Influence of Drying Methods and Vacuum Impregnation on Selected Quality Factors of Dried Sweet Potato

A comparative study was conducted on the effect of vacuum impregnation and drying methods on the production of dried sweet potatoes with high bioactivity. The present study determined the quality and physicochemical properties of dried sweet potato depending on the used impregnating solutions. Sweet potatoes were pretreated in freshly squeezed onion (O) and kale (K) juice, onion and kale (OK) mixture (1:1), and sodium chloride solution. Vacuum impregnation (VI) was carried out under reduced pressure (6 kPa) for 2 min, after which the impregnating solution was dispensed and maintained under vacuum for 4 min. Sweet potato slices were dried using vacuum drying (VD) and freeze drying (FD) methods. Higher content of polyphenols, carotenoids, and chlorophyll, as well as increased antioxidant capacity and higher VOC profile, were recorded for the dried products obtained using the sublimation method. The use of vacuum impregnation reduced the hardness of the products and other textural characteristics, such as cohesiveness, springiness, and gumminess. Furthermore, we found that vacuum impregnation pretreatment was a beneficial method for improving the characteristics of dried vegetables. The highest content of phenolics, carotenoids, and chlorophylls in dried sweet potatoes were recorded when samples were impregnated with onion and kale juice. For the fresh sweet potato, the highest contribution in VOC composition had phenylacetaldehyde (44.90%), (E)-2-octen-1-al (9.43%), and benzaldehyde (8.18%), respectively. The interesting content of VOC profile compounds in dried sweet potatoes was recorded when samples were impregnated with kale juice.

Heat Transfer Measurements for Array Jet Impingement with Castellated Wall

Impingement cooling is one of the powerful cooling methods in high-temperature devices. For gas turbine applications, impingement cooling is commonly applied in the transition piece of a combustor and in the leading edge, suction, and pressure sides of a turbine blade/vane. In the suction side and pressure side, impingement cooling is applied as a form of an array jet. However, due to the small gap between the jet hole and target surface, the wall jet faces a crossflow inside of the gap. This crossflow has an adverse effect on jets and deteriorates the heat transfer performance. Therefore, several studies have been conducted to minimize the crossflow effect. The present study also investigated the effect of crossflow reduction in the gap by having a castellated hole plate. The heat transfer was measured using the naphthalene sublimation method. Heat transfer data are compared among three different cases. One is the baseline case which is simple array jets. Others are the castellated cases with and without rib structures on the target wall. Jet-to-jet spacing(s/d) and jet-to-target spacing(z/d) are selected as geometrical variables. Also, the experiments were conducted for the Reynolds numbers (based on jet hole diameter) of 5,000, 15,000 and 30,000. The baseline case was named as B case, the castellated case without rib as C case and with rib as CR case. Both castellated cases showed the crossflow reduction effect and resulted high and similar Nusselt number values.

Development of gastroretentiv floating tablets of losartan potassium by sublimation method

The purpose of present study was to formulate and Evaluate Sustained release floating tablet of losartan Potassium using Camphor and Polyethylene Oxide as Pore formation for floating and release retarding agent respectively to improve gastric residence time and patient compliance in management of hypertension. The tablet was prepared by direct compression by using HPMC K4 as dry binder. Camphor and PEO as floating and release retarding agent for sustained release floating tablet. Post compression was done to increase the hardness and floating time of tablet. Release modifier was used to speed up the release of drug from sustained release floating tablet. The effect of two independent variables like amount of Sublimating agent (camphor) and amount of Polyethylene oxide (PEO) on Q30min, Q360min, and Q720min was optimized using 32 factorial design and analyzed using the software design expert 10.0.3. The observed (actual values) responses were coincided well with the predicted values, given by the optimization technique. The floating tablet were characterized by FTIR for drug excipient compatibility.

