.40%). In males, the highest prevalence of diabetes (7.0%) is in the age group 45-49 years while in females the highest prevalence (7.2%) is in the age group 55-59 years. 43.3% of the diabetics are of normal weight while 44.3% are overweight and 12.4% are underweight. 59.6% of the diabetics are newly diagnosed while 40.4% are known diabetics; 64.3% of the newly diagnosed diabetics have no symptoms. The prevalence of diabetes among the Indians (6.07%) is significantly higher than that in Malays (2.43%) and Chinese (1.55%). Indian diabetics have a slightly higher positive family history of diabetes (12.7%) than Malays (10.9%) and Chinese (6.5%). Obesity is commoner in Malay diabetics (64.7%) than in Chinese (41.6%) and Indians (35.7%). The possible factors leading to the significantly higher prevalence of diabetes among the Indians compared to the other ethnic groups in Singapore are discussed. It is suggested that the Indian gene is susceptible to diabetes (diabetic genotype) and increased food consumption, altered lifestyle and greater obesity leads to the expression of diabetes.(ABSTRACT TRUNCATED AT 250 WORDS)
A country-wide diabetic survey of the population (age 15 years and above) of Singapore shows that the prevalence of diabetes mellitus in Singapore is 1.99 percent. It is commoner in males (2.36 percent) than in females (1.64 percent). The prevalence of diabetes in the age group 15-39 years is only 0.40 percent and in the age group 40 years and older it is 5.08 percent. The prevalence of diabetes in Indians (6.07 percent) is significantly higher than that in Malays (2.43 percent) and Chinese (1.55 percent). Indian diabetics have an insignifi"cantly higher incidence of positive family of diabetes (12.7 percent) than Malays (10.9 percent) and Chinese (6.5 percent). Obesity was commoner in Malay diabetics (67.4 percent) than in Chinese diabetics (41.6 percent) and Indian diabetics (35.7 percent). The survey shows that 40.4 percent of the diabetics are known while 59.6 percent of the diabetics are newly diagnosed. The majority of the diabetics are treated with oral hypoglycaemic drugs (71.5 percent) and only 4.8 percent are receiving insulin injections. A mong the female diabetics, 63.0 percent have 4 or more pregnancies and large babies at birth are recorded in 12.3 percent. In the newly diagnosed diabetics, 64.3 percent have no symptoms. The complications of the diabetics are hypertension (26.8 percent), nephropathy (9.8 percent), retinopathy (8.5 percent), coronary heart disease (6.1 percent), skin infection (4.6 percent) and neuropathy (3.3 percent). The high prevalence of diabetes among the Indians is likely to be due to a genetic predisposition coupled with an environmental factor (obesity), although this hypothesis is not conclusively demonstrated by the present study.