HPMC- A Marvel Polymer for Pharmaceutical Industry-Patent review

: At the present time, designing of defined release dosage forms, either controlled, sustained, modified, are gaining much importance. For the development of such delivery systems, proper blend of polymers is required, so that drug release occurs by polymer erosion, swelling, diffusion/dissolution. HPMC (hydroxypropyl methyl cellulose) is the most commonly used cellulosic polymer available in various grades to develop such types of systems. Depending upon the molecular weight and viscosity chosen, it can be applied for emulsification, adhesion, bonding, thickening, suspension, film forming and gelation. It consists of polymeric units linked together, which retain water, thereby acting as an excellent hydrophilic gel-forming polymer. It generally hydrates on the outer surface to form a gelatinous layer. It swells, expands upon contact with water and releases the drug in a predetermined manner initially and then forms a viscous gel to control the release further. The objective of the present review is to overview the recent patents and articles of HPMC, its properties, grades and its use in various drug delivery systems and as a binder, dispersing agent, bioavailability enhancer and as capsule forming material have been identified and reviewed.

Localization of xyloglucan epitopes in the gelatinous layer of developing and mature gelatinous fibers of European aspen (Populus tremula L.) tension wood

There is controversy concerning the presence of xyloglucans in gelatinous (G) layers of Populus spp. tension wood, particularly in mature G-fibers. Transmission electron microscopy (TEM) immunogold localization combined with LM15 antibody (recognizes XXXG-motif of xyloglucans, heptasaccharide) was used to investigate the distribution of xyloglucan epitopes in both transverse and radial sections of P. tremula tension wood. Results provided clear evidence for the presence of xyloglucans in both mature and developing G-layers. Developmental decrease of LM15 epitope localization in G-layers was also detected during G-fiber maturation. High magnification TEM observations showed specific localization of LM15 epitopes on newly synthesized cellulose macrofibrils present in the innermost layer of developing G-layers adjacent to the cell lumen, suggesting linkage between xyloglucans and cellulose macrofibrils. Possible mechanisms were discussed for developmental changes of xyloglucan with respect to the different results reported in the literature.

New Trypetheliaceae from the Amazon basin in Rondônia (Brazil), the centre of diversity of the genus Astrothelium

The following 24 new species of Trypetheliaceae are described after three weeks of fieldwork in an area with a radius of 50 km around Porto Velho in Rondônia: Astrothelium bivelum with astrothelioid ascomata, 5-septate ascospores with polar gelatinous caps, and a thallus without lichexanthone; A. curvisporum with bent, 5-septate ascospores of 115–135×29–36 μm with a 17–22 μm thick gelatinous layer; A. decemseptatum with pseudostroma that are essentially black and look like breaking through the bark, with anthraquinones mostly on the pseudostromata but also on some parts of the thallus, best seen under UV light as the colour of the pruina is not very strong, and ascospores (7–)9–11-septate, fusiform, 50–65×11–17 μm; A. disjunctum with black pseudostroma and ascospores 3-septate, (27–)29–33×(8–)12–14 μm; A. duplicatum which is similar to A. mesoduplex, but pseudostroma are only yellowish inside and ascospores 45–55×11–15 μm; A. eumultiseptatum which is similar to A. eustomum, but with 9–11-septate ascospores of 65–70×15–17 μm; A. eustomurale which is also similar to A. eustomum, but with submuriform ascospores of 37–45×15–19 μm; A. flavoduplex which is similar to A. mesoduplex, but with ascospores 110–350×20–27 μm and the thallus containing lichexanthone; A. flavomurisporum with deeply immersed ascomata with muriform ascospores of 165–200×28–35 μm, with a distinctly thickened central septum and yellow oil; A. flavostromatum which is close to A. aeneoides and mainly differs by the bullate thallus and the cream pseudostromata; A. flavum which is similar to A. aeneum, but differs in the contrast between the linear to reticulate yellow stromata and the unpigmented thallus, and the ascospores of 16–18×6–7 μm; A. mesoduplex which is similar to A. flavoduplex, but with ascospores 90–100×20–23 μm and a thallus without lichexanthone; A. nigrum with mostly conical black pseudostromata that contrast sharply with the thallus, superficially resembling Pyrenula infraleucotrypa; A. novemseptatum which is similar to A. eumultiseptatum, but without lichexanthone anywhere in the thallus or pseudostroma; A. ochroleucoides which is similar to A. corallinum, but with lichexanthone on the thallus and pseudostromata; A. octoseptatum which is similar to A. eumultiseptatum, but with the whole pseudostroma, not just the ostioles, containing lichexanthone, and ascospores somewhat asymmetrical, which is highlighted by the unusual dominant even number of septa (eight) and the asymmetrically placed central septum in the case of uneven septum numbers; A. quatuorseptatum which is similar to A. octoseptatum Aptroot & M. Cáceres, but without lichexanthone, ascospores somewhat asymmetrical, which is highlighted by the unusual dominant even number of septa (four) and the asymmetrically placed central septum in the case of uneven septum numbers; A. robustosporum with solitary ascomata with an eccentric ostiole, and ascospores 11–15-septate, 90–125×20–27 μm; A. solitarium which is similar to A. ceratinum (Fée) Aptroot & Lücking, but with ascospores 33–36×10–11 μm; A. stromatofluorescens which is close to A. phlyctaena, but with lichexanthone only on the pseudostroma, not on the thallus; A. supraclandestinum is close to A. subclandestinum, but the hamathecium is not inspersed; A. testudineum with solitary ascomata with an eccentric ostiole, an inspersed hamathecium, and ascospores 8 per ascus, muriform, 50–65×23–27 μm; A. xanthosuperbum which is similar to A. disjunctum, but with muriform ascospores, 130–160×28–35 μm; and Pseudopyrenula flavoreagens which is similar to P. subgregaria, but with lichexanthone in the thallus. Only a few species were also found elsewhere, such as other areas of Brazil, or in Venezuela, Colombia, Guyana, Panama, Australia and/or Papua New Guinea. Currently, 55 species of Trypetheliaceae are known from this spot, including 46 species of Astrothelium. The Amazon basin is the centre of diversity for the family, at least for Astrothelium, the largest genus in the family.