Assessment of Chokeberry Powders Quality Obtained Using an Innovative Fluidized-Bed Jet Milling and Drying Method with Pre-Drying Compared with Convection Drying

There is a need and great interest among food producers in obtaining powders from fruit and vegetables of both high nutritional value and sensory qualities superior to those hitherto obtained by convection drying (CD) and spray drying methods and cheaper to prepare than the sublimation method. This study is focused on whether powders can be obtained from fruit berries with a sticky structure, using the chokeberry (Aronia melanocarpa) as a test example, by a combined fluidized-bed jet milling and drying (FBJD) of pre-dried fruit by CD to an adequate water activity (aw). The pre-drying step reduced sticking between fruit particles during the simultaneous drying and grinding processes of the FBJD method in order to obtain powders of desired granulation. Three different pre-drying temperatures of 50, 60, and 70 °C were tested for levels of microorganisms in chokeberries at a water activity of 0.4. Vitamin C content and antioxidant properties were also examined along with polyphenol separation. Fruit pre-dried at 60–70 °C had significantly higher vitamin C and polyphenolic content and greater antioxidant properties than those pre-dried at 50 °C. Further studies were thus undertaken on powders pre-dried at 70 °C in which antioxidant properties, vitamin C, and polyphenols content were also compared with CD obtained powders. The FBJD method combined with CD pre-drying proved superior to just using the CD method, where powders had a greater preservation of vitamin C at 84% (CD powders 35%), a 12% higher total polyphenol content, and a 10% higher antioxidant activity. The test method also uses a much shorter drying time than the CD method, because the grinding of the hard-textured material takes only few minutes.

Development of Nifedipine sublingual tablets using disintegrants as release modifiers

The current study mainly focused on treating cardiovascular diseases such as angina pectoris and chronic hypertension by modifying the existing commercial tablet available for Nifedipine. The limitation of Nifedipine is poor solubility, which comes under BCS class II drug category, which needs improvement in formulation to achieve better bioavailability. The objective of this research work is to enhance the oral bioavailability (first-pass metabolism in the liver (42–56%)) of Nifedipine by improving dissolution property. Sublingual fast dissolving tablets of Nifedipine formulated by sublimation method, designed to increase its disintegration time in the presence of saliva. This formulation is helpful for paediatric and geriatric patients who are unable to swallow the conventional tablet. Sublimation of camphor makes the tablet more porous and improve disintegration time as well. The direct compression method is used with different ratio of Croscarmellose Sodium (CS) and Sodium Starch Glycolate (SSG) as super disintegrants to formulate Nifedipine loaded Sublingual tablets. All formulations contain various ratio between super disintegrants and camphor, followed by the sublimation method. FTIR and DSC studies were conducted to investigate compatibility between drugs and disintegrants. Formulated tablets were subjected for precompression parameters, e.g., bulk density, tapped density, Carr’s index, Hausner’s ratio, angle of repose and for post-compression parameters, e.g. weight variation, thickness, hardness, friability, drug content, wetting time, disintegration time followed by dissolution study and found satisfactory as per IP.

A Comparative Evaluation of Fast Dissolving Tablets of Acetaminophen Using Super-disintegrant Blends and Sublimation Method

Fast disintegrating tablets (FDTs) are gaining prominence as drug delivery systems and emerging as one of the popular and widely accepted dosage forms, especially for the peadiatric and geriatric patients. This study aims to evaluate and compare the tablet properties of fast disintegrating tablets of acetaminophen prepared by super-disintegrant blends and sublimation methods. Two groups of tablets comprising various batches were prepared by wet granulation. Granules batches of one group of tablets (A-G) were prepared with different concentrations of sodium starch glycolate and croscarmellose sodium while the other group of tablets (H-N) were incorporated with varying concentrations of menthol into the batches. The granules were subjected to analysis and compressed into tablets. The post-compression parameters of the tablets such as weight uniformity, crushing strength, friability, wetting and disintegration times, as well as dissolution studies were evaluated. Drug-excipient compatibility studies using Fourier transform infrared (FTIR) analysis was also carried out. Granules were fair to good in flow with Carr’s indices ≤ 20.14 and angles of repose ranging from 21.34 to 35.00°. Tablets crushing strength values were between 3.44 to 8.26 kp while their friability values were < 1.52%. They showed wetting and disintegration times that were ≥ 0.18 and ≥ 0.25 min. Dissolution studies showed that four batches of tablets (two from each method used in formulation) achieved 100% drug release within 30 min. FTIR analysis shows no interactions between acetaminophen and excipients used in formulation. Tablets from both methods were comparable in their tablet properties but the disintegrant blend tablets exhibited superior crushing strengths, hence formed harder tablets, while the sublimation method tablets were superior in their wetting and disintegration times. Keywords: acetaminophen, super-disintegrants, sublimation, tablet parameters