The new Chief Executive of Hydrodec has topped up his stake in the firm with £51,000-worth of shares, less than a month since he took up his new post. Ian Smale, whose appointment was announced in early November, bought 400,000 shares at 12.75p each. In January the company announced that its revenues for 2011 would be significantly ahead of the previous year. Sales of the branded Superfine oil rose 12% in the second half of 2011 versus the first six months of the year, giving some indication of the acceleration the company is currently seeing.There was also encouraging news from the US where Hydrodec received a draft approval from the US Environmental Protection Agency (EPA) to treat polychlorinated biphenyl (PCB) contaminated used oil. Just last week a non-executive director of the firm, Andrew Black, purchased £26,500-worth of shares. Meanwhile, a somewhat delayed announcement came from GlaxoSmithKline, which revealed that in early October of last year a person connected to director Patrick Vallance purchased 73 shares at 1,374.5p each. The transaction involved the re-investment of the dividend paid to shareholders on October 6th. At the end of January the firm announced that James Murdoch is to step down from the board of the pharmaceutical giant.Murdoch, who has recently been the focus of much controversy following the phone-hacking scandal surrounding News International's now-dissolved publication News of the World, joined the Glaxo board back in 2009 as a non-executive director. Top Director BuysInternational Oil and Gas Technology Ltd. (OGT) Director name: Mr Arthur CoppleAmount purchased: 15,999 @ $5.75 Value: $91,994HydroDec Group (HYR) Director name: Mr Ian SmaleAmount purchased: 400,000 @ 12.75p Value: £51,000Caledonia Mining Corp. (CMCL) Director name: Mr Stefan HaydenAmount purchased: 380,000 @ 5.59p Value: £21,242International Biotech Trust (IBT) Director name: Mr John AstonAmount purchased: 10,000 @ 177.70p Value: £17,770