New species and interesting records of Arthoniales from the Amazon, Rondônia, Brazil

The following new species of Arthoniales are described from Rondônia: Alyxoria fuscospora with 3-septate clavate ascospores of 20–23×4·5–5·5 µm having a gelatinous layer soon appearing evenly brown (also known from other tropical countries). Chiodecton complexum with discrete soralia, immersed apothecia in branched lines and 3-septate ascospores (26–)33–40×2·5–3·5 µm. Coniarthonia rosea, similar to C. pulcherrima but with the apothecia pink and more irregular in outline and the ascospores 13–16×5·5–6·5 µm. Cresponea flavosorediata with yellow-olive soralia, apothecia with yellow pruina and 7–9-septate ascospores, 26–38(–50)×5·0–6·5 µm. Cresponea lichenicola, lichenicolous on a Pyrenula, with 0·1–0·3 mm wide apothecia with yellow pruina. Eremothecella helicella with helicoid curved c. 17–29-septate conidia c. 70–95×2 µm long if uncoiled, with septa 3–6 µm apart. The Arthoniales are a speciose component of the lowland rainforest of Rondônia. A key is provided to the corticolous species of most groups of Arthoniales found in Rondônia. The foliicolous species found so far are listed. Most are new records for Rondônia. Chrysothrix occidentalis is new to the Neotropics.

Pyrenocarpous lichens (except Trypetheliaceae) in Rondônia

The following new species of pyrenocarpous lichens are described from Rondônia: Agonimia tenuiloba: corticolous, thallus with minute flabellate lobes developing goniocysts; ascomata smooth, grey, ellipsoidal; ascospores densely muriform, 30–50(–76)×20–35 µm. Anisomeridium lateriticum: saxicolous; conidiomata sessile, pyriform, ostiole with brown and hyaline septate setae; conidia simple to 1-septate, 8–11×2·0–2·5 µm. Anisomeridium triseptatum: corticolous, ascomata with lateral ostioles; ascospores (1–)3-septate, 25–30×7·5–10·0 µm, often with gelatinous appendages. Mycomicrothelia megaspora: ascospores ornamented, 1-septate, (27–)29–35(–40)×8–12 µm, often with a gelatinous layer 6–15 µm thick. Porina linearispora: corticolous; thallus green, shiny; ascomata immersed, 0·2–0·3 mm; ascospores filiform, (7–)9(–13)-septate, 75–90×1·5–2·0 µm. Porina maxispora: corticolous; thallus green, matt; ascomata immersed, 0·5–0·7 mm; ascospores filiform, (17–)23–35-septate, 95–110×4·5–5·5 µm. Porina novemseptatoides: saxicolous; thallus very thin, brown, glossy; ascomata superficial, 0·1–0·2 mm; ascospores fusiform, (7–)9-septate, 21–24×4·5–5·0 µm, with a c. 5 µm thick gelatinous layer. Porina termitophila: terricolous; thallus greyish green; ascomata emergent, 0·15–0·20 mm; ascospores fusiform, 1–3-septate, 13–15×2·5–3·0 µm. Pyrenula bispora: corticolous, thallus whitish, ascomata dispersed; hamathecium inspersed; ascospores 2 per ascus, muriform, 55–75×19–23 µm. Pyrenula leptaleoides: corticolous; thallus green to pale brown; ascomata deeply immersed in bark, with long necks fused in joint ostioles visible as brown dots on the surface; ascospores 23–27×8–11 µm, with rather angular lumina. Pyrenula rhomboidea: corticolous; thallus olive-brown; ascomata single, immersed; ascospores irregularly uniseriate, clavate-rhomboidal, 11–13×3·5–4·0 µm.A key is provided to all species of pyrenocarpous lichens (except Trypetheliaceae) found in Rondônia. Nearly all species are new reports for Rondônia. Aspidothelium glabrum, Pyrenula leucotrypa and P. micheneri are newly reported for South America. The usually foliicolous Strigula nitidula is reported for the first time from bark.The high lichen diversity is explained by the poor soils, supporting an only moderately dense forest where enough light can reach the tree trunks at ground level to support a rich flora of crustose lichens usually confined to the upper trunks.

CHARACTERISTICS OF TROCHODENDRON ARALIOIDES TENSION WOOD FORMED AT DIFFERENT INCLINATION ANGLES

To assess the characteristics of tension wood (TW) in Trochodendron aralioides Sieb. et Zucc., seedling stems were artificially inclined at angles of 30° (TW- 30), 50° (TW-50), and 70° (TW-70) from the vertical. At all angles, the growth promotion was pronounced on the upper side of the inclined stems, where excessive tensile growth stress was observed. A gelatinous layer (G-layer) formed in the tracheids of TW. The cell wall structure of the tracheids in TW was S1 + G. The G-layer had a small pit aperture angle <10°. TW-50 showed larger tensile growth stress, a thicker G-layer area, and a smaller pit aperture angle of the Glayer than TW-30 and TW-70. Lower levels of Klason lignin and hemicellulose and higher levels of α-cellulose content were observed in TW-50. In addition, an increase in glucose content and a decrease in xylose content in holocellulose were observed in TW-50. Therefore, it can be concluded that the degree of TW varied with different inclination angles.

Structural analysis of the Pimelodus maculatus (Lacépède, 1803) embryogenesis (Siluriformes: Pimelodidae)

The fish embryonic development comprises the events between the egg fertilization up to larvae hatching, being useful for the identification of viable eggs in productivity and survival studies as well as in raising experiments of several species. The goal of the present study was to characterize the embryonic development of Pimelodus maculatus (Siluriformes; Pimelodidae). The embryogenesis was typical of teleosteans, but with differences in relation to other species such as duration of development, type of blastocoel, moment of somite segmentation among others. Six stages of embryonic development were defined: zygote, cleavage, blastula, gastrula, organogenesis (divided in phases: early segmentation and late segmentation) and hatching with a period of incubation equal to 13 hours at 29 ºC and 17 hours at 25 ºC. The extruded oocytes presented a mean diameter of 812 µm before and 1066 µm after hydration. When fertilized, they presented a yellowish coloration and a gelatinous layer surrounding the chorion. The cleavage pattern is described as: 2; 4; 8 (4x2); 16 (4x4); 32 (4x8) and 64 (2x4x8) blastomeres up to morula phase (+64 cells). It was also possible to observe at this phase, the beginning of the formation of the yolk syncyctial layer (YSL). Afterwards, the blastula and gastrula stages followed. The end of gastrula was characterized by the formation of the yolk plug. Subsequently, the differentiation between cephalic and caudal regions began, along with the embryo elongation, structuring of optic, Kupffer's and otic vesicles besides a previously unidentified structure in the yolk syncyctial layer. The end of this stage is typified by the tail detachment. The late segmentation phase was distinguished by a free tail, presence of more than 30 somites, optic and otic vesicles, development of posterior intestine, pigmentation of cephalic and caudal regions of yolk sac and embryo growth. The recently-hatched larvae presented a primordial digestive tract, quite evident and pigmented eyes, closed mouth, encephalic vesicles and a mean length of 3410 µm